Synthesis and diastereoselective complexation of enantiopure sulfinyl dienes: The preparation of sulfinyl iron(0) dienes

Article abstract of DOI:10.1021/jo970693a

The preparation of a diverse array of enantiomerically pure 1- and 2- sulfinyl dienes has been achieved via Stille coupling of halovinyl sulfoxides and vinyl stannanes, hydrogenation of 1-sulfinyl-1-en-3-ynes, or vinylcupration of 1-sulfinyl alkynes. Form

Full text of DOI:10.1021/jo970693a

6326
J . Org. Chem. 1997, 62, 6326-6343
Syn th esis a n d Dia ster eoselective Com p lexa tion of En a n tiop u r e
Su lfin yl Dien es: Th e P r ep a r a tion of Su lfin yl Ir on (0) Dien es
Robert S. Paley,* Alfonso de Dios, Lara A. Estroff, J ennifer A. Lafontaine, Carlos Montero,
David J . McCulley, M. Bele´n Rubio, Maria Paz Ventura, and Heather L. Weers
Department of Chemistry, Swarthmore College, Swarthmore, Pennsylvania 19081
Roberto Ferna´ndez de la Pradilla,* Sonia Castro, Roc´ıo Dorado, and Miguel Morente
Instituto de Quı´mica Orga´nica, CSIC, J uan de la Cierva 3, 28006 Madrid, Spain
Received April 17, 1997X
The preparation of a diverse array of enantiomerically pure 1- and 2-sulfinyl dienes has been
achieved via Stille coupling of halovinyl sulfoxides and vinyl stannanes, hydrogenation of 1-sulfinyl-
1-en-3-ynes, or vinylcupration of 1-sulfinyl alkynes. Formation of the corresponding sulfinyl diene
iron(0) tricarbonyl complexes was accomplished by utilizing Fe(CO)5/NMO or (bda)Fe(CO)3 as iron(0)
tricarbonyl transfer reagents. Installation of the iron(0) tricarbonyl fragment was shown to be
highly diastereoselective (10-16:1) for (R)-(1Z)-1-sulfinyl dienes, most likely as a result of allylic
1,3-strain. The synthesis of a 1-sulfinyl-1,3,8,10-tetraene is also described.
In tr od u ction
program which seeks to explore the feasibility and di-
astereoselectivity of organotransition metal chemistry
which is centered about the use of the chiral sulfoxide
functionality as the chiral control element.
The use of enantiomerically pure sulfoxides to direct
the absolute stereochemistry of emerging chiral centers
has been the primary feature of numerous publications
over the last 20 years.1 Among the best known examples
of this chemistry are conjugate additions to R-sulfinyl
enones,2 diastereoselective Diels-Alder reactions,3 ad-
ditive Pummerer reactions,4 and reductions of â-keto
sulfoxides.5 However, despite recent advances in orga-
notransition metal chemistry directed toward organic
synthesis,6 there have been only isolated reports7 which
have described procedures which would extend the use
of the sulfoxide group beyond traditional main-group
transformations. We have therefore initiated a research
Among the scattered reports of transition metal com-
plexes used in conjunction with sulfoxides, few have been
within the context of asymmetric synthesis. For ex-
ample, Hiroi7a demonstrated that 3-alkyl-1-sulfinylcyclo-
pent-1-enes could be prepared with good diastereoselec-
tivity by taking advantage of a Pd(0)-catalyzed 1-sulfinyl-
1-vinylcyclopropane rearrangement. However, the origin
of the stereoselectivity observed in this process was not
as a result of the influence of the sulfoxide on the
presumed intermediate sulfinyl-π-allyl-Pd(0) complex,
but rather was due to a prior non-transition metal
mediated diastereoselective vinyl sulfoxide cyclopropa-
nation. Moreto´7b reported a Ni(CO)4-mediated approach
to homochiral fused and spiro cyclopentenones using
alkynyl sulfoxides and allylic bromides, but the diaste-
reoselectivity of this process was only moderate. More
recently, Hua7c has prepared a series of sulfinylferrocenes
for possible use in asymmetric catalysis. Other instances
of transition metal complexes bearing sulfinyl groups
have included the syntheses of η4-(3-sulfinyl enone)-
Fe(CO)3 complexes7d and of η6-sulfinyl arene-Cr(CO)3
complexes,7e,f but these have employed racemic sulfoxides.
Taken together, these examples reveal that the area of
asymmetric synthesis employing enantiopure sulfoxides
in conjunction with transition metal chemistry is still
largely unexplored and unrealized.
X Abstract published in Advance ACS Abstracts, August 1, 1997.
(1) For reviews, see: (a) The Chemistry of Sulphones and Sulphox-
ides; Patai, S., Rappoport, Z., Stirling, C. J . M., Eds.; J ohn Wiley &
Sons: New York, 1988. (b) Solladie´, G. Synthesis 1981, 185-196. (c)
Walker, A. J . Tetrahedron: Asymmetry 1992, 3, 961-968. (d) Carren˜o,
M. C. Chem. Rev. 1995, 95, 1717-1760. (e) Aversa, M. C.; Barattucci,
A.; Bonaccorsi, P., Giannetto, P. Tetrahedron: Asymmetry 1997, 8,
1339-1367.
(2) Posner, G. H. Acc. Chem. Res. 1987, 20, 72-87.
(3) (a) Ronan, B.; Kagan, H. B. Tetrahedron: Asymmetry 1992, 3,
115-122. (b) Arai, Y.; Matusi, M.; Koizumi, T.; Shiro, M. J . Org. Chem.
1991, 56, 1983-1985. (c) Carren˜o, M. C.; Garc´ıa-Ruano, J . L.; Urbano,
A. Tetrahedron Lett. 1989, 30, 4003-4006.
(4) (a) Marino, J . P.; Laborde, E.; Paley, R. S. J . Am. Chem. Soc.
1988, 110, 966-968. (b) Marino, J . P.; Perez, A. D. J . Am. Chem. Soc.
1984, 106, 7643-7644. (c) Marino, J . P.; Ferna´ndez de la Pradilla, R.
Tetrahedron Lett. 1985, 25, 5381-5384. (d) Marino, J . P.; Bogdan,
S.; Kimura, K. J . Am. Chem. Soc. 1992, 114, 5566-5572. (e) Marino,
J . P. Pure Appl. Chem. 1993, 65, 667-674.
Our research efforts have focused on the chemistry of
sulfinyl dienes; we were intrigued by the possibility that
for appropriately substituted sulfinyl dienes, allylic
strain8 might control the diastereofacial complexation of
a coordinatively unsaturated metal fragment. For cata-
lytic processes, diastereoselective complexation of this
type could be the primary event which would control the
diastereoselectivity of projected intramolecular metal-
mediated cycloisomerizations.9 Alternatively, the use of
stoichiometric amounts of complexing agent should pro-
vide enantiopure metal-sulfinyl diene complexes suitable
for further diastereoselective transformations.
(5) (a) Solladie´, G.; Lohse, O. J . Org. Chem. 1993, 58, 4555-4563.
(b) Solladie´, G.; Maestro, M. C.; Rubio, A.; Pedregal, C.; Carren˜o, M.
C.; Garc´ıa-Ruano, J . L. J . Org. Chem. 1991, 56, 2317, and references
therein.
(6) Hegedus, L. S. Transition Metals in the Synthesis of Complex
Organic Molecules; University Science Books: Mill Valley, CA, 1994.
(7) (a) Hiroi, K.; Arinaga, Y. Tetrahedron Lett. 1994, 35, 153-156;
Hiroi, K.; Onuma, H.; Arinaga, Y. Chem. Lett. 1995, 1099-1100. (b)
Villar, J . M.; Delgado, A.; Llebar´ıa, A.; Moreto´, J . M.; Molins, E.;
Miravitlles, C. Tetrahedron 1996, 52, 10525-10546. (c) Hua, D. H.;
Lagneau, N. M.; Chen, Y.; Robben, P. M.; Clapham, G.; Robinson, P.
D. J . Org. Chem. 1996, 61, 4508-4509. (d) Ibbotson, A.; Reduto dos
Reis, A. C.; Saberi, S. P.; Slawin, A. M. Z.; Thomas, S. E.; Tustin, G.
J .; Williams, D. J . J . Chem. Soc., Perkin Trans. 1 1992, 1251-1259.
(e) Pe´rez-Encabo, A.; Perrio, S.; Slawin, A. M. Z.; Thomas, S. E.;
Wierzchleyski, A. T.; Williams, D. J . J . Chem. Soc., Perkin Trans. 1
1994, 629-642. (f) Davies, S. G.; Loveridge, T., Clough, J . M. Synlett
1997, 66-68.
(8) For a review: Hoffman, R. W. Chem. Rev. 1989, 89, 1841-1860.
S0022-3263(97)00693-2 CCC: $14.00 © 1997 American Chemical Society

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6327
Sch em e 1
proaches to 2-sulfinyl dienes via base-induced elimination
of 2-sulfinyl allylic bromides, though the extent of
competing reactions was highly substrate dependent.
Furthermore, the diene substitution patterns were some-
what narrow in scope; for instance, alkyl substitution at
C1 of the diene was not reported.
If we were to develop the chemistry of sulfinyl dienes
in a manner which would ultimately lead to diastereo-
selective transformations, it was clear a different ap-
proach that would allow for the formation of stereopure
isomers (cis as well as trans) was necessary. Further-
more, we would require a method which would provide
an opportunity to place substituents at any position along
the diene system if desired. In this paper we summarize
our efforts to prepare a variety of enantiomerically pure
sulfinyl dienes, and we demonstrate that for some of
these substrates, highly diastereofacial complexation
with an iron tricarbonyl fragment is indeed possible.
Resu lts a n d Discu ssion
Syn th esis of En a n tiop u r e (1E)- a n d (1Z)-1-Su lfi-
n yl Dien es a n d 1-Su lfin yl En yn es. We envisioned
that one highly stereocontrolled approach to enantiopure
(E)- or (Z)-1-sulfinyl dienes would be via coupling chem-
istry between stereodefined vinyl-metal and vinyl halide
partners (Scheme 1). In fact, Farina12 had demonstrated
that this was possible, but his Stille-based approach
using vinyl triflates and an (E)-2-stannyl vinyl sulfoxide
had been undertaken using only racemic sulfoxides
(obtained by oxidation of the corresponding sulfides) and
had not been developed in order to accommodate the
synthesis of (1Z)-isomers. Therefore we reasoned that
our approach would only be feasible if the (E)- or (Z)-2-
halo or 2-stannyl vinyl sulfoxide coupling partner could
be prepared in homochiral form. Fortunately, we were
aware of procedures13 for the synthesis of the enantiopure
(E)-2-stannyl vinyl sulfoxide 1 and its 2-bromo vinyl
sulfoxide derivative 2a from (E)-1,2-bis(tri-n-butylstan-
nyl)ethene. However, an approach toward the comple-
mentary (Z)-2-stannyl or 2-halo isomer was unknown,
and we thus chose to direct our initial attention toward
its synthesis.
F igu r e 1. Prior noteworthy approaches to enantiopure sulfi-
nyl dienes.
At the onset of our research program there were sev-
eral procedures available for the synthesis of enantiopure
sulfinyl dienes; however, these were unfortunately either
limited in scope or not highly stereoselective (Figure 1).10
For example, enal homologation by means of a Wad-
sworth-Emmons reaction using a sulfinyl phosphonate11
was reported by Burke10a to proceed with only a modest
7:3 stereoselectivity, favoring the (1E,3E)-1-sulfinyl diene
isomer. Solladie´ and Garc´ıa-Ruano10b had developed
methodology to prepare sulfinyl dienes in a stereospecific
manner; however, this approach was also restricted to
the (1E,3E) isomer. Finally, Maignan10c described ap-
(9) (a) Wender, P. A.; Ihle, N. C. J . Am. Chem. Soc. 1986, 108, 4678.
Wender, P. A.; Ihle, N. C. Tetrahedron Lett. 1987, 28, 2451. Wender,
P. A.; J enkins, T. E. J . Am. Chem. Soc. 1989, 111, 6432. (b) Takacs,
J . M.; Zhu, J . J . Org. Chem. 1989, 54, 5193-5195. (c) J olly, R. S.;
Luedtke, G.; Sheehan, D.; Livinghouse, T. J . Am. Chem. Soc. 1990,
112, 4965.
(10) (a) Burke, S. D.; Shankaran, K.; Helber, M. J . Tetrahedron Lett.
1991, 32, 4655-4658. (b) Solladie´, G.; Ruiz, P.; Colobert, F.; Carren˜o,
M. C.; Garc´ıa-Ruano, J . L. Synthesis 1991, 1011-1012. (c) Bonfand,
E.; Gosselin, P.; Maignan, C. Tetrahedron: Asymmetry 1993, 4, 1667-
1676.
J udging from the ample precedence2,5 that halogenated
Lewis acids readily coordinate to the sulfinyl oxygen, we
reasoned that this interaction could help deliver a halide
in a stereospecific manner to an alkynyl sulfoxide. Using
enantiopure sulfinylethyne 314 (Scheme 2), several Lewis
acids were screened; no reaction was observed upon
(12) Farina, V.; Hauck, S. I. J . Org. Chem. 1991, 56, 4317-4319.
(13) Paley, R. S., Ph.D. Thesis, University of Michigan, 1987. This
procedure was published after the onset of the current work: Marino,
J . P.; Laborde, E.; Deering, C. F.; Paley, R. S.; Ventura, M. P. J . Org.
Chem. 1994, 59, 3193-3201.
(11) (a) Goldmann, S.; Hoffmann, R. W.; Maak, N.; Geueke, K.-J .
Chem. Ber. 1980, 113, 831-844. (b) Mikolajczyk, M.; Midura, W.;
Grzejszczak, S.; Zatorski. A.; Chefczynska, A., J . Org. Chem, 1978, 43,
473-478.

6328 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
Ta ble 1. P a lla d iu m -Ca ta lyzed Syn th esis of
En a n tiom er ica lly P u r e )1E)-Su lfin yl Dien es
Sch em e 2
%
entry sulfoxide R1
R2
R3 conda product yield
1
2
3
4
5
6
7
8
9
2a
2a
H
H
H
H
Me
EtO
H
H
H
H
H
H
H
Me
H
A
A
B
A
B
B
A
A
A
B
A
7a
7b
7c
7d
7e
7f
7g
7h
7i
8
87
87
60
80
80
83
85
61
83
68
71
Ph
Bu
Me
H
2b
2a
2b
2b
2a
H
H
H
CH(OEt)2
CH(OEt)2 Me
b
d
e
2a
2a
H
d
e
treatment of benzene solutions of 3 with HgCl2 or CdBr2
at room temperature. However, use of MgBr2 provided
the desired (Z)-2-bromo vinyl sulfoxide 4a in a modest
35% yield.15 In order to optimize this conversion we
considered the use of zinc halides; with good solubility
in organic solvents and high oxophilicity required for
coordination to the sulfinyl oxygen, this seemed to be an
excellent option. Indeed, treatment of a THF solution
of 3 with ZnI2 provided the corresponding (Z)-2-iodo vinyl
sulfoxide 4b in a 50% yield. Further optimization, using
3 equiv of ZnI2 and benzene as the solvent improved the
procedure to afford 4b in 87% yield after 15 h. The
corresponding bromide 4a and chloride 4c were prepared
in a similar manner, from ZnBr2 (30 h) and ZnCl2 (72 h),
respectively.
Encouraged by these results, we next sought to explore
the synthesis of more substituted analogs. Unfortu-
nately, utilization of 1-sulfinyl-1-hexyne 5a 14 as described
above (rt or refluxing PhH) did not provide any of the
desired iodo vinyl sulfoxide. At this stage we became
aware of the report by Marek16a of a related transforma-
tion using NaI in AcOH to prepare (Z)-iodo vinyl car-
boxylates. These conditions proved to be readily adapt-
able to our needs, as iodovinyl sulfoxide 6a was obtained
in high yield17 (Scheme 2); the phenyl-substituted analog
6b was prepared as well. Unsubstituted analog 4b could
also be prepared in this manner (rt, 90 min, 87%). We
have since modified this procedure to avoid the use of
acetic acid as a solvent; CH3CN is now used instead, with
acetic acid present in only stoichiometric amounts (see
Experimental Section for details).
10
11
2bc
2a c
d
e
9
a
Reaction conditions: Method A: vinylstannane (1.0-1.2 equiv),
Pd2(dba)3‚CHCl3 (2 mol %), PPh3 (8 mol %), refluxing THF, 0.5 to
2 h. Method B: Reaction conditions: vinylstannane (1.0-1.2
b
equiv), Pd(CH3CN)2Cl2 (2 mol %), DMF, rt, 15 min to 3 h. 4-
(1,3-Dithiolan-2-yl)-butyl. c 2 equiv used.
(E)-Bis(tri-n-butyl-
d
stannyl)ethene. e Allyl tri-n-butylstannane.
unfeasible, and due to the expected oxophilicity (and thus
sulfoxide group incompatibility) of corresponding boron,
aluminum, and zirconium reagents, we decided to focus
our efforts on vinyl stannanes as coupling partners19 for
halovinyl sulfoxides 2 and 4. This proved to be a
judicious choice, as we were able to establish conditions
for the coupling of vinyl tri-n-butylstannane with (E)-
bromovinyl sulfoxide 2a ; dienyl sulfoxide 7a was pro-
duced in excellent yield using Pd2(dba)3‚CHCl3 (2 mol %)
and PPh3 (8 mol %) in refluxing THF (Table 1).20 The
generality of the new methodology was then tested by
performing the coupling reaction with a variety of vinyl
stannanes.21 Significantly, the optical rotations of prod-
ucts 7b and 7d were virtually identical to those reported
by Solladie´10b for the same compounds which had been
synthesized by a different route.22 This evidence is
confirmation that the optical purity of the sulfoxide is
not compromised by the coupling process reported here.
It should also be noted that use of allyl tri-n-butylstan-
nane provided the “skipped” sulfinyl diene 9, in high yield
(Table 1, entry 11), and that a bis-coupling, to produce
bis-sulfinyl triene 8, was also possible.
With both (E)- and (Z)-halovinyl sulfoxide isomers in
hand, we then sought a suitable vinylic metal coupling
partner in order to achieve the desired stereocontrolled
synthesis of 1-sulfinyl dienes. Preliminary investigations
utilizing organocuprates with iodovinyl sulfoxide 4b were
not fruitful; neither divinylcuprate nor the corresponding
cyanocuprate afforded the desired 1-sulfinyl dienes.18
Because coupling with vinyl cuprates had proven to be
(18) Treatment of 4b with divinylcuprate (derived from commercially
available vinylmagnesium bromide) afforded a 62:38 mixture of (1Z)-
and (1E)-sulfinyl dienes (in a 1.6:1 ratio) and sulfinylethene. Treat-
ment with the corresponding cyanocuprate afforded (Z)-2-cyano-1-
sulfinylethene (25%) and unreacted 4b (65%).
(19) (a) Farina, V.; Krishnamurthy, V.; Scott, W. J . Org. React. 1997,
50, 1-652. (b) Farina, V.; Roth, G. P. Adv. Metal-Org. Chem. 1996, 5,
1-53. (c) Mitchell, T. N.; Synthesis 1992, 803-815. (d) Stille, J . K.;
Groh, B. L. J . Am. Chem. Soc. 1987, 109, 813-817. (e) Stille, J . K.
Angew. Chem., Int. Ed. Engl. 1986, 25, 508-524 and references
therein.
(20) Stereochemical and configurational homogeneity of 7a was
established by examination of the 1H NMR spectrum of the crude
reaction mixture at 300 MHz and analysis of the 1H NMR spectrum
of the purified material in the presence of Eu(hfc)3.
(21) See ref 57b for references which describe the synthesis of
commercially unavailable vinyl stannanes. For the stannane used to
prepare 10g, see: Hutzinger, M. W.; Oehlschlager, A. C. J . Org. Chem.
1995, 60, 4595-4601. For the stannane used to prepare 10h , 10i, and
10l, see: Barrett, A. G. M.; Barta, T. E.; Flygare, J . A. J . Org. Chem.
1989, 54, 4246-4249.
(22) Optical rotation data: 7b: [R]D ) +225.0, c 0.44, acetone; [lit.:
10b [R]D ) +225.1, c 0.82, acetone]. 7d : [R]D ) +218.6, c 1.06, acetone;
[lit.:10b [R]D ) +216.1, c 0.74, acetone]).
(14) Kosugi, H.; Kitaoka, M.; Tagami, K.; Takahashi, A.; Uda, H. J .
Org. Chem. 1987, 52, 1078-1082.
(15) The (Z)-stereochemistry of 4a was readily verified by 1H NMR;
the vinylic proton coupling constant of 6.7 Hz was consistent with cis
stereochemistry.
(16) (a) Marek, I.; Alexakis, A.; Normant, J .-F. Tetrahedron Lett.
1991, 32, 5329-5332. Marek, I.; Meyer, C.; Normant, J .-F Org. Synth.
1996, 74, 194-204. See also: (b) Ma, S.; Lu, X.; Li, Z. J . Org. Chem.
1992, 57, 709-713. (c) Ma, S.; Lu, X. Org. Synth. 1993, 72, 112-115.
(17) The structure of 6a was verified by an NOE experiment:
irradiation of the vinyl proton at 6.6 ppm resulted in a 2.0% enhance-
ment for the allylic methylene at 2.6 ppm.

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6329
Ta ble 2. P a lla d iu m -Ca ta lyzed Syn th esis of
En a n tiom er ica lly P u r e (1Z,3E)-Su lfin yl Dien es
Ta ble 3. Syn teh sis of En a n tiom er ica lly P u r e
(1E,3E)-Su lfin yl Dien es via Ca r bocu p r a tion of Alk yn yl
Su lfoxid es
entry
sulfoxide
E+
X
product
% yield
%
1
2
3
4
5
5
12
13
aqueous workup
NIS (4 equiv)
aqueous workup
aqueous workup
H
I
H
H
14a
14b
14c
14d
93
65
80
47
entry sulfoxide
R
R1
R2
R3 product yielda
1
2
3
4
5
6
7
8
9
10
11
12
13
14
4b
4b
4b
4b
4b
4b
4b
4b
4b
6a
6a
6a
6b
4bb
H
H
H
H
H
H
H
H
H
H
H
Me
H
H
10a
10b
10c
10a
10e
10f
10g
10h
10i
10j
10k
10l
10m
11
91
80
91
83
76
75
77
87
89
80
92
68
89
83
Me
H
EtO
H
H
Me
H
isomerization (vinyl tributylstannane, 1 equiv; Pd2(dba)3‚
CHCl3, 2 mol %; PPh3, 8 mol %; THF, reflux); after 1 h,
ca. 30% of the cis double bond had been converted into
the trans isomer. When this experiment was repeated
without vinyl stannane, the result was identical; how-
ever, when the palladium catalyst was also omitted, no
isomerization took place. The possibility that adventi-
tious acid caused the double bond isomerization was
seemingly excluded by repeating the experiment using
Pd2(dba)3‚CHCl3 and PPh3 with added diisopropylethy-
lamine (20 mol %); isomerization still took place as before.
To rule out that high temperature (refluxing THF vs
DMF at room temperature) played a role in the isomer-
ization, 10a was treated with Pd(CH3CN)2Cl2 and the
vinyl stannane in DMF at 80 °C; no isomerization was
observed. As a result of these experiments, we now
speculate that the isomerization of the cis double bond
was a result of conjugate addition of PPh3 to the vinyl
sulfoxide, rotation of the intermediate zwitterionic spe-
cies, and ejection of PPh3.26 Presumably the palladium
catalyst coordinates to the sulfinyl oxygen, thereby
activating the system toward nucleophilic attack.
It did not escape our attention that our approach to
(1E)-sulfinyl dienes suffered one severe limitation: it
would be impossible to prepare 2-alkyl-substituted (1E)-
sulfinyl dienes. Since (E)-2-halovinyl sulfoxides 2 were
derived from (E)-1,2-bis(tri-n-butylstannyl)ethene,27 adapt-
ing this approach to the synthesis of the more substituted
analog would require regiospecific transmetalation of the
unknown 1,2-bis(tri-n-butylstannyl)-1-alkenes. Thus we
turned to a different approach to install substituents in
the 2-position. It had been previously demonstrated14,28
that alkylcopper reagents (e.g., MeCu, BuCu) add to
alkynyl sulfoxides regio- and stereospecifically to afford
vinyl sulfoxides in high yield. We reasoned that sulfinyl
dienes could be obtained if vinyl copper reagents were
to be employed in an analogous manner. Indeed, this
goal was readily accomplished, as shown in Table 3.
Furthermore, we demonstrate here that the presumed
1-sulfinylvinyl copper intermediate can be trapped with
an electrophile other than proton. Introduction of an
iodine atom (Table 3, entry 2, 14b) could in principle
allow for further manipulation of this sulfinyl diene.
With methodology now available for controlling the
stereochemistry of the 1,2-double bond, we next sought
a procedure that would allow for access to the isomers
CH(OEt)2
CH(OEt)2 Me
CH2OH
H
H
Bu
H
H
H
H
H
H
H
c
CH2OH CH2OTBS
CH2OH CH2OTIPS
H
Bu
Bu
H
H
H
Ph
Bu CH2OH CH2OTBS
Ph
c
H
c
H
c
a
Reaction conditions: vinylstannae (1.0-1.2 equiv), Pd(CH3CN)2-
Cl2 (2 mol %), DMF, rt, 15 min to 3 h. 2 equiv used. c(E)-Bis(tri-
b
n-butylstannyl)ethene.
Our next goal was to effect the analogous transforma-
tion using (Z)-iodovinyl sulfoxide 4b in order to establish
a stereocontrolled route to the more challenging (1Z,3E)-
1-sulfinyl dienes. Surprisingly, the identical reaction
conditions that successfully produced 7a were instead
nonstereospecific; sulfinyl diene 10a was obtained as a
(1Z)/(1E) mixture in an 82:18 ratio. Fortunately, the use
of “ligandless” conditions23 (Pd(CH3CN)2Cl2, 2 mol %,
DMF) afforded (1Z,3E)-1-sulfinyl diene 10a in excellent
yield and with complete retention of double bond stereo-
chemistry. This stereospecific coupling was repeated
with a number of other vinyl stannanes21 (Table 224) and
could also be performed with trisubstituted iodovinyl
sulfoxides 6a or 6b to prepare the first examples of
(1Z,3E)-2-alkyl-1-sulfinyl dienes (10j-m ). It should also
be noted that these “ligandless” conditions can be em-
ployed to cleanly couple vinyl stannanes to (E)-iodovinyl
sulfoxide 2b as well (Table 1, entries 3, 5, 6, and 10),
with complete stereospecificity. An apparent limitation
to our methodology is our inability to effect coupling of
4b with methyl (E)-2-stannyl acrylate. Finally, we have
been unable to effect coupling of vinyl halides to (E)-
stannylvinyl sulfoxide 1 under either set of conditions
described above.25
We were intrigued by the loss of stereospecificity in
the attempted coupling of (Z)-iodovinyl sulfoxide 4a using
the Pd2(dba)3‚CHCl3/PPh3/THF system, and thus we
carried out several experiments in order to gain an
understanding of the mechanism of this process. (1Z,3E)-
1-Sulfinyl diene 10a was resubmitted to the same reac-
tion conditions which had given rise to the double bond
(23) Beletskaya, I. P. J . Organomet. Chem. 1983, 250, 551.
(24) (1Z)-1-Sulfinyl dienes 10g,h ,i are obtained as 30-35:1 mixtures
containing minor amounts of the (1E) isomers which can be readily
removed by silica gel chromatography. The origin of this slight loss
of stereoselectivity would appear to be in the Stille coupling process;
however, the mechanism by which it occurs remains unclear.
(25) See ref 4e for an example of coupling involving an aryl iodide
and stannylvinyl sulfoxide 1. We have only been able to effect a
coupling between stannylvinyl sulfoxide 19 and p-nitrophenyl io-
dide to afford the corresponding 1-sulfinyl styrene derivative in a 39%
yield.
(26) This process would be reminiscent of those reported by Trost:
Trost, B. M.; Li, C.-J . J . Am. Chem. Soc. 1994, 116, 3167-3168 and
10819-10820.
(27) (a) Corey, E. J .; Wollenburg, R. H. J . Org. Chem. 1975, 40,
2265-2266. (b) Corey, E. J .; Wollenburg, R. H. J . Am. Chem. Soc.
1974, 96, 5581-5583. (c) Bottaro, J . C.; Hanson, R. N.; Seitz, D. E. J .
Org. Chem. 1981, 46, 5221-5222.
(28) Truce, W. E.; Lusch, M. J . J . Org. Chem. 1978, 43, 2252-2258.

6330 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
Ta ble 4. Syn th esis of En a n tiom er ica lly P u r e
Ta ble 5. Syn th esis of En a n tiom er ica lly P u r e
(Z)-1-Su lfin yl-1-en -3-yn esa
(E)-1-Su lfin yl-1-en -3-yn esa
entry
R
product
% yield
entry
R
product
% yield
1
2
3
4
CH2OH
Bu
(CH2)3OTBS
SiEt3
15a
15b
15c
15d
84
84
86
87
1
2
3
4
5
6
7
Bu
17a
17b
17c
17d
17e
17f
17g
77b
74b
75
87
82
(CH2)4O-t-Bu
CH2OTBS
SiEt3
CH(OEt)2
H
a
Reaction conditions: 2a (1 equiv), alkyne (1.2 equiv), DBU (2
equiv), Pd(PPh2)4 (5 mol %), CuI (30 mol %), benzene, rt, 40 min.
60
66
Ph
a
containing a (3Z)-double bond. Since at the onset of this
work there were no general preparations for cis-vinyl
stannanes,29 we envisioned an approach which would
involve syn-reduction of previously unknown enantiopure
enynyl sulfoxides. We judged that the most rapid entry
into these systems, and one that would avoid stannane
synthesis, would involve use of the Sonogashira meth-
odology30 to couple alkynes to halovinyl sulfoxides 2 or
4. Indeed, there was a clear precedence that electron-
deficient vinyl halides could participate in this transfor-
mation in the presence of a hindered base.31 Our own
results corroborated this requirement;32 optimal yields
of (E)-1-sulfinyl enyne 15a were ultimately obtained
when 2 equiv of the non-nucleophilic base DBU was
added to the reaction mixture (in benzene). This reaction
also proved to be general for a number of functionalized
alkynes; the results are summarized in Table 4. To
demonstrate that (E)-1-sulfinyl enynes could serve as
precursors for (1E,3Z)-1-sulfinyl dienes, 15a and 15b
were cleanly hydrogenated to 16a and 16b using H2 and
RhCl(PPh3)3 (10 wt %) in benzene (eq 1). The cis
stereochemistry of the new double bond in each new
sulfinyl diene was confirmed by analysis of the individual
1H NMR spectra.33
Reaction conditions: 4b (1 equiv), stannylalkyne (1.2 equiv),
b
Pd(CH3CN)2Cl2 (2 mol %), DMF, rt, 30 min to 1 h. Reaction
performed in 95:5 DMF/THF.
Sch em e 3
foxide 4b to couple to any alkyne, regardless of choice of
palladium catalyst or amine base, led to its complete
decomposition. Though we are still unable to provide an
explanation, we could readily overcome this complication
by use of Stille methodology. Alkynylstannanes coupled
to 4b under the “ligandless” conditions just as readily as
vinylstannanes had, affording (Z)-1-sulfinyl enynes 17
(Table 5). For alkynes that demonstrated a poor solubil-
ity in DMF, THF was employed as a cosolvent (DMF/
THF, 95:5) in order to obtain comparable yields. While
we were able to overcome the problem of preparation of
these (Z)-1-sulfinyl enynes, we have been unable to
successfully hydrogenate them to obtain the correspond-
ing (1Z,3Z)-1-sulfinyl dienes. Attempted hydrogenation
of 17a with Wilkinson’s catalyst led to the formation of
a complicated mixture of 17a and overreduced products,
while use of Lindlar’s catalyst (in benzene) or Pd/BaSO4
(in pyridine) resulted only in recovery of the sulfinyl
enyne.
Syn th esis of En a n tiop u r e (1E)- a n d (1Z)-2-Su lfi-
n yl Dien es. We next sought to extend our approach in
order to prepare enantiopure 2-sulfinyl dienes. At first
glance, preparation of the simplest analog, 2-sulfinyl
butadiene 29a , seemed straightforward; the previously
known34 1-bromovinyl sulfoxide would be coupled to vinyl
tri-n-butylstannane under the conditions described above
for the synthesis of (E)-1-sulfinyl dienes. As it turned
out the 1-bromovinyl sulfoxide was remarkably resistant
to coupling, as all efforts to effect this transformation
failed to provide more than traces of 2-sulfinyl diene 29a .
Reasoning that the corresponding iodide would be more
reactive, we developed two approaches to prepare this
previously unknown compound (Scheme 3). First, (R)-
vinyl p-tolyl sulfoxide was regiospecifically converted to
its iodohydrin;35 mesylation of the diastereomeric alcohols
followed by DBU-induced elimination afforded 1-iodovi-
Though the Sonogashira coupling smoothly afforded
(E)-1-sulfinyl enynes, attempts to replicate this procedure
in order to prepare the corresponding (Z) isomers were
unsuccessful. All attempts to induce (Z)-iodovinyl sul-
(29) Reports on the synthesis of (Z)-vinylstannanes have recently
been published: (a) Lipshutz, B. H.; Keil, R.; Barton, J . C. Tetrahedron
Lett. 1992, 33, 5861-5864; (b) Asao, N.; Liu, J .-X.; Sudoh, T.;
Yamamoto, Y. J . Org. Chem. 1996, 61, 4568-4571; (c) Nakamura, E.;
Imanishi, Y.; Machii, D. J . Org. Chem. 1994, 59, 8178-8186.
(30) (a) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett.
1975, 16, 4467-4470. (b) Ratoveloma, V.; Linstrumelle, G. Tetrahe-
dron Lett. 1981, 22, 315-318.
(31) Schreiber had successfully coupled a terminal alkyne with
methyl (E)-3-iodo acrylate using the “standard” cocatalysts Pd(PPh3)4
and CuI, but with triethylamine as the solvent. Presumably the
hindered base was employed to suppress addition-elimination side
reactions. Schreiber, S. L.; Kiessling L. L. J . Am. Chem. Soc. 1988,
110, 631-633. See also: Myers, A. G.; Alauddin, M. M.; Fuhry, M.
M.; Dragovich, P. S.; Finney, N. S.; Harrington, P. M. Tetrahedron Lett.
1989, 30, 6997-7000.
(32) The attempted coupling of propargyl alcohol to 2a in diethy-
lamine [with Pd(PPh3)4 (5 mol %) and CuI (30 mol %)] completely failed.
While use of benzene as the solvent gave disappointing product yields
of 20 to 30%, an improvement to 54% was realized using 4:1 benzene/
triethylamine as the solvent.
(33) After performing the required decoupling experiments, J H3-H4
was determined to be 11.0 Hz and 10.8 Hz for 16a and 16b, confirming
the cis stereochemistry of the 3,4-double bond of each compound.
(34) Cardellicchio, C.; Fiandanese, V.; Naso, F.; Scilimati, A. Tet-
rahedron Lett. 1992, 33, 5121-5124.
(35) The iodohydrin was obtained as a 6:1 mixture of diastereomers
which were inseparable by column chromatography.

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6331
Ta ble 6. Syn th esis of En a n tiop u r e 2-Su lfin yl Dien es
Sch em e 4
entry sulfoxide
R
R1 R2 methoda product % yield
1
2
3
4
5
6
7
18
22
22
24
24
27
28
H
H
H
H
Bu
Bu
c
H
A
B
B
C
B
C
C
29a
29b
29c
29d
29e
29f
29g
70
89
77
75
59
59
81
H
Ph
H
b
H
H
Bu
Bu
H
H
H
Bu Me
a
Reaction conditions: A: Pd(CH3CN)2Cl2 (2 mol %) BHT (1
equiv), DMF, rt, 2 h. B: Pd2(dba)3‚CHCl3 (5 mol %), AsPh3 (20
mol %), BHT (1 equiv), THF, rt, 2 h. C: Pd2(dba)3‚CHCl3 (5 mol
Sch em e 5
b
%), AsPh3 (20 mol %), BHT (1 equiv), THF, ∆, 2 h. (EtO)2CH.
c PMBO(CH2)4.
nyl sulfoxide 18 in an excellent overall yield. Alterna-
tively, sulfinyl ethyne 314 was treated with Bu3SnH in
benzene36 to regiospecifically provide the 1-stannylvinyl
sulfoxide 19 which was then readily converted to 18 using
NIS.
As expected, 18 did prove to be a more reactive
coupling partner with vinyltri-n-butylstannane, though
the improvement in yield was only modest (25-35%).
Again, a variety of conditions were tested: Pd(CH3CN)2Cl2,
in DMF or NMP, rt to 100 °C; Pd2(dba)3‚CHCl3 with PPh3
or AsPh3,37 in THF (rt to ∆) or NMP (rt to 100 °C).
Fortunately 29a was at last obtained in an acceptable
yield (70%) with Pd(CH3CN)2Cl2 (DMF, rt) when the
radical inhibitor BHT was included as an additive (Table
6, entry 1).38 Optical rotation data measured for 29a
again established that the optical integrity of the sul-
foxide was not compromised by the palladium-catalyzed
coupling processes reported herein.39
subsequent coupling to vinyl stannanes was straightfor-
ward. In these cases, the (1E)-2-sulfinyl dienes 29b and
29c were best obtained with a Pd2(dba)3/AsPh3/BHT/THF
system (Table 6).
Extending this approach to more substituted 2-sulfinyl
dienes also proved to be feasible and relied on our ability
to prepare the required iodovinyl sulfoxide coupling
partners with a high degree of regio- and stereoselectiv-
ity. Initally we attempted to trap R-lithiovinyl sulfoxides
(obtained by LDA treatment of (E)-vinyl sulfoxides at -78
°C in THF) with I2 or CI4, but the desired iodovinyl
sulfoxides were produced in poor yields (<40%). After
an unsuccessful attempt to extend the iodohydrin/mesy-
lation/elimination sequence to prepare a more substituted
analog of 18, we began to investigate hydrostannylations
of readily available alkynyl sulfoxides. First, to prepare
(1E)-2-sulfinyl dienes, an anti hydrostannylation as first
reported by Leusink36 was required. Using hexane as a
solvent, we were able to regio- and stereoselectively
convert alkynyl sulfoxide 5 into its stannylvinyl sulfoxide
derivative 20, accompanied by a minor amount of its syn-
hydrostannylation product 21 (Scheme 4). After routine
separation and purification of 20 by silica gel chroma-
tography, conversion to the corresponding iodide41 22 and
Next, preparation of the isomeric (1Z)-2-sulfinyl dienes
would require the complementary syn-hydrostannylation
process. While the palladium-catalyzed hydrostannyla-
tion procedure of Guibe´42a had been shown to be a
predominantly syn-process for electron poor alkynes, the
exact ratio of product isomers was rather substrate
dependent. Indeed, in the only prior report of an ap-
plication of this process with alkynyl sulfoxides, the 2:1
regioisomeric mixture of 1- and 2-stannylvinyl sulfoxides
reported by Magriotis43 was not particularly encouraging.
Nevertheless, when alkynyl sulfoxide 514 was subjected
to these conditions (Bu3SnH, 2 mol % Pd(PPh3)4, toluene,
rt), 1-stannylvinyl sulfoxide 21 was obtained as a 6:1
regioisomeric mixture. Remarkably, when the same
reaction was performed at low temperature (-78 °C to
rt over 3 h), this ratio improved to 40:1 (Scheme 5)!
Again, the isomers were readily separated by chroma-
tography, and after conversion to iodide 24 and coupling
with vinyl tri-n-butylstannane, (1Z)-2-sulfinyl diene 29d
was obtained in good yield. The generality of this
reaction sequence was illustrated by the preparation of
functionalized analog 29f (Table 6).
(36) Leusink, A. J .; Budding, H. A.; Drenth, W. J . Organometallic
Chem. 1967, 9, 295-306.
(37) Farina, V.; Krishnan, B. J . Am. Chem. Soc. 1991, 113, 9585-
9595.
(38) For recent uses of BHT in Stille coupling processes, see ref 19a
and Stork, G.; Issacs, R. C. A. J . Am. Chem. Soc. 1990, 112, 7399-
7400.
(39) The optical rotation data measured for 29a ([R]D ) +168, c 1.79,
EtOH) was within experimental error of the literature value (lit.40 [R]D
) +174, c 2.0, EtOH) and was independent of the sequence of reactions
used to prepare iodovinyl sulfoxide 18.
(41) For other applications of enantiopure R-halovinyl sulfoxides,
see Mikolajczyk, M.; Krysiak, J . A.; Wieczorek, M. W.; Blaszcyk, J .
Tetrahedron: Asymmetry 1996, 7, 3513-3520 and references therein.
(42) (a) Zhang, H. X., Guibe´, F., Balavoine, G. J . Org. Chem. 1990,
55, 1857-1867. See also: (b) Ichinose, Y.; Oda, H.; Oshima, K. Bull.
Chem. Soc. J pn. 1987, 60, 3468-3470. (c) Miyake, H.; Yamamura, K.
Chem. Lett. 1989, 981-984.
(40) Bonfand, E.; Gosselin, P.; Maignan, C. Tetrahedron Lett. 1992,
33, 2347-2348. See also ref 10c.
(43) Magriotis, P. A., Brown, J . T., Scott, M. E. Tetrahedron Lett.
1991, 32, 5047-5050.

6332 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
synthesis of iron(0) tricarbonyl complexes of racemic
sulfinyl dienes; however, the diastereoselectivity of these
complexations was not discussed.48
Our earliest experiments used the method of Shvo and
Hazum49 to prepare the sulfinyl iron(0) diene complexes.
This approach, using Fe(CO)5 and N-methyl morpholine
N-oxide (NMO), afforded the target complexes in modest
to good yields. However, as we tested more highly
substituted sulfinyl dienes, yields of the corresponding
Fe(CO)3 complexes began to decrease to 20-30%. For
these substrates, we found it convenient to use an excess
F igu r e 2. NOE data for sulfinyl diene 29g.
Finally, we briefly explored the possibility of introduc-
ing two 1-alkyl substituents into the 2-sulfinyl diene
system via a carbocupration-iodination sequence. As
demonstrated earlier (Table 3, entry 2) organocopper
reagents can add to alkynyl sulfoxides regio- and ste-
reospecifically, and the presumed 1-sulfinylvinyl copper
intermediate can be trapped with iodine. Introduction
of iodine was in fact vital to our approach in order to
provide entry into a substrate which would be suitable
for coupling to vinyl stannanes. This proved to be a
useful method, as sequential treatment of alkynyl sul-
foxide 5 with methyl copper and NIS provided the fully
substituted 1-iodovinyl sulfoxide 28 in an acceptable yield
of 61% (eq 2). Coupling of 28 to vinyl tri-n-butylstannane
proceeded smoothly, affording the fully substituted 2-sulfi-
50
of (bda)Fe(CO)3 (4 equiv) in order to effect the desired
complexation in high yield. Because this iron tricarbonyl
transfer reagent is not commercially available and be-
cause it was necessary to employ an excess of reagent to
drive the complexation to completion, we routinely
recovered as much of the excess (bda)Fe(CO)3 as possible
during chromatographic purification of the reaction
product. Typically, 70 to 80% of the excess 3 equiv of
(bda)Fe(CO)3 can be recovered and reused. Complexation
under these conditions is apparently kinetically con-
trolled; when the minor diastereomer of sulfinyl iron(0)
diene 30m (entry 17, Table 7) was subjected to treatment
with (bda)Fe(CO)3 (4 equiv, toluene, 45 °C, 16 h), it was
recovered with none of the major diastereomer detected
(by TLC). By comparison, complexation with Fe(CO)5/
NMO appears to be under thermodynamic control; when
the minor diastereomer of sulfinyl iron(0) diene 30g
(entry 11, Table 7) was subjected to these conditions, both
diastereomers as well as the decomplexed sulfinyl diene
7i were observed (by TLC).
The only limitation to the use of (bda)Fe(CO)3 as an
iron tricarbonyl transfer reagent that we have encoun-
tered thus far is its incompatibility with unprotected
alcohol groups. For example, treatment of sulfinyl diene
10g with an excess of (bda)Fe(CO)3 afforded a complex
mixture of products. Unfortunately, neither complex-
ation method could be utilized to effect conversion of
sulfinyl dienes 10f, 10l (or its OTES derivative51), or 14b
into the corresponding sulfinyl iron dienes. For each of
these substrates, the energy barrier for attaining the s-cis
conformation required for complexation of the diene must
simply be too high, and higher temperatures or prolonged
reaction times led only to complex mixtures.
nyl diene 29g (Table 6); the stereochemistry was verified
by NOE experiments, as shown in Figure 2.
Diaster eoselective Syn th esis of En an tiopu r e Su lfi-
n yl Dien e Ir on (0) Tr ica r bon yl Com p lexes. With
access to a diverse array of sulfinyl dienes, we next set
out to determine which, if any, of these substrates would
exhibit diastereoselective complexation upon treatment
with a coordinatively unsaturated metal fragment. The
reported ease of preparation, isolability, and handling of
iron(0) diene complexes44 accounted for our decision to
explore the chemistry of the previously unknown enan-
tiopure sulfinyl diene iron(0) tricarbonyl complexes. It
was our expectation that allylic 1,3-strain8 would restrict
the sulfoxide conformation with respect to the diene; by
forcing the bulky sulfinyl aromatic group into a position
over one of the diene’s diastereotopic faces, the other face
should be available for preferential complexation by the
metal fragment.
Prior to the onset of this work there were only isolated
reports of diastereoselective complexations of an iron
tricarbonyl unit to a diene bearing one or more chiral
centers. Most notable among these was the chiral-aux-
iliary-directed asymmetric complexation described by
Pearson;45 a chiral (E,E)-dienamide prepared from (S)-
2-(diphenylhydroxymethyl)pyrrolidine was complexed
with high diastereoselectivity (>99:1) at ca. 50% conver-
sion. Other examples have included a modestly diaste-
reoselective complexation (75:25) of a diene derived from
L-arabinose46 and the diastereospecific complexation of
cis-1-methyl-2,3-methoxycyclohexa-4,6-diene.47 We were
also aware of a report from 1977 which described the
To evaluate the diastereoselectivity of the complexation
of each sulfinyl diene, the major and minor diastereo-
meric Fe(CO)3 complexes were each purified, and the
ratio was then determined by weight. In every case, the
Rf difference between the major and minor diastereomers
was large enough to make the chromatographic separa-
tion trivial. We were unable to determine diastereomeric
1
ratios in the usual manner using the H NMR spectra of
the crude reaction mixtures; it was impossible to shim
NMR samples of the crude mixtures, presumably as a
result of contamination with paramagnetic iron residues.
Table 7 reveals the yields and diastereomer ratios of
the sulfinyl diene complexations. As we had anticipated,
(46) (a) Schmalz, H.-G.; Hessler, E.; Bats, J . W.; Du¨rner, G.
Tetrahedron Lett. 1994, 35, 4543-4546. (b) Hessler, E.; Schmalz, H.-
G.; Du¨rner, G. Tetrahedron Lett. 1994, 35, 4547-4550.
(47) Howard, P. W.; Stephenson, G. R.; Taylor, S. C. J . Chem. Soc.,
Chem. Commun. 1988, 1603-1604.
(48) Gaoni, Y. Tetrahedron Lett. 1977, 4521-4524.
(49) Shvo, Y.; Hazum, E. J . Chem. Soc., Chem. Commun. 1975, 829-
830.
(50) Alcock, N. W.; Danks, T. N.; Richards, C. J .; Thomas, S. E.
Organometallics 1991, 10, 231-238.
(51) Prepared in a 75% yield from 10l by treatment with TESOTf
and 2,6-lutidine (CH2Cl2, rt).
(44) (a) Gre´e, R.; Lellouche, J . P. Adv. Metal-Org. Chem. 1995, 4,
129-173. (b) Pearson, A. J ., Iron Compounds in Organic Synthesis;
Academic Press: San Diego, 1994.
(45) Pearson, A. J .; Chang, K.; McConville, D. B.; Youngs, W. J .
Organometallics 1994, 13, 4-5. See also references cited therein.

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6333
Ta ble 7. Dia ster eoselective F om r a tion of η4-(1- a n d 2-Su lfin yl d ien e)F e(0)(CO)3 Com p lexes fr om Su bstitu ted
En a n tiop u r e Su lfin yld ien es
those substrates capable of minimal carbon-sulfur bond
rotation as a consequence of allylic 1,3-strain8 are com-
plexed with good to excellent diastereoselectivity (entries
2-4, 8, 9, 16, 17). The absolute stereochemistry of the
major diastereomer of 30e has been determined by X-ray
crystallography of a derived iron dienol; the crystal
structure has been published elsewhere52 and reveals
that the Fe(CO)3 fragment is positioned on the R face,53
anti to the bulky tolyl group of the sulfoxide group. By
analogy, and as a consequence of similar chromato-
graphic polarities,54 the major (less polar) diastereomers
of 30b,c,k ,l,m have been also each assigned as possessing
an R face Fe(CO)3 fragment. We are at this point unable
to explain the diminished selectivities for the complex-
ation of sulfinyl dienes 10g and 10j. For the (1E)-2-alkyl-
1-sulfinyl dienes 14a and 14d which were examined
(entries 13, 14), it was the more polar Fe(CO)3 diene
diastereomer of which predominated. In these cases,
allylic strain also must force the tolyl group into a
preferred conformation which instead is proximal to the
R diene face rather than the â face as observed for the
(1Z)-1-sulfinyl dienes. The marginal selectivity observed
for complexation of 14a and 14d must be a result of the
favored position of the tolyl group: it would be expected
to point away from the diene unit and thus would be too
distant to have a significant impact on the direction of
the approach of the Fe(CO)3 fragment. On the basis of
this argument, and the chromatographic polarity ob-
served for these cases, we are tentatively assigning the
major diastereomer for 30i and 30j as having the Fe(CO)3
fragment positioned on the â face of the diene.
Finally, we found that the (1E)-2-unsubstituted-1-
sulfinyl dienes can be complexed with only marginal
diastereoselectivities. In the absence of a 2-substituent,
it would be expected that this lack of selectivity is a result
of the small calculated energy difference (1.6 kcal/mol)55
between the two conformational minima of such systems,
as pointed out by Hoffmann.8 Assuming that the slightly
lower energy conformation would place the S-O bond in
the plane of the 1,2-double bond, the â diene face would
be somewhat shielded by the sulfoxide tolyl group and
the Fe(CO)3 fragment should prefer, though only margin-
ally, to be positioned on the R diene face. As we have
been unable to obtain satisfactory crystals from these
(1E)-2-unsubstituted-1-sulfinyl iron(0) diene complexes
(52) Paley, R. S.; Rubio, M. B.; Ferna´ndez de la Pradilla, R.; Dorado,
R.; Hundal, G.; Mart´ınez-Ripoll, M. Organometallics 1996, 15, 4672-
4674.
(53) We are defining the diene plane, as drawn in Table 7, as the
separation between the R (lower) face from the â (upper) face.
(54) Clinton, N. A.; Lillya, C. P. J . Am. Chem. Soc. 1970, 92, 3058-
3064. Chromatographic polarities have often been used to make
stereochemical assignments for iron(0) diene complexes. For example,
see: Roush, W. R.; Park, J . C. Tetrahedron Lett. 1990, 31, 4707-4710.
(55) Kahn, S. D.; Hehre, W. J . J . Am. Chem. Soc. 1986, 108, 7399-
7400.

6334 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
Sch em e 6
Sch em e 7
(or any of their derivatives), we are forced to make a
tentative assignment of absolute stereochemistry of the
major diastereomers which is based on the model dis-
cussed above, and, once again, on the chromatographic
polarities. As in the highly diastereoselective cases (for
example, entry 8) where the major iron(0) diene diaster-
eomers were each less polar, the major diastereomers of
30a ,d ,f,g,h were also less polar, suggesting that in each
of these cases the Fe(CO)3 fragment occupied the R diene
face.
Syn th esis of a Su lfin yl Tetr a en e. Among our
objectives was the synthesis of more complex sulfinyl
dienes, especially those that might be suitable for an
investigation of intramolecular Diels-Alder reactions1 or
transition metal catalyzed cycloisomerizations.9 In prin-
ciple the asymmetry of the sulfoxide could be exploited
to control the absolute stereochemistry of the newly
formed stereocenters in these processes. An issue which
needed to be resolved was simply to determine if the
required enantiopure multiply unsaturated sulfoxides
could in fact be prepared through utilization of the
methodology we had developed. We therefore chose (1E)-
1-sulfinyl tetraene 31 as a synthetic target; our success
largely depended on our choice of an appropriately func-
tionalized vinyl stannane to be coupled with bromovinyl
sulfoxide 2a . Stannane 32 was prepared from 1-hexynal
in three steps (Scheme 6); remarkable in this sequence
was the ability to effect lithiation of a vinyl bromide in
the presence of the acidic proton of a dithioacetal.
Sulfinyl diene 7i was readily prepared (entry 8, Table 1)
according to the methodology described herein.
Scheme 7 details the conversion of sulfinyl diene 7i to
the target sulfinyl tetraene 31. After deprotection of 7i
to reveal aldehyde 33, the remaining double bonds were
installed by a modification of Yamamoto’s protocol56 using
the allyl titanate 34 derived from allyltriphenylsilane.
The hydroxysilane 35 was prepared in good yield only in
the presence of ZnBr2, which presumably coordinated to
the sulfinyl oxygen, thus preventing it from coordinating
with the oxophilic titanium reagent 34. (Control experi-
ments without ZnBr2 or without Ti(O-i-Pr)4 gave only
unreacted aldehyde 33). Hydroxysilane 35, a 1:1 mixture
of anti diastereomers, was treated with either catalytic
BF3‚Et2O to give the (8E)-isomer of tetraene 31 (E/Z; 95:
5) or with potassium tert-butoxide to exclusively afford
the (8Z)-isomer.
Con clu sion s
We have successfully demonstrated a number of ste-
reocontrolled approaches to enantiomerically pure sulfi-
nyl dienes based on transition metal (palladium or
copper) mediated chemistry.57 Of the diverse array of
diene substitution patterns which can now be prepared
that incorporate the sulfoxide functionality, the (1Z)-4-
alkyl- and (1Z)-3,4-dialkyl-1-sulfinyl dienes are the best
substrates for the diastereoselective complexation by a
metal carbonyl fragment. Sulfinyl iron (0) tricarbonyl
diene complexes can be prepared in high yield (up to 96%)
and with high diastereoselectivity (up to 16:1) using
Fe(CO)5/NMO or (benzylidene acetone)Fe(CO)3. The
origin of the high diastereoselectivity for the complex-
ation of the (1Z)-1-sulfinyl dienes is likely to be allylic
1,3-strain. We are currently exploring the chemistry of
these sulfinyl iron(0) dienes and will also be investigating
the possibility that the diastereoselective transition metal
mediated cycloisomerizations of the multiply unsaturated
sulfoxides exemplified by sulfinyl tetraene 31 could be
effected using catalytic amounts of iron. These results
will be reported in due course.
Exp er im en ta l Section
Gen er a l Meth od s. All reactions were carried out under a
positive pressure of dry argon. Reagents and solvents were
handled by using standard syringe techniques. Tetrahydro-
furan, toluene, and ethyl ether were distilled from sodium and
(57) For preliminary accounts of the synthesis of enantiopure
sulfinyl dienes and enynes, see: (a) Ferna´ndez de la Pradilla, R.;
Morente, M.; Paley, R. S. Tetrahedron Lett. 1992, 33, 6101-6102. (b)
Paley, R. S.; de Dios, A.; Ferna´ndez de la Pradilla, R. Tetrahedron Lett.
1993, 34, 2429-2432. (c) Paley, R. S.; Lafontaine, J . A.; Ventura, M.
P. Tetrahedron Lett. 1993, 34, 3663-3666. (d) Paley, R. S.; Weers, H.
L.; Ferna´ndez, P.; Ferna´ndez de la Pradilla, R.; Castro, S. Tetrahedron
Lett. 1995, 36, 3605-3608.
(56) Ikeda, Y.; Yamamoto, H. Bull. Chem. Soc. J pn. 1986, 59, 657.

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6335
benzophenone; methylene chloride was distilled from CaH2.
Anhydrous dimethylformamide and anhydrous acetonitrile
were purchased from Aldrich and stored under an argon
atmosphere. All other solvents were reagent grade and were
used as purchased. Flash chromatography was performed
using Merck 230-400 silica gel 60. Analytical TLC was
carried out on Merck silica gel 60 F-254 precoated glass plates,
with detection by UV light and acidic vanillin solution or PMA
solution in ethanol. Optical rotations were measured in CHCl3
or acetone at 22 °C. Melting points are uncorrected. 1H NMR
spectra were recorded at 200, 300, 400, or 500 MHz using
CDCl3 as a solvent (unless otherwise noted). Mass spectra
were measured by direct probe injection in a low resolution
mass spectrometer using electron impact with an ionization
energy of 70 eV. Elemental analyses were obtained at the
Unidad Estructural de Ana´lisis y Te´cnicas Instrumentales del
Instituto de Qu´ımica Orga´nica of the CSIC of Madrid.
Gen er a l P r oced u r e for th e Syn th esis of (Z)-(R)-2-
Ha lovin yl p-Tolyl Su lfoxid es. To a solution of (+)-(S)-
ethynyl p-tolyl sulfoxide14 in benzene (14 mL per mmol of
sulfoxide) was added 3 equiv of zinc(II) halide, ZnX2. At the
conclusion of the reaction (as judged by TLC), the reaction
mixture was hydrolyzed with a 5% aqueous solution of sodium
bicarbonate. The aqueous phase was carefully extracted with
diethyl ether; the combined organic extracts were washed with
brine, dried (MgSO4), filtered, and concentrated in vacuo. The
residue was purified by chromatography (silica gel, hexane/
EtOAc) using the eluant indicated in each case.
(300 MHz) δ 2.40 (s, 3H), 7.01 (s, 1H), 7.26-7.35 (m, 5H), 7.45-
7.50 (m, 2H), 7.71 (d, 2H, J ) 8.1 Hz); 13C NMR (50 MHz) δ
21.4, 112.1, 124.5, 128.5, 128.7, 130.2, 130.3, 140.1, 141.0,
141.9, 144.3. Anal. Calcd for C15H13IOS: C, 48.92; H, 3.56.
Found: C, 48.67; H, 3.90.
Gen er a l P r oced u r e for Syn th esis of 1-Su lfin yl Dien es
via Stille Cou p lin g. Meth od A. To a stirred and degassed
solution of (E)-2-bromovinyl p-tolyl sulfoxide 2a 13 (1 equiv) and
the corresponding vinyltributylstannane in dry THF (6 mL/
mmol) under argon atmosphere were successively added PPh3
(0.08 equiv) and Pd2dba3‚CHCl3 (0.02 equiv), and resultant
mixture was stirred and heated to reflux over a 30 min period.
The reaction mixture was cooled, diluted with ethyl ether, and
washed with water; the aqueous phase was back-extracted
with ether, and the combined organic layers were washed with
water (three times) and then stirred with an equal volume of
a half-saturated solution of potassium fluoride for 12 h. The
precipitate of tributylstannyl fluoride was removed by filtra-
tion, and the ethereal filtrate was dried over MgSO4. Con-
centration in vacuo gave a crude product which was purified
by silica gel column chromatography using a gradient of
hexane:ethyl acetate mixtures (hexane/EtOAc, 9:1 to 3:1).
Meth od B. To a stirred and degassed solution of (E) or (Z)-
2-iodovinyl p-tolyl sulfoxide 2b,13 4b, 6a , or 6b (1 equiv) and
the corresponding vinyl tributylstannane compound in dry
DMF (6 mL/mmol) under argon atmosphere was added
Pd(CH3CN)2Cl2 (0.02 equiv), and the resulting mixture was
stirred at room temperature. The reaction was monitored by
TLC; when consumption of the starting materials was com-
plete (3 min-1 h), the solution was diluted with ethyl ether
and washed with water. The aqueous phases were back-
extracted with ether, and the combined organic layers were
washed with water and stirred with an equal volume of a half-
saturated solution of potassium fluoride for 12 h. The white
precipitate of tributylstannyl fluoride was removed by filtra-
tion, and the ethereal filtrate was dried over MgSO4. Con-
centration in vacuo gave a crude product which was purified
by silica gel column chromatography using a gradient of
hexane:ethyl acetate mixtures (hexane:EtOAc, 9:1 to 3:1).
(-)-(Z)-(R)-2-Br om oet h en yl p -Tolyl Su lfoxid e (4a ).
Yield: 75%. mp 63-64 °C (hexane); [R]D ) -473.5 (c 0.78,
1
CHCl3); H NMR (300 MHz) δ 2.42 (s, 3H), 6.86 (d, 1H, J )
6.7 Hz,), 6.99 (d, 1H, J ) 6.8 Hz), 7.34 (d, 2H, J ) 8.0 Hz).
7.62 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 21.4, 115.5,
124.1, 130.2, 140.3, 142.0, 143.2. Anal. Calcd for C9H9BrOS:
C, 44.10; H, 3.70. Found: C, 44.21; H, 3.86.
(-)-(Z)-(R)-2-Iod oet h en yl p -Tolyl Su lfoxid e (4b ).
Yield: 87%. mp 60-62 °C (hexane); [R]D ) -483.3 (c 0.45,
CHCl3); 1H NMR (300 MHz, C6D6) δ 1.93 (s, 3H), 6.13 (d, 1H,
J ) 7.3 Hz), 6.72 (d, 1H, J ) 7.2 Hz), 6.85 (d, 2H, J ) 8.2 Hz),
7.61 (d, 2H, J ) 8.2 Hz); 1H NMR (300 MHz, CDCl3) δ 2.41 (s,
3H), 7.15 (d, 1H, J ) 7.3 Hz), 7.23 (d, 1H, J ) 7.3 Hz), 7.33 (d,
2H, J ) 8.2 Hz), 7.65 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz,
CDCl3) δ 21.4, 88.9, 124.7, 130.1, 140.3, 141.9, 148.6. Anal.
Calcd for C9H9IOS: C, 37.00; H, 3.10. Found: C, 36.82; H,
3.24.
Im p r oved P r oced u r e for th e P r ep a r a tion of 4b. (+)-
(S)-Ethynyl p-tolyl sulfoxide 314 (1.948 g, 11.86 mmol) was
dissolved in anhydrous acetonitrile (25 mL) under an argon
atmosphere. To this solution were added glacial acetic acid
(1.36 mL, 23.7 mmol) and NaI (3.56 g, 23.7 mmol). After
stirring for 45 min, the mixture was diluted with EtOAc (50
mL); solid K2CO3 (4.92 g, 35.6 mmol) was added, followed by
a saturated aqueous solution of sodium thiosulfate (25 mL).
The layers were separated, and the aqueous layer was
extracted with EtOAc (2 × 35 mL). The combined organic
layers were dried (MgSO4), filtered, and concentrated in vacuo.
The residue was chromatographed (silica gel, hexane/EtOAc,
3:1) to afford 4b as a pale yellow-brown solid (3.23 g, 93%);
[R]D ) -477.4 (c 0.45, CHCl3).
(+)-(1E)-1-[(R)-p-Tolylsu lfin yl]-1,3-bu tadien e (7a). Yield
(method A): 87%. [R]D ) +283.8 (c 0.68, CHCl3); 1H NMR (200
MHz) δ 2.39 (s, 3H), 5.39 (dd, 1H, J ) 10.4, 1.1 Hz), 5.53 (dd,
1H, J ) 16.9, 1.1 Hz), 6.32 (d, 1H, J ) 15.0 Hz), 6.37 (dt, 1H,
J ) 16.9, 10.4 Hz), 6.95 (dd, 1H, J ) 15.0, 10.7 Hz), 7.28 (d,
2H, J ) 8.0 Hz), 7.49 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz)
δ 21.3, 123.7, 124.7, 130.0, 133.2, 135.9, 136.5, 140.6, 141.6.
Anal. Calcd for
C11H12OS: C, 68.71; H, 6.29; S, 16.68.
Found: C, 68.73; H, 6.37; S, 16.77.
(+)-(1E,3E)-4-P h en yl-1-[(R)-p-tolylsu lfin yl]-1,3-bu ta d i-
en e (7b). Yield (method A): 87%. mp 102 °C (Et2O/hexane);
[R]D ) +168.9 (c 0.87, CHCl3), [R]D ) +225.0 (c 0.44, acetone);
1H NMR (200 MHz) δ 2.40 (s, 3H), 6.43 (d, 1H, J ) 14.7 Hz),
6.71-6.89 (m, 2H), 7.14 (ddd, 1H, J ) 14.7, 8.1, 2.0 Hz), 7.23-
7.44 (m, 7H), 7.54 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ
21.3, 124.7, 124.8, 126.9, 128.7, 130.0, 135.7, 135.9, 136.1,
138.7, 141.0, 141.5. The physical and spectroscopic data for
this compound matched those previously described in the
literature.10b
(+)-(1E,3E)-4-n -Bu tyl-1-[(R)-p-tolylsu lfin yl]-1,3-bu ta d i-
en e (7c). Yield (method B): 75%. [R]D ) +46.5 (c 2.30,
CHCl3); 1H NMR (200 MHz) δ 0.89 (t, 3H, J ) 6.9 Hz), 1.22-
1.43 (m, 4H), 2.15 (m, 2H), 2.40 (s, 3H), 6.06-6.11 (m, 2H),
6.21 (d, 1H, J ) 14.8 Hz), 6.95 (ddd, 1H, J ) 14.9, 6.5, 3.4
Hz), 7.30 (d, 2H, J ) 8.5 Hz), 7.51 (d, 2H, J ) 8.2 Hz); 13C
NMR (50 MHz) δ 13.7, 21.3, 22.1, 30.8, 32.4, 124.6, 126.9,
129.9, 133.4, 137.3, 141.2, 141.3, 143.0. Anal. Calcd for
(-)-(Z)-(R)-2-Ch lor oet h en yl p -Tolyl Su lfoxid e (4c).
Yield: 83%. mp 77-78 °C (hexane); [R]D ) -453.9 (c 0.57,
1
CHCl3); H NMR (300 MHz) δ 2.42 (s, 3H), 6.59 (d, 1H, J )
6.7 Hz), 6.64 (d, 1H, J ) 6.7 Hz), 7.34 (d, 2H, J ) 8.0 Hz),
7.59 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ 21.4, 124.0,
126.6, 130.1, 139.9, 140.3, 142.9. Anal. Calcd for C9H9ClOS:
C, 53.86; H, 4.52. Found: C, 53.98; H, 4.71.
(-)-(Z)-(R)-2-Iod oh exen yl p -Tolyl Su lfoxid e (6a ).
Yield: 82%. [R]D ) -294.5 (c 4.30, CHCl3); 1H NMR (300 MHz)
δ 0.88 (t, 3H, J ) 7.1 Hz), 1.26 (m, 2H), 1.52 (m, 2H), 2.41 (s,
3H), 2.57 (t d, 2H, J )7.5, 1.3 Hz), 6.62 (t, 1H, J ) 1.2 Hz),
7.32 (d, 2H, J ) 7.9 Hz), 7.63 (d, 2H, J ) 8.3 Hz); 13C NMR
(50 MHz) δ 13.6, 21.2, 21.4, 30.8, 45.6, 117.7, 124.1, 130.0,
140.9, 141.6, 142.3. Anal. Calcd for C13H17IOS: C, 44.84; H,
4.92. Found: C, 44.69; H, 4.81.
C
15H20OS: C, 72.54; H, 8.12; S, 12.91. Found: C, 72.69; H,
7.90; S, 13.22.
(+)-(1E)-4-Met h yl-1-[(R)-p -t olylsu lfin yl]-1,3-p en t a d i-
en e (7d ). Yield (method A): 80%. [R]D ) +218.6 (c 1.06,
acetone); 1H NMR (200 MHz) δ 1.85 (s, 3H), 1.90 (s, 3H), 2.40
(s, 3H), 5.91 (br d, 1H, J ) 11.4 Hz), 6.19 (d, 1H, J ) 14.8 Hz),
7.22 (dd, 1H, J ) 14.8, 11.4 Hz), 7.30 (d, 2H, J ) 7.8 Hz), 7.52
(d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 18.7, 21.3, 26.3, 122.1,
124.6, 129.9, 132.8, 133.7, 141.2, 141.2, 144.5. The physical
(-)-(Z)-(R)-2-P h en yl-2-iod oet h en yl p -Tolyl Su lfoxid e
(6b). Yield: 79%. [R]D ) -138.5 (c 1.30, CHCl3); 1H NMR

6336 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
and spectroscopic data for this compound matched those
previously described in the literature.10b
(-)-(1Z)-3-Me t h yl-1-[(R )-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (10b). Yield (method B): 80%. [R]D ) -329.5 (c 0.78,
CHCl3); 1H NMR (200 MHz) δ 2.14 (br s, 3H), 2.38 (s, 3H),
5.27 (m, 2H), 6.15 (d, 1H, J ) 10.6 Hz), 6.54 (d, 1H, J ) 10.6
Hz), 7.29 (d, 2H, J ) 8.0 Hz), 7.50 (d, 2H, J ) 8.1 Hz); 13C
NMR (50 MHz) δ 21.3, 22.8, 124.0, 124.3, 130.0, 130.2, 135.9,
139.7, 139.8, 141.2. Anal. Calcd for C12H14OS: C, 69.86; H,
6.84; S, 15.54. Found: C, 69.92; H, 6.88; S, 15.33.
(+)-(1E )-3-Me t h yl-1-[(R )-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (7e). Yield (method B): 83%. [R]D ) +207.6 (c 0.66,
CHCl3); 1H NMR (200 MHz) δ 1.80 (br s, 3H), 2.38 (s, 3H),
5.27 (m, 2H), 6.25 (d, 1H, J ) 15.3 Hz), 7.03 (d, 1H, J ) 15.3
Hz), 7.28 (d, 2H, J ) 8.1 Hz), 7.50 (d, 2H, J ) 8.2 Hz); 13C
NMR (50 MHz) δ 18.3, 21.4, 122.9, 124.7, 130.0, 133.5, 138.9,
139.3, 140.8, 141.6. Anal. Calcd for C12H14OS: C, 69.86; H,
6.84; S, 15.54. Found: C, 70.03; H, 6.91; S, 15.39.
(+)-(1E )-3-E t h oxy-1-[(R )-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (7f). Yield (method B): 90%. [R]D ) +382.8 (c 0.87,
CHCl3); 1H NMR (200 MHz) δ 1.26 (t, 3H, J ) 7.0 Hz), 2.38 (s,
3H), 3.76 (q, 2H, J ) 7.0 Hz), 4.35 (d, 1H, J ) 2.1 Hz), 4.39 (d,
1H, J ) 2.1 Hz), 6.62 (d, 1H, J ) 14.8 Hz), 6.76 (d, 1H, J )
14.8 Hz), 7.29 (d, 2H, J ) 8.3 Hz), 7.51 (d, 2H, J ) 8.2 Hz);
13C NMR (50 MHz) δ 14.2, 21.3, 63.1, 92.0, 124.9, 130.0, 131.5,
133.3, 140.4, 141.7, 155.9. Anal. Calcd for C13H16O2S: C,
66.07; H, 6.82; S, 13.57. Found: C, 65.78; H, 7.05; S, 13.81.
(+)-(1E,3E)-5,5-Dieth oxy-1-[(R)-p-tolylsu lfin yl]-1,3-p en -
ta d ien e (7g). Yield (method A): 85%. [R]D ) +142.9 (c 1.05,
CHCl3); 1H NMR (200 MHz) δ 1.18 (t, 6H, J ) 7.1 Hz), 2.37 (s,
3H), 3.39-3.65 (m, 4H), 4.96 (d, 1H, J ) 4.5 Hz), 5.96 (dd,
1H, J ) 15.3, 4.5 Hz), 6.36 (d, 1H, J ) 14.8), 6.39 (dd, 1H, J
) 15.3, 10.8 Hz), 6.95 (dd, 1H, J ) 14.9, 10.8 Hz), 7.27 (d, 2H,
J ) 8.1 Hz), 7.47 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ
15.2, 21.4, 61.1, 99.9, 124.8, 129.0, 130.1, 134.4, 136.7, 137.3,
140.4, 141.8. Anal. Calcd for C16H22O3S: C, 65.27; H, 7.53;
S, 10.89. Found: C, 64.84; H, 7.86; S, 10.63.
(+)-(1E,3E)-5,5-Dieth oxy-4-m eth yl-1-[(R)-p-tolylsu lfin yl]-
1,3-p en ta d ien e (7h ). Yield (method A): 61%. [R]D ) +200.7
(c 1.18, CHCl3); 1H NMR (400 MHz) δ 1.22 (t, 6H, J ) 7.0 Hz),
1.90 (d, 3H, J ) 0.9 Hz), 2.41 (s, 3H3), 3.44 (m, 2H), 3.59 (m,
2H), 4.73 (s, 1H), 6.29 (d, 1H, J ) 11.3 Hz), 6.37 (d, 1H, J )
14.8 Hz), 7.26 (dd, 1H, J ) 14.8, 11.4 Hz), 7.31 (d, 2H, J ) 8.0
Hz), 7.52 (d, 2H, J ) 8.0 Hz); 13C NMR (100 MHz) δ 12.9, 15.1,
21.4, 61.67, 61.70, 103.8, 123.4, 124.8, 130.1, 131.4, 136.7,
140.7, 141.6, 142.5. Anal. Calcd for C17H24O3S: C, 66.20; H,
7.84. Found: C, 66.37; H, 7.99.
(-)-(1Z)-4-Met h yl-1-[(R)-p -t olylsu lfin yl]-1,3-p en t a d i-
en e (10c). Yield (method B): 91%. [R]D ) -503.7 (c 1.08,
1
CHCl3); H NMR (200 MHz) δ 1.85 (s, 3H), 1.94 (s, 3H), 2.40
(s, 3H), 6.02 (d, 1H, J ) 9.4 Hz), 6.68 (br d, 1H, J ) 11.6 Hz),
6.86 (dd, 1H, J ) 11.6, 9.5 Hz), 7.30 (d, 2H, J ) 8.0 Hz), 7.51
(d, 1H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 18.5, 21.3, 26.6, 119.2,
123.9, 129.8, 132.5, 134.1, 140.8, 141.4, 145.4. Anal. Calcd for
C13H16OS: C, 70.86; H, 7.32; S, 14.55. Found: C, 70.58; H,
7.60; S, 14.31.
(-)-(1Z)-3-E t h oxy-1-[(R )-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (10d ). Yield (method B): 83%. [R]D ) -623.8 (c 0.21,
CHCl3); 1H NMR (200 MHz) δ 1.38 (t, 3H, J ) 7.0 Hz), 2.39 (s,
3H), 3.89 (q, 2H, J ) 7.0 Hz), 4.37 (d, 1H, J ) 2.3 Hz), 4.41 (d,
1H, J ) 2.3 Hz), 6.03 (d, 1H, J ) 10.7 Hz), 6.20 (d, 1H, J )
10.7 Hz), 7.26 (d, 2H, J ) 8.0 Hz), 7.55 (d, 2H, J ) 8.2 Hz);
13C NMR (50 MHz) δ 14.5, 21.3, 63.9, 92.8, 124.3, 129.8, 130.9,
138.7, 140.6, 142.5, 156.5. Anal. Calcd for C13H16O2S: C,
66.07; H, 6.82; S, 13.57. Found: C, 66.34; H, 7.05; S, 13.29.
(-)-(1Z,3E)-5,5-Dieth oxy-1-[(R)-p-tolylsu lfin yl]-1,3-p en -
ta d ien e (10e). Yield (method B): 76%. [R]D ) -244.0 (c 0.25,
CHCl3); 1H NMR (400 MHz) δ 1.21 (t, 6H, J ) 7.0 Hz), 2.41 (s,
3H), 3.51-3.74 (m, 4H), 5.05 (d, 1H, J ) 4.7 Hz), 5.99 (dd,
1H, J ) 15.3, 4.7 Hz), 6.21 (d, 1H, J ) 9.7 Hz), 6.62 (app t,
1H, J ) 11.1 Hz), 7.19 (dd, 1H, J ) 15.3, 11.2 Hz), 7.31 (d,
2H, J ) 8.1 Hz), 7.50 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz)
δ 15.2, 21.3, 61.4, 61.5, 100.1, 124.1, 126.3, 130.1, 136.5, 137.1,
138.2, 140.7, 141.3. Anal. Calcd for C16H22O3S: C, 65.27; H,
7.53. Found: C, 64.91; H, 7.93.
(-)-(1Z,3E)-5,5-Dieth oxy-4-m eth yl-1-[(R)-p-tolylsu lfin yl]-
1,3-p en ta d ien e (10f). Yield (method B): 75%. [R]D ) -330.6
(c 2.26, CHCl3); 1H NMR (400 MHz) δ 1.14 (overlapping
triplets, 6H), 1.74 (s, 3H), 2.28 (s, 3H), 3.39 (m, 2H), 3.52 (m,
2H), 4.68 (s, 1H), 6.08 (d, 1H, J ) 9.6 Hz), 6.77 (dd, 1H, J )
11.8, 9.6 Hz), 6.93 (d, 1H, J ) 11.8 Hz), 7.18 (d, 2H, J ) 7.9
Hz), 7.39 (d, 2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ 13.2, 16.0,
22.2, 62.87, 62.90, 105.1, 121.3, 124.9, 130.8, 133.5, 137.4,
141.86, 141.94, 144.6. Anal. Calcd for C17H24O3S: C, 66.20;
H, 7.84. Found: C, 66.02; H, 8.01.
(-)-(1Z,3E)-3-Bu tyl-1-[(R)-p-tolylsu lfin yl]-1,3-pen tadien -
5-ol (10g). Yield (method B): 77%. [R]D ) -17.9 (c 0.74,
CHCl3); 1H NMR (400 MHz) δ 0.91 (t, 3H, J ) 7.1 Hz), 1.23-
1.50 (m, 4H), 2.28 (t, 2H, J ) 7.5 Hz), 2.39 (s, 3H), 3.40 (br s,
1H), 4.30 (d, 2H, J ) 5.1 Hz), 5.88 (t, 1H, J ) 5.9 Hz), 6.20 (d,
1H, J ) 10.3 Hz), 6.52 (d, 1H, J ) 10.3 Hz), 7.29 (d, 2H, J )
7.8 Hz), 7.54 (d, 2H, J ) 8.0 Hz); 13C NMR (100 MHz) δ 13.7,
21.2, 22.4, 29.7, 30.6, 58.7, 124.5, 129.9, 135.7, 136.4, 136.6,
141.18, 141.23, 141.5. Anal. Calcd for C16H22O2S: C, 69.03;
H, 7.96. Found: C, 68.87; H, 8.13.
(-)-(1Z,3E )-5-[(t er t -Bu t yld im e t h ylsilyl)oxy]-3-(h y-
dr oxym eth yl)-1-[(R)-p-tolylsu lfin yl]-1,3-pen tadien e (10h ).
Yield: 87% (using method B, except the residue was n ot
treated with aqueous KF solution). Purification of the crude
product was accomplished with two successive gradient chro-
matographies (silica gel; hexane/EtOAc, 9:1 to 1:2); analytically
pure 10h was obtained by recrystallization from toluene (mp
104-106 °C). [R]D ) -230.4 (c 1.12, CHCl3); 1H NMR (400
MHz) δ 0.06 (s, 6H), 0.88 (s, 9H), 2.35 (s, 3H), 3.87 (app t, 1H,
J ) 5.4 Hz), 4.35-4.40 (m, 4H), 5.88 (app t, 1H, J ) 5.7 Hz),
6.15 (d, 1H, J ) 10.5 Hz), 6.55 (d, 1H, J ) 10.5 Hz), 7.23 (d,
2H, J ) 8.1 Hz), 7.54 (d, 2H, J ) 8.1 Hz); 13C NMR (100
MHz) δ -5.40, -5.38, 18.1, 21.2, 25.71, 25.72, 58.8, 59.6, 124.5,
129.8, 135.5, 135.6, 138.8, 139.1, 141.1. Anal. Calcd for
C19H30O3SSi: C, 62.25; H, 8.25. Found: C, 62.45; H, 8.51.
(-)-(1Z,3E)-3-(Hyd r oxym eth yl)-1-[(R)-p-tolylsu lfin yl]-
5-[(tr iisopr opylsilyl)oxy]-1,3-pen tadien e (10i). Yield: 89%
(method B, except the residue was n ot treated with aqueous
KF solution). Purification of the crude product was ac-
complished with two successive gradient chromatographies
(+)-(1E,3E)-8-(1,3-Dith iola n -2-yl)-1-[(R)-p-tolylsu lfin yl]-
1,3-octa d ien e (7i). Yield (method A): 83%. [R]D ) +78.3 (c
0.97, CHCl3); 1H NMR (200 MHz) δ 1.53 (m, 2H, J ) 7.0 Hz),
1.78 (m, 2H), 2.15 (m, 2H), 2.36 (s, 3H), 3.18 (m, 4H), 4.42 (t,
1H, J ) 6.9 Hz), 5.92-6.10 (m, 2H), 6.19 (d, 1H, J ) 15.0 Hz),
6.90 (dd, 1H, J ) 15.0, 8.8 Hz), 7.27 (d, 2H, J ) 8.0 Hz), 7.48
(d, 2H, J ) 8.0 Hz); 13C NMR (50 MHz) δ 21.3, 28.1, 32.3, 38.4,
38.7, 53.4, 124.7, 127.4, 130.0, 133.9, 136.8, 141.2, 141.4, 141.7.
Anal. Calcd for C17H22OS3: C, 60.31; H, 6.55. Found: C,
60.57; H, 6.73.
(+)-(1E,3E,5E)-1,6-Bis[(R)-p -t olylsu lfin yl]-1,3,5-h exa -
tr ien e (8). Yield (method B): 68%. mp 131 °C (Et2O/petrol-
1
eum ether, -18 °C); [R]D ) +756.4 (c 0.39, CHCl3); H NMR
(300 MHz) δ 2.38 (s, 6H), 6.45 (d, 2H, J ) 14.8 Hz), 6.49 (m,
2H), 6.99 (ddd, 2H, J ) 14.8, 7.4, 3.1 Hz), 7.29 (d, 4H, J )
8.0 Hz), 7.48 (d, 4H, J ) 8.2 Hz); 13C NMR (75 MHz) δ 21.4,
124.9, 130.2, 133.5, 133.6, 138.7, 140.1, 142.1. Anal. Calcd
for C20H20O2S2: C, 67.38; H, 5.65; S, 17.99. Found: C, 67.67;
H, 5.40; S, 17.73.
(+)-(1E)-1-[(R)-p-Tolylsu lfin yl]-1,4-pen tadien e (9). Yield
(method A): 71%. [R]D ) +132.4 (c 1.14, CHCl3); 1H (200 MHz)
NMR δ 2.41 (s, 3H), 2.97 (tq, 2H, J ) 6.3, 1.4 Hz), 5.10 (m,
2H), 5.79 (m, 1H), 6.24 (dt, 1H, J ) 15.2, 1.5 Hz), 6.62 (dt,
1H, J ) 15.2, 6.3 Hz), 7.31 (d, 2H, J ) 8.3 Hz), 7.52 (d, 2H, J
) 8.2 Hz); 13C NMR (50 MHz) δ 21.3, 35.7, 117.4, 124.5, 129.9,
133.6, 136.1, 137.5, 141.0, 141.3. Anal. Calcd for C12H14OS:
C, 60.31; H, 6.55. Found: C, 60.17; H, 6.73.
(-)-(1Z)-1-[(R)-p-Tolylsu lfin yl]-1,3-bu tadien e (10a). Yield
(method B): 91%. [R]D ) -438.5 (c 0.52, CHCl3); 1H NMR (200
MHz) δ 2.40 (s, 3H), 5.52 (dd, 1H, J ) 9.9, 0.4 Hz), 5.55 (dd,
1H, J ) 16.5, 0.4 Hz), 6.17 (d, 1H, J ) 9.8 Hz), 6.60 (app t,
1H, J ) 9.8 Hz), 7.18 (dt, 1H, J ) 16.6, 9.8 Hz), 7.31 (d, 2H,
J ) 8.0 Hz), 7.50 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ
21.2, 123.9, 125.0, 129.9, 130.5, 136.4, 137.8, 140.9, 141.1.
Anal. Calcd for C11H12OS: C, 68.71; H, 6.29; S, 16.68.
Found: C, 68.81; H, 6.50; S, 16.39.

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6337
(silica gel; hexane/EtOAc, 19:1 to 1:1). [R]D ) -211.1 (c 3.03,
CHCl3); 1H NMR (400 MHz) δ 1.06-1.18 (m, 21H), 2.40 (s,
3H), 3.41 (br, 1H), 4.45 (m, 4H), 5.97 (app t, 1H, J ) 5.7 Hz),
6.22 (d, 2H, J ) 10.5 Hz), 6.62 (d, 2H, J ) 10.5 Hz), 7.29 (d,
2H, J ) 8.2 Hz), 7.59 (d, 2H, J ) 8.2 Hz); 13C (100 MHz) NMR
δ 12.7, 18.8, 22.2, 60.1, 60.9, 125.4, 130.9, 136.6, 136.7, 139.7,
140.3, 142.1, 142.2. Anal. Calcd for C22H36O3SSi: C, 64.66;
H, 8.88. Found: C, 64.91; H, 8.67.
(-)-(1Z)-2-n -Bu t yl-1-[(R)-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (10j). Yield (method B): 80%. [R]D ) -310.1 (c 1.23,
CHCl3); 1H NMR (400 MHz) δ 0.87 (t, 3H, J ) 7.0 Hz), 1.22-
1.54 (m, 4H), 2.31 (app t, 2H, J ) 7.3 Hz), 2.40 (s, 3H), 5.48
(dd, 1H, J ) 11.0, 0.8 Hz), 5.60 (dd, 1H, J ) 17.3, 0.8 Hz),
6.09 (s, 1H), 7.22 (ddd, 1H, J ) 17.3, 11.0, 0.7 Hz), 7.30 (d,
2H, J ) 8.0 Hz), 7.48 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz)
δ 13.6, 21.2, 22.3, 30.1, 32.3, 119.9, 124.0, 129.8, 131.6, 134.5,
140.8, 141.5, 148.6. Anal. Calcd for C15H20OS: C, 72.54; H,
8.12; S, 12.91. Found: C, 72.71; H, 8.00; S, 12.77.
(+)-1(S)-(p-Tolylsu lfin yl)-4-[(4-m eth oxyben zyl)oxy]-1-
1
bu tyn e (12). Yield: 38%. [R]D ) +22.9 (c 1.57, CHCl3); H
NMR (400 MHz) δ 2.72 (t, 2H, J ) 6.8 Hz), 3.60 (t, 2H, J )
6.8 Hz), 3.81 (s, 3H), 4.46 (s, 2H), 6.87 (d, 2H, J ) 8.4 Hz),
7.23 (d, 2H, J ) 8.4 Hz), 7.33 (d, 2H, J ) 8.2 Hz), 7.69 (d, 2H,
J ) 8.1 Hz); 13C NMR (100 MHz) δ 22.1, 22.3, 56.1, 67.5, 73.6,
79.9, 103.3, 114.7, 126.0, 130.2, 130.5, 131.0, 141.8, 143.8,
160.1. Anal. Calcd for C19H20O3S: C, 69.48; H, 6.14. Found:
C, 69.67; H, 6.29.
(+)-1(S)-(p -Tolylsu lfin yl)-2-(t r iet h ylsilyl)et h yn e (13).
Yield: 67%. [R]D ) +54.5 (c 1.35, CHCl3); 1H NMR (400 MHz)
δ 0.67 (q, 6H, J ) 8.0 Hz), 0.98 (t, 9H, J ) 8.0 Hz), 2.44 (s,
3H), 7.35 (d, 2H, J ) 8.0 Hz), 7.72 (d, 2H, J ) 8.2 Hz); 13C
NMR (100 MHz) δ 4.6, 8.1, 22.3, 102.2, 109.7, 126.0. Anal.
Calcd for C15H22OSSi: C, 64.69; H, 7.96. Found: C, 64.85; H,
8.10.
(+)-1(S)-(p-Tolylsu lfin yl)-4-[(4-m eth oxyben zyl)oxy]-1-
1
h exyn e (25). Yield: 57%. [R]D ) +35.9 (c 2.26, CHCl3); H
NMR (200 MHz) δ 1.62-1.68 (m, 4H), 2.40 (s, 3H), 2.42 (m,
2H), 3.41 (m, 2H), 3.78 (s, 3H), 4.38 (s, 2H), 6.85 (d, 2H, J )
8.7 Hz); 7.22 (d, 2H, J ) 8.9 Hz), 7.31 (d, 2H, J ) 8.1 Hz),
7.66 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ 19.5, 21.4, 24.4,
28.7, 55.2, 69.0, 72.5, 78.5, 105.4, 113.8, 125.1, 129.1, 130.1,
130.5, 141.3, 142.2, 159.2. Anal. Calcd for C21H24O3S: C,
70.75; H, 6.79. Found: C, 70.48; H, 6.98.
(-)-(1Z,3E)-1-[(R)-p-Tolylsu lfin yl]-2-n -bu tyl-4-p h en yl-
1,3-bu ta d ien e (10k ). Yield (Mmthod B): 92%. [R]D ) -663.2
(c 0.98, CHCl3); 1H NMR (200 MHz) δ 0.91 (t, 3H, J ) 7.2 Hz),
1.26-1.58 (m, 4H), 2.39 (s, 3H), 2.45 (m, 2H), 6.14 (br s, 1H),
6.91 (d, 1H, J ) 16.1 Hz), 7.27-7.43 (m, 5H), 7.49-7.55 (m,
4H), 7.67 (d, 1H, J ) 16.1 Hz); 13C NMR (50 MHz) δ 13.7, 21.2,
22.4, 30.4, 32.9, 123.0, 124.0, 127.0, 128.7, 129.8, 134.1, 134.3,
136.1, 140.7, 141.5, 148.7. Anal. Calcd for C21H24OS: C, 77.73;
H, 7.45. Found: C, 77.63; H, 7.69.
Gen er a l P r oced u r e for th e P r ep a r a tion of (1E)-2-
Su bstitu ted -1-su lfin yl Dien es via Vin ylcu p r a tion . To a
suspension of CuI (4.2 equiv) in THF (10 mL/mmol sulfoxide)
at -20 °C was added a 1.0 M THF solution of vinylmagnesium
bromide (Aldrich, 4 equiv); this solution was stirred at -20
°C for 20 min. A THF (5 mL/mmol sulfoxide) solution of the
corresponding alkynyl sulfoxide (1 equiv) was then added
dropwise via syringe. After 5 min the reaction was quenched
with a 9:1 aqueous solution of saturated NH4Cl/NH4OH and
diluted with EtOAc. (For 14b, a THF (5 mL/mmol sulfoxide)
solution of NIS (2 equiv) was added via syringe and stirred
for 10 min prior to aqueous workup. After quenching and
diluting the reaction as described, the organic layer was
washed with saturated aqueous Na2S2O3). The layers were
separated, and the aqueous layer was extracted with EtOAc;
the combined organic layers were washed with brine, dried
(MgSO4), and concentrated in vacuo. Chromatography (silica
gel, hexane/EtOAc mixtures) afforded the desired 1-sulfinyl
diene.
(-)-(1Z,3E)-2-Bu tyl-5-[(ter t-bu tyld im eth ylsilyl)oxy]-3-
(h yd r oxym et h yl)-1-[(R)-p -t olylsu lfin yl]-1,3-p en t a d ien e
(10l). Yield: 68% (method B, except the residue was n ot
treated with aqueous KF solution). Purification of the crude
product was accomplished with two successive gradient chro-
matographies (silica gel; hexane/EtOAc, 19:1 to 1:1). mp 44-
1
46.5 °C; [R]D ) -9.25 (c 0.98, CHCl3); H NMR (400 MHz) δ
0.11 (s, 6H), 0.86 (t, 3H, J ) 7.1 Hz), 0.91 (s, 9H), 1.26-1.43
(m, 4H), 2.28 (t, 2H, J ) 7.8 Hz), 2.40 (s, 3H), 3.49 (t, 1H, J )
6.4 Hz), 4.27 (ABX system, 2H, J ) 13.1, 6.6, 5.8 Hz), 4.40 (m,
2H), 5.73 (app t, 1H, J ) 5.8 Hz), 6.14 (d, 1H, J ) 0.9 Hz),
7.29 (d, 2H, J ) 8.2 Hz), 7.54 (d, 2H, J ) 8.2 Hz); 13C NMR
(100 MHz) δ -5.30, -5.27, 13.8, 18.2, 21.3, 22.1, 25.8, 29.3,
36.0, 59.2, 59.4, 124.5, 129.9, 132.6, 133.5, 138.8, 141.0, 141.5,
156.7. Anal. Calcd for C23H38O3SSi: C, 65.35; H, 9.06.
Found: C, 65.16; H, 8.82.
(-)-(1Z)-2-P h e n yl-1-[(R )-p -t olylsu lfin yl]-1,3-b u t a d i-
en e (10m ). Yield (method B): 89%. [R]D ) -92.8 (c 1.30,
(-)-(1E)-1-[(R)-p -Tolylsu lfin yl]-2-b u t yl-1,3-b u t a d ien e
1
(14a ). Yield: 93%. [R]D ) -258.1 (c 1.79, CHCl3); H NMR
1
CHCl3); H NMR (300 MHz) δ 2.41 (s, 3H), 5.41 (d, 1H, J )
(400 MHz) δ 0.96 (t, 3H, J ) 7.1 Hz), 1.45 (m, 2H), 1.61 (m,
2H), 2.40 (s, 3H), 2.70 (m, 2H), 5.35 (d, 1H, J ) 10.8 Hz), 5.56
(d, 1H, J ) 17.4 Hz), 6.16 (s, 1H), 6.23 (dd, 1H, J ) 17.4, 10.8
Hz), 7.31 (d, 2H, J ) 7.8 Hz), 7.51 (d, 2H, J ) 8.0 Hz); 13C
NMR (100 MHz) δ 14.7, 22.2, 23.7, 28.9, 32.8, 120.3, 125.1,
130.9, 136.4, 137.4, 142.0, 142.3, 150.7. Anal. Calcd for
C15H20OS: C, 72.53; H, 8.11. Found: C, 72.38; H, 8.02.
(-)-(1Z)-1-Iod o-1-[(S)-p-tolylsu lfin yl]-2-bu tyl-1,3-bu ta -
d ien e (14b). Yield: 65%. mp 179-180 °C; [R]D ) -123.6 (c
17.2 Hz), 5.66 (d, 1H, J ) 10.7 Hz), 6.27 (s, 1H), 7.24-7.45
(m, 8H), 7.56 (d, 2H, J ) 8.2 Hz); 13C NMR (75 MHz) δ 21.3,
124.2, 124.6, 128.3, 128.5, 128.9, 130.0, 132.0, 135.5, 137.4,
141.1, 141.5, 149.2. Anal. Calcd for C17H16OS: C, 76.08; H,
6.01. Found: C, 76.23; H, 5.87.
(-)-(1Z,3E,5Z)-1,6-Bis[(R)-p -t olylsu lfin yl]-1,3,5-h exa -
tr ien e (11). Yield (method B): 83%. [R]D ) -490.0 (c 0.50,
1
CHCl3); H NMR (200 MHz) δ 2.38 (s, 6H), 6.27 (d, 2H, J )
1
9.7 Hz), 6.71 (app td, 2H, J ) 10.5, 3.1 Hz), 7.28-7.34
(m, 6H), 7.48 (d, 4H, J ) 8.0 Hz); 13C NMR (50 MHz) δ 21.4,
124.2, 130.2, 132.2, 135.9, 138.8, 140.6, 141.7. Anal. Calcd
for C20H20O2S2: C, 67.38; H, 5.65; S, 17.99. Found: C, 67.51;
H, 5.59; S, 17.68.
1.27, CHCl3); H NMR (400 MHz) δ 0.97 (t, 3H, J ) 7.2 Hz),
1.45 (sextet, 2H, J ) 7.0 Hz), 1.60 (m, 2H), 2.39 (s, 3H), 3.01
(m, 2H), 5.53 (d, 1H, J ) 11.0 Hz), 5.70 (d, 1H, 17.3 Hz), 6.67
(dd, 1H, J ) 17.3, 11.0 Hz), 7.29 (d, 2H, J ) 8.0 Hz), 7.44 (d,
2H, J ) 8.3 Hz); 13C NMR (100 MHz) δ 14.6, 22.3, 23.6, 32.8,
33.2, 121.4, 123.6, 125.5, 130.6, 141.4, 141.6, 142.3, 153.3.
Anal. Calcd for C15H19IOS: C, 48.14; H, 5.12. Found: C,
48.01; H, 5.23.
Gen er a l P r oced u r e for th e P r ep a r a tion of 1-Su lfin yl
Alk yn es. To the corresponding alkyne (1.12 equiv) at 0 °C
was added a 3.0 M Et2O solution of ethylmagnesium bromide
(Aldrich, 1 equiv) via syringe. After 5 min, the ice bath was
removed and the mixture was heated at 40 °C for 20 min. After
cooling the mixture to -20 °C, a toluene (1.8 mL/mmol
sulfinate ester) solution of (-)-menthyl (S)-p-toluenesulfinate
(579 mg, 1.34 equiv), precooled to 0 °C, was added quickly via
cannula. The mixture was stirred at -20 °C for 30 min and
then allowed to warm to 0 °C over 30 min. The reaction was
quenched with saturated aqueous NH4Cl; the layers were
separated, and the aqueous layer was extracted with EtOAc.
The combined organic layers were dried (MgSO4), filtered, and
concentrated in vacuo to afford a residue which was chromato-
graphed (silica gel, hexane/EtOAc mixtures) to afford the
desired 1-sulfinyl alkyne.
(-)-(1E)-1-[(R)-p -Tolylsu lfin yl]-2-[2-[(4-m et h oxyb en z-
yl)oxy]eth yl]-1,3-bu ta d ien e (14c). Yield: 80%. [R]D
)
1
-135.6 (c 1.66, CHCl3); H NMR (400 MHz) δ 2.92 (m, 1H),
3.19 (m, 1H), 3.56 (m, 1H), 3.66 (m, 1H), 3.81 (s, 3H), 4.47
(AB quartet, 2H, J ) 11.5 Hz), 5.35 (d, 1H, J ) 10.8 Hz), 5.56
(d, 1H, J ) 17.5 Hz), 6.24 (dd, 1H, J ) 17.4, 10.7 Hz), 6.25 (s,
1H), 6.88 (d, 2H, J ) 8.3 Hz), 7.20 (d, 2H, J ) 7.9 Hz), 7.26 (d,
2H, J ) 9.1 Hz), 7.48 (d, 2H, J ) 8.0 Hz); 13C NMR (100 MHz)
δ 22.2, 29.8, 30.5, 56.1, 69.1, 73.5, 114.6, 120.5, 125.3, 130.3,
130.7, 130.9, 137.3, 138.4, 141.8, 146.5, 160.1. Anal. Calcd
for C21H24O3S: C, 70.75; H, 6.79. Found: C, 70.65; H, 6.87.
(-)-(1E)-1-[(R)-p-Tolylsu lfin yl]-2-(tr ieth ylsilyl)-1,3-bu ta-
1
d ien e (14d ). Yield: 47%. [R]D ) -66.5 (c 1.62, CHCl3); H

6338 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
NMR (400 MHz) δ 0.90 (q, 6H, J ) 7.3 Hz), 1.01 (t, 9H, J )
7.6 Hz), 2.42 (s, 3H), 5.04 (d, 1H, J ) 10.5 Hz), 5.24 (d, 1H, J
) 16.8 Hz), 6.43 (dd, 1H, J ) 16.8, 10.5 Hz), 6.84 (s, 1H), 7.32
(d, 2H, J ) 8.0 Hz), 7.51 (d, 2H, J ) 8.1 Hz); 13C NMR (100
MHz) δ 5.5, 8.2, 22.2, 117.5, 125.3, 130.9, 140.6, 141.9, 142.1,
146.3, 153.8. Anal. Calcd for C17H26OSSi: C, 66.61; H, 8.55.
Found: C, 66.69; H, 8.72.
Gen er a l P r oced u r e for th e P r ep a r a tion of (E)-1-Su lfi-
n yl-1-en -3-yn es. To a benzene or toluene solution of (E)-2-
bromovinyl-p-tolyl sulfoxide 2a 13 (0.05 to 0.10 M) were added
the appropriate alkyne (1.2 equiv), DBU (2 equiv), and CuI
(0.3 equiv). After deaerating the solution for 5 min (by
bubbling argon into the solution), Pd(PPh3)4 (0.05 equiv) was
added. The brown reaction mixture was stirred at room
temperature for 40 min. It was then diluted with EtOAc,
washed with two portions of a saturated aqueous NH4Cl
solution, dried (MgSO4), filtered, and concentrated in vacuo.
The crude product was purified by chromatography (silica gel,
hexane/EtOAc mixtures).
(+)-(1E)-1-[(R)-p-Tolylsu lfin yl]pen t-1-en -3-yn -5-ol (15a).
Yield: 84%. [R]D ) +256.9 (c 0.47, CHCl3); 1H NMR (400 MHz)
δ 2.40 (s, 3H), 3.62 (br t, 1H, J ) 6.1 Hz), 4.36 (br d, 2H, J )
5.1 Hz), 6.54 (dd, 1H, J ) 15.2, 1.5 Hz), 6.68 (d, 1H, J ) 15.2
Hz), 7.30 (d, 2H, J ) 8.1 Hz), 7.48 (d, 2H, J ) 8.1 Hz); 13C
NMR (100 MHz) δ 21.4, 51.0, 80.3, 96.0, 115.5, 125.1, 130.3,
138.8, 142.5, 144.2. Anal. Calcd for C12H12O2S: C, 65.43; H,
5.49. Found: C, 65.31; H, 5.23.
130.6, 138.6, 140.1, 141.8, 170.6. Anal. Calcd for C13H14O3S:
C, 62.38; H, 5.64. Found: C, 62.41; H, 5.43.
(+)-(1E,3Z)-1-[(R)-p-Tolylsu lfin yl]-1,3-octa d ien e (16b).
To a benzene (2 mL) solution of sulfinyl enyne 15b (20.6 mg,
0.084 mmol) was added RhCl(PPh3)3 (2 mg, 10 wt %). The
flask was placed under a hydrogen atmosphere (1 atm) and
stirred at room temperature for 14 h. The solution was filtered
through Celite to remove the catalyst and concentrated in
vacuo; the crude material was chromatographed (silica gel,
hexane/EtOAc, 9:1) to afford 16b (17.5 mg, 84%) as a colorless
1
oil. [R]D ) +257.9 (c 1.24, CHCl3), H NMR (400 MHz) δ 0.93
(t, 3H, J ) 7.2 Hz), 1.38 (m, 4H), 2.30 (m, 2H), 2.41 (s, 3H),
5.78 (m, 1H), 6.06 (t, 1H, J ) 11.2 Hz), 6.29 (d, 1H, J ) 14.7
Hz), 7.29 (partially obscured m, 1H), 7.30 (d, 2H, J ) 8.1 Hz),
7.52 (d, 2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ 13.9, 21.4,
22.3, 27.8, 31.4, 124.7, 125.0, 130.0, 131.7, 135.4, 139.9, 140.9,
141.5. Anal. Calcd for C15H20OS: C, 72.53; H, 8.12. Found:
C, 72.38; H, 7.98.
Gen er a l P r oced u r e for th e P r ep a r a tion of (Z)-1-Su lfi-
n yl-1-en -3-yn es. To a stirred and degassed solution of
(Z)-2-iodovinyl p-tolyl sulfoxide 4b (1 equiv) and the corre-
sponding alkynyl tributylstannane (1.3 equiv) compound in dry
DMF (6 mL/mmol) under argon atmosphere, was added
Pd(CH3CN)2Cl2 (0.02 equiv) and the resulting mixture was
stirred at room temperature. The reaction was monitored by
TLC; when consumption of the starting materials was com-
plete (3 min-1 h), the solution was diluted with ethyl ether
and washed with water. The aqueous phases were back-
extracted with ether, and the combined organic layers were
washed with water and stirred with an equal volume of a half-
saturated solution of potassium fluoride for 12 h (except for
17c and 17d ). The white precipitate of tributylstannyl fluoride
was removed by filtration, and the ethereal filtrate was dried
over MgSO4. Concentration in vacuo gave a crude product
which was purified by silica gel column chromatography using
a gradient of hexane:ethyl acetate mixtures (hexane/EtOAc,
9:1 to 3:1). Purification of 17c and 17d required two successive
gradient chromatographies instead of KF treatment followed
by a single chromatography.
(+)-(1E)-1-[(R)-p -Tolylsu lfin yl]oct -1-en -3-yn e
(15b ).
Yield: 84%. [R]D ) +190.4 (c 1.04, CHCl3); 1H NMR (400 MHz)
δ 0.89 (t, 3H, J ) 7.3 Hz), 1.36 (m, 2H), 1.51 (m, 2H), 2.32 (dt,
2H, J ) 7.0, 2.1 Hz), 2.39 (s, 3H), 6.45 (dt, 1H, J ) 15.2, 2.2
Hz), 6.60 (d, 1H, J ) 15.2 Hz), 7.30 (d, 2H, J ) 8.2 Hz), 7.49
(d, 2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ 13.4, 19.2, 21.3,
21.8, 30.2, 76.1, 98.9, 116.9, 124.8, 130.1, 139.9, 141.9, 143.4.
Anal. Calcd for C15H18OS: C, 73.13; H, 7.36. Found: C, 73.31;
H, 7.51.
(+)-(1E)-1-[(R)-p-Tolylsu lfin yl]-7-[(ter t-bu tyld im eth yl-
silyl)oxy]h ep t-1-en -3-yn e (15c). Yield: 86%. [R]D ) +155.0
(c 0.20, CHCl3); 1H NMR (400 MHz) δ 0.04 (s, 6H), 0.88 (s,
9H), 1.72 (quint, 2H), 2.41 (s, 3H), 2.43 (partially obscured dt,
2H, J ) 7.1, 2.2 Hz), 3.67 (t, 2H, J ) 5.9 Hz), 6.46 (dt, 1H, J
) 15.3, 2.2 Hz), 6.60 (d, 1H, J ) 15.3 Hz), 7.30 (d, 2H, J ) 8.2
Hz), 7.50 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz) δ -5.4,
16.0, 18.2, 21.4, 25.8, 31.2, 61.3, 76.2, 98.5, 116.8, 124.9, 130.1,
139.9, 141.9, 143.5. Anal. Calcd for C20H30O2SSi: C, 66.25;
H, 8.34. Found: C, 66.47; H, 8.53.
(+)-(1E)-1-[(R)-p -Tolylsu lfin yl]-4-(t r iet h ylsilyl)b u t -1-
en -3-yn e (15d ). Yield: 87%. [R]D ) +177.8 (c 1.67, CHCl3);
1H NMR (400 MHz) δ 0.61 (q, 6H, J ) 7.9 Hz), 0.98 (t, 9H, J
) 7.9 Hz), 2.41 (s, 3H), 6.50 (d, 1H, J ) 15.1 Hz), 6.75 (d, 1H,
15.3 Hz), 7.32 (d, 2H, J ) 8.1 Hz), 7.51 (d, 2H, J ) 8.2
Hz); 13C NMR (100 MHz) δ 4.0, 7.3, 21.4, 100.76, 100.82,
115.6, 124.9, 130.2, 139.5, 142.2, 145.6. Anal. Calcd for
C17H24OSSi: C, 67.05; H, 7.94. Found: C, 66.91; H, 8.02.
(-)-(1Z)-1-[(R)-p -Tolylsu lfin yl]oct -1-en -3-yn e
(17a ).
Yield: 60%. [R]D ) -373.1 (c 1.08, CHCl3); 1H NMR (200 MHz)
δ 0.94 (t, 3H, J ) 7.0 Hz), 1.38-1.56 (m, 4H), 2.40 (s, 3H),
2.44 (td, 2H, J ) 6.0, 2.0 Hz), 6.06 (dt, 1H, J ) 9.7, 2.2 Hz),
6.48 (d, 1H, J ) 9.7 Hz), 7.31 (d, 2H, J ) 8.0 Hz), 7.58 (d, 2H,
J ) 8.2 Hz); 13C NMR (50 MHz) δ 13.4, 19.3, 21.3, 21.8, 0.2,
75.2, 102.5, 118.0, 123.8, 129.9, 141.2, 141.3, 146.1. Anal.
Calcd for C15H18OS: C, 73.13; H, 7.36. Found: C, 73.41; H,
7.54.
(-)-(1Z)-1-[(R)-p-Tolylsu lfin yl]-8-ter t-bu toxyoct-1-en -3-
yn e (17b). Yield: 74%. [R]D ) -598.4 (c 0.62, CHCl3); 1H
NMR (200 MHz) δ 1.18 (s, 9H), 1.60-1.76 (m, 4H), 2.41 (s,
3H), 2.41-2.55 (m, 2H), 3.37-3.41 (m, 2H), 6.06 (dt, 1H, J )
9.7, 2.3 Hz), 6.48 (d, 1H, J ) 9.7 Hz), 7.31 (d, 2H, J ) 7.9 Hz),
7.58 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 19.6, 21.3, 25.2,
27.5, 29.8, 60.8, 72.5, 75.4, 102.4, 118.0, 124.0, 129.9, 141.3,
146.2. Anal. Calcd for C19H24O2S: C, 72.11; H, 7.64. Found:
C, 72.41; H, 7.81.
(-)-(1Z)-1-[(R)-p-Tolylsu lfin yl]-5-[(ter t-bu tyld im eth yl-
silyl)oxy]p en t-1-en -3-yn e (17c). Yield: 75%. [R]D ) -484.6
(c 0.39, CHCl3); 1H NMR (200 MHz) δ 0.11 (s, 6H), 0.93 (s,
9H), 2.41 (s, 3H), 4.55 (s, 2H), 6.10 (d, 2H, J ) 9.8 Hz), 6.56
(d, 2H, J ) 9.9 Hz), 7.32 (d, 2H, J ) 7.9 Hz), 7.59 (d, 2H, J )
8.0 Hz); 13C NMR (50 MHz) δ -5.1, 18.2, 21.3, 25.7, 52.1, 78.9,
99.1, 116.7, 124.0, 130.0, 141.0, 141.5, 147.7. Anal. Calcd for
C18H26O2SSi: C, 64.62; H, 7.83. Found: C, 64.44; H, 7.89.
(-)-(1Z)-1-[(R)-p -Tolylsu lfin yl]-4-(t r iet h ylsilyl)b u t -1-
en -3-yn e (17d ). Yield: 87%. [R]D ) -885.1 (c 0.47, CHCl3);
1H NMR (200 MHz) δ 0.68 (q, 6H, J ) 7.3 Hz), 1.04 (t, 9H, J
) 7.8 Hz), 2.41 (s, 3H), 6.06 (d, 1H, J ) 9.9 Hz), 6.58 (d, 1H,
J ) 9.8 Hz), 7.31 (d, 2H, J ) 7.9 Hz), 7.60 (d, 2H, J ) 7.9 Hz);
13C NMR (50 MHz) δ 4.0, 7.3, 21.3, 99.3, 105.0, 116.7, 123.8,
129.9, 141.0, 141.4, 148.6. Anal. Calcd for C17H24OSSi: C,
67.05; H, 7.94. Found: C, 66.88; H, 8.02.
(1E,3Z)-1-[(R)-p-Tolylsu lfin yl]-1,3-p en ta d ien -5-ol (16a )
a n d (+)-(1E,3Z)-5-Acetoxy-1-[(R)-p-tolylsu lfin yl]-1,3-p en -
ta d ien e. To a benzene (2 mL) solution of sulfinyl enyne 15a
(22 mg, 0.10 mmol) was added RhCl(PPh3)3 (3 mg, 14 wt %).
The flask was placed under a hydrogen atmosphere (1 atm)
and stirred at room temperature for 14 h. The solution was
filtered through Celite to remove the catalyst and concentrated
in vacuo; the crude material was chromatographed (silica gel,
hexane/EtOAc, 19:1 to 5:1) to afford 16a (13.6 mg, 63%) as a
colorless oil. 1H NMR (400 MHz) δ 2.37 (s, 3H), 4.41 (d, 2H,
J ) 6.2 Hz), 5.88 (dt, 1H, J ) 11.0, 6.1 Hz), 6.10 (app t, 1H, J
) 11.1 Hz), 6.31 (d, 1H, J ) 14.8 Hz), 7.2 (obscured, 1H), 7.30
(d, 2H, J ) 8.2 Hz), 7.51 (d, 2H, J ) 8.2 Hz). Since alcohol
16a could not be obtained in analytically pure form, it was
characterized by conversion to its corresponding acetate (Ac2O,
1
10 equiv; pyridine): [R]D ) +267.1 (c 1.81, CHCl3); H NMR
(400 MHz) δ 2.08 (s, 3H), 2.39 (s, 3H), 4.82 (m, 2H), 5.81 (dt,
1H, J ) 10.7, 6.9 Hz), 6.22 (app t, 1H, J ) 11.2 Hz), 6.40 (d,
1H, J ) 14.7 Hz), 7.25 (partially obscured ddd, J ) 14.7, 11.5,
(-)-(1Z)-1-[(R)-p-Tolylsu lfin yl]-5,5-d ieth oxyp en t-1-en -
0.9 Hz), 7.30 (d, 2H, J ) 8.1 Hz), 7.50 (d, 2H, J ) 8.1 Hz); 13
C
3-yn e (17e). Yield: 82%. [R]D ) -738.6 (c 0.44, CHCl3); H
1
NMR (100 MHz) δ 20.8, 21.3, 60.0, 124.7, 128.2, 129.1, 130.1,
NMR (200 MHz) δ 1.27 (t, 6H, J ) 7.0 Hz), 2.41 (s, 3H), 3.58-

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6339
3.87 (m, 4H), 4.47 (s, 1H), 6.10 (d, 1H, J ) 9.8 Hz), 6.64 (d,
1H, J ) 9.9 Hz), 7.32 (d, 2H, J ) 7.8 Hz), 7.59 (d, 2H, J ) 7.2
Hz); 13C NMR (50 MHz) δ 15.0, 21.3, 61.2, 78.8, 91.5, 95.1,
115.6, 123.9, 130.1, 140.6, 141.7, 149.2. Anal. Calcd for
C16H20O3S: C, 65.72; H, 6.89. Found: C, 65.95; H, 7.02.
0.088 mmol). The reaction was stirred under an argon
atmosphere at room temperature for 3 h and then diluted with
EtOAc (4 mL) and washed with a saturated aqueous Na2S2O3
solution (2 mL). The layers were separated, and the aqueous
phase was extracted with EtOAc (3 × 2 mL). The combined
organic layers were washed with brine (2 mL), dried (MgSO4),
filtered, and concentrated in vacuo. The crude material was
purified by two successive gradient chromatographies in order
to remove traces of n-Bu3SnI (silica gel, hexane/EtOAc, 19:1
to 3:1) to afford 18 (27.1 mg, 95%) as a white solid.
(-)-(1Z)-1-[(R)-p -Tolylsu lfin yl]b u t -1-en -3-yn e
(17f).
Yield: 60%. [R]D ) -676.9 (c 0.13, CHCl3); 1H NMR (200 MHz)
δ 2.41 (s, 3H), 3.54 (dd, 1H, J ) 2.5, 0.7 Hz), 6.05 (dd, 1H, J
) 10.0, 2.5 Hz), 6.66 (dd, 1H, J ) 9.9, 0.6 Hz), 7.33 (d, 2H, J
) 8.0 Hz), 7.60 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 21.3,
77.4, 88.1, 115.7, 124.0, 130.1, 140.8, 141.7, 150.0. Anal. Calcd
for C11H10OS: C, 69.44; H, 5.30. Found: C, 69.31; H, 5.18.
(-)-(1Z)-1-[(R )-p -Tolylsu lfin yl]-4-p h e n ylb u t -1-e n -3-
yn e (17g). Yield: 66%. [R]D ) -653.1 (c 0.81, CHCl3); 1H
NMR (200 MHz) δ 2.40 (s, 3H), 6.28 (d, 1H, J ) 9.8 Hz), 6.62
(d, 1H, J ) 9.8 Hz), 7.28 (d, 2H, J ) 7.6 Hz), 7.36-7.39 (m,
3H), 7.50-7.53 (m, 2H), 7.62 (d, 2H, J ) 8.1 Hz); 13C NMR
(50 MHz) δ 21.3, 83.6, 100.7, 117.0, 121.9, 124.0, 128.5, 129.4,
130.0, 131.8, 141.2, 141.5, 147.3. Anal. Calcd for C17H14OS:
C, 76.66; H, 5.30. Found: C, 76.82; H, 5.22.
Gen er a l P r oced u r e for t h e H yd r ost a n n yla t ion of
1-Su lfin yl Alk yn es. Meth od A. To a solution of the alkynyl
sulfoxide in hexane (5 mL/mmol sulfoxide) at room tempera-
ture and under an atmosphere of argon was added a solution
of freshly distilled Bu3SnH (1.1 mL) in hexane (5 mL/mmol
sulfoxide). The reaction mixture was stirred at room temper-
ature for 18 h; the solvent was then removed under reduced
pressure, and the crude material was purified by gradient
chromatography (silica gel, hexane/EtOAc mixtures) to afford
the desired stannylvinyl sulfoxides. Meth od B. To a solution
of the alkynyl sulfoxide (1.0 equiv) in anhydrous toluene (6.6
mL/mmol sulfoxide), at room temperature and under an
atmosphere of argon, was added Pd(PPh3)4 (2 mol %). This
solution was deaerated for 10 min by bubbling argon into the
reaction mixture and was subsequently cooled to a -78 °C. A
solution of freshly distilled Bu3SnH (1.1 equiv) in toluene (1.1
mL/mmol sulfoxide) was then added to the cooled reaction
mixture dropwise via syringe. The reaction mixture was
stirred while the temperature was allowed to warm to ambient
temperature over 2 h. The solvent was then removed at
reduced pressure and the crude material (regioisomeric ratio
(+)-1-Iod o-1-[(S)-p-tolylsu lfin yl]eth en e (18). Meth od
A. (R)-Vinyl p-tolyl sulfoxide (345.3 mg, 2.08 mmol), NIS
(701.0 mg, 3.12 mmol), and 1:1 DMSO/H2O (8 mL) were
combined and stirred overnight at 40 °C. After cooling to room
temperature, EtOAc (50 mL) was then added and the layers
were separated; the aqueous layer was extracted with ad-
ditional EtOAc (2 × 20 mL), and the combined organic layers
were washed with saturated aqueous Na2S2O3 (50 mL). This
aqueous layer was again extracted with EtOAc (50 mL), and
the combined organic layers were dried (MgSO4), filtered, and
concentrated in vacuo. The crude product was purified by
column chromatography (silica gel, hexane/EtOAc, 2:1 to 1:1)
to afford the corresponding iodohydrin (623.8 mg, 96%) as an
inseparable mixture of diastereomers (5.8:1). The iodohydrins
(519.5 mg, 1.68 mmol) were dissolved in CH2Cl2 (17 mL), and
the solution was cooled to 0 °C. After addition of mesyl
chloride (0.13 mL, 1.68 mmol) and triethylamine (0.23 mL,
1.68 mmol), the reaction mixture was stirred under argon for
1 h. Saturated aqueous NH4Cl (10 mL) and H2O (3 mL) were
then added, and the layers were separated. The aqueous layer
was extracted with CH2Cl2 (10 mL) and the combined organic
layers were dried (MgSO4), filtered, and concentrated in vacuo
to afford the iodo mesylate (651.6 mg, 100%) which was used
without further purification. This mesylate was dissolved in
CH2Cl2 (17 mL) and DBU (0.32 mL, 2.16 mmol) was added
dropwise via syringe. The reaction mixture was stirred under
argon at room temperature for 20 min. Saturated aqueous
NH4Cl (10 mL) and H2O (3 mL) were then added, and the
layers were separated. The aqueous layer was extracted with
CH2Cl2 (2 × 10 mL), and the combined organic layers were
dried (MgSO4), filtered, and concentrated in vacuo. The crude
product was purified by column chromatography (silica gel,
hexane/EtOAc, 3:1) to afford iodovinyl sulfoxide 18 (441.7 mg,
90%) as a white solid (mp 82-83 °C). [R]D ) +68.2 (c 1.35,
CHCl3), 1H NMR (400 MHz) δ 2.41 (s, 3H), 6.52 (d, 1H, J )
3.2 Hz), 7.31 (d, 2H, J ) 8.2 Hz), 7.39 (d, 1H, J ) 3.2 Hz),
7.55 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz) δ 21.1, 116.9,
125.3, 129.4, 130.0, 138.6, 142.0. Anal. Calcd for C9H9IOS:
C, 37.00; H, 3.10. Found: C, 37.08; H, 3.02.
Meth od B. Via (+)-(S)-1-(Tr i-n -bu tylsta n n yl)-1-(p-tolyl-
su lfin yl)eth en e (19). To a solution of alkynyl sulfoxide 314
(16.4 mg, 0.10 mmol) in benzene (1 mL) at room temperature
and under an atmosphere of argon was added a solution of
freshly distilled Bu3SnH (34 µL, 0.11 mmol) in benzene (1 mL).
The reaction mixture was stirred at room temperature for 18
h; the solvent was then removed under reduced pressure, and
the crude material was purified by gradient chromatography
(silica gel, hexane/EtOAc, 19:1 to 6:1) to afford 19 (40 mg, 88%)
as a colorless oil. [R]D ) +48.6 (c 2.31, CHCl3); 1H NMR (200
MHz) δ 0.65-0.85 (m, 15H), 1.10-1.35 (m, 12H), 2.36 (s, 3H),
5.95 (s with tin satellites, 1H), 6.71 (s with tin satellites, 1H),
7.24 (d, 2H, J ) 8.0 Hz), 7.45 (d, 2H, J ) 8.2 Hz); 13C NMR
(50 MHz) δ 10.5, 13.5, 21.3, 27.1, 28.6, 125.8, 128.9, 129.8,
141.2, 141.3, 160.9. Anal. Calcd for C21H36OSSn: C, 55.40;
H, 7.97. Found: C, 55.59; H, 7.87. Stannylvinyl sulfoxide 19
was dissolved in THF (1 mL) and treated with NIS (19.8 mg,
1
determined by H NMR integration) was purified by gradient
chromatography (silica gel, hexane/EtOAc mixtures) to afford
the desired stannylvinyl sulfoxides.
(+)-(S)-(1Z)-1-(Tr i-n -bu tylsta n n yl)-1-(p-tolylsu lfin yl)-1-
h exen e (20) a n d (-)-(S)-(1E)-1-(tr i-n -bu tylsta n n yl)-1-(p-
tolylsu lfin yl)-1-h exen e (21). Yield (method A): 20, 75%; 21,
10%. Data for 20: [R]D ) +1.9 (c 5.02, CHCl3); 1H NMR (300
MHz) δ 0.70-1.00 (m, 15H), 0.94 (t, 3H, J ) 7.1 Hz), 1.16-
1.53 (m, 16H), 2.26 (app q, 2H, J ) 7.3 Hz), 2.38 (s, 3H), 7.14
(t with tin satellites, 1H, J ) 7.4 Hz), 7.24 (d, 2H, J ) 8.2
Hz), 7.43 (d, 2H, J ) 8.2 Hz); 13C NMR (75 MHz) δ 11.3, 13.5,
13.9, 14.6, 21.5, 26.4, 27.1, 27.7, 28.5, 28.7, 28.9, 31.5, 33.8,
126.0, 129.5, 140.7, 141.9, 148.6, 149.4. Anal. Calcd for
C25H44OSSn: C, 58.57; H, 8.66; S, 6.24. Found: C, 58.23; H,
9.23; S, 5.98.
(-)-(S)-(1E)-1-(Tr i-n -bu t ylst a n n yl)-1-(p-t olylsu lfin yl)-
1-h exen e (21) a n d (-)-(R)-(1E)-2-(Tr i-n -bu tylsta n n yl)-1-
(p-tolylsu lfin yl)-1-h exen e (23). Yield (method B): 21, 85%;
1
23, 1%. Data for 21: [R]D ) -57.4 (c 2.62, CHCl3); H NMR
(300 MHz) δ 0.78-0.95 (m, 15H), 0.92 (t, 3H, J ) 7.2 Hz),
0.94-1.46 (m, 16H), 2.36 (m, 1H), 2.36 (s, 3H), 2.68 (m, 1H),
6.16 (dd with tin satellites, 1H, J ) 8.6, 5.7 Hz), 7.23 (d, 2H,
J ) 8.1 Hz), 7.39 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ
11.3, 13.5, 13.8, 21.2, 22.2, 27.2, 28.7, 31.3, 32.6, 124.4, 129.5,
139.9, 142.6, 149.0, 156.2. Anal. Calcd for C25H44SOSn: C,
58.72; H, 8.67; S, 6.27. Found: C, 58.43; H, 8.73; S, 5.98. Data
1
for 23: [R]D ) -77.6 (c 3.25, CHCl3); H NMR (300 MHz) δ
0.81-1.05 (m, 18 H), 1.17-1.52 (m, 16H), 2.37 (s, 3H), 2.74
(m, 2H), 6.15 (t with tin satellites, 1H, J ) 1.1 Hz), 7.26 (d,
2H, J ) 8.1 Hz), 7.46 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz)
δ 10.2, 13.5, 13.8, 21.2, 22.6, 27.2, 28.8, 32.2, 35.3, 124.2, 129.8,
140.6, 142.2, 143.2, 161.2. Anal. Calcd for C25H44OSSn: C,
58.72; H, 8.67; S, 6.27. Found: C, 58.56; H, 8.89; S, 6.03.
(-)-(S)-(1E)-1-(Tr i-n -bu tylsta n n yl-1-(p-tolylsu lfin yl)-6-
[(p -m et h oxyb en zyl)oxy]-1-h exen e (26). Yield (method
1
B): 83%. [R]D ) -41.4 (c 1.79, CHCl3); H NMR (CDCl3, 300
MHz) δ 0.73-0.91 (m, 15H), 1.13-1.41 (m, 12H), 1.53-1.68
(m, 4H), 2.35 (s, 3H), 2.38 (m, 1H), 2.68 (m, 1H), 3.45 (t, 2H,
J ) 6.0 Hz), 3.76 (s, 3H), 4.41 (s, 2H), 6.15 (dd with tin
satellites, 1H, J ) 8.6, 5.7 Hz), 6.85 (d, 2H, J ) 8.7 Hz), 7.23
(m, 4H), 7.37 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ 11.4,
13.5, 21.2, 26.0, 27.2, 28.7, 29.2, 32.6, 55.2, 69.5, 72.5, 113.7,
124.4, 129.2, 129.5, 130.6, 139.9, 142.5, 148.6, 156.6, 159.1.
Anal. Calcd for C33H52O3SSn: C, 61.21; H, 8.09. Found: C,
61.02; H, 7.96.

6340 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
Gen er a l P r oced u r e for th e Con ver sion of (1Z)-Sta n -
for the synthesis of 29b,c,e until the disapperance of the
starting sulfoxide, as judged by TLC (approximately 2 h). The
reaction mixture was then treated with a saturated aqueous
KF (3 mL per mmol) and diluted with EtOAc (10 mL per
mmol). The layers were separated, and the aqueous phase
was extracted with EtOAc (three times, 10 mL per mmol), and
the combined organic layers were washed with brine (3 mL
per mmol), dried (MgSO4), filtered, and concentrated in vacuo.
The crude material was purified by gradient chromatography
using hexane/EtOAc mixtures. The elimination of traces of
n-Bu3SnI frequently required a second chromatography. Diene
29a was prepared using the Pd(CH3CN)2Cl2/DMF method, (see
method B for 1-sulfinyl diene synthesis), with added BHT (1
equiv).
(+)-(R)-2-(p-Tolylsu lfin yl)-1,3-bu ta d ien e (29a ). Yield:
70%. [R]D ) +168 (c 1.79, EtOH); 1H NMR (400 MHz) δ 2.39
(s, 3H), 5.20 (d, 1H, J ) 11.3 Hz), 5.46 (d, 1H, J ) 17.7 Hz),
5.85 (s, 1H), 6.12 (s, 1H), 6.22 (dd, 1H, J ) 17.7, 11.3 Hz),
7.26 (d, 2H, J ) 8.2 Hz), 7.53 (d, 2H, J ) 8.2 Hz); 13C NMR
(100 MHz) δ 21.4, 117.1, 119.0, 125.7, 129.4, 129.9, 139.7,
142.0, 151.1. 29a was not stable enough for characterization
by combustion analysis.
n ylvin yl Su lfoxid es in to (1Z)-Iod ovin yl Su lfoxid es.
A
THF (6.75 mL/mmol sulfoxide) solution of the stannyl sulfoxide
(1.0 equiv) was treated with NIS (1.0 equiv). The reaction was
stirred under an argon atmosphere at room temperature for
3 h and then diluted with EtOAc and washed with a saturated
aqueous Na2S2O3 solution. The layers were separated, and
the aqueous phase was extracted with EtOAc. The combined
organic layers were washed with brine, dried (MgSO4), filtered,
and concentrated in vacuo. The crude material was purified
by two successive gradient chromatographies in order to
remove traces of n-Bu3SnI (silica gel, hexane/EtOAc mixtures)
to afford the desired iodovinyl sulfoxides.
(+)-(S)-(1Z)-1-Iod o-1-(p -t olylsu lfin yl)-1-h exen e (22).
Yield: 91%. [R]D ) +29.6 (c 2.57, CHCl3); 1H NMR (300 MHz)
δ 0.91 (t, 3H, J ) 7.2 Hz), 1.37 (m, 2H), 1.44-1.52 (m, 2H),
2.32 (m, 2H), 2.37 (s, 3H), 7.05 (t, 1H, J ) 7.1 Hz), 7.27 (d,
2H, J ) 8.1 Hz), 7.47 (d, 2H, J ) 8.1 Hz); 13C NMR (50 MHz)
δ 13.8, 21.4, 22.2, 29.8, 35.0, 115.1, 125.5, 129.7, 139.9, 141.9,
145.1. Anal. Calcd for C13H17OSI: C, 44.84; H, 4.92; S, 9.21.
Found: C, 44.91; H, 5.06; S, 8.94.
(-)-(S)-(1E)-1-Iod o-1-(p -t olylsu lfin yl)-1-h exen e (24).
Yield: 94%. [R]D ) -94.4 (c 1.86, CHCl3); 1H NMR (200 MHz)
δ 0.96 (t, 3H, J ) 7.2 Hz), 1.36-1.58 (m, 4H), 2.39 (s, 3H),
2.57 (dq, 1H, J ) 14.6, 7.1 Hz), 2.79 (ddt, 1H, J ) 14.6, 8.7,
7.1 Hz), 6.86 (dd, 1H, J ) 8.7, 7.1 Hz), 7.29 (d, 2H, J ) 8.5
Hz), 7.43 (d, 2H, J ) 8.4 Hz); 13C NMR (50 MHz) δ 13.7, 21.4,
22.1, 30.9, 33.3, 114.3, 124.3, 129.7, 140.0, 141.6, 151.9. Anal.
Calcd for C13H17OSI: C, 44.84; H, 4.92; S, 9.21. Found: C,
45.43; H, 4.39; S, 8.74.
(-)-(S)-(1E)-1-Iod o-1-(p -t olylsu lfin yl)-6-[(p -m et h oxy-
ben zyl)oxy]-1-h exen e (27). Yield: 86%. [R]D ) -70.0 (c
2.56, CHCl3); 1H NMR (200 MHz) δ 1.63 (m, 4H), 2.38 (s,
3H), 2.61 (dq, 1H, J ) 14.5, 7.1 Hz), 2.83 (dt, 1H, J ) 14.5,
8.7, 7.1 Hz), 3.48 (t, 2H, J ) 5.9 Hz), 3.78 (s, 3H), 4.43 (s,
2H), 6.85 (dd, 1H, J ) 8.4, 7.1 Hz), 6.88 (d, 2H, J ) 8.6
Hz), 7.22 (m, 4H), 7.41 (d, 2H, J ) 8.4 Hz); 13C NMR (50 MHz)
δ 21.4, 25.7, 29.0, 33.3, 55.2, 69.2, 72.6, 113.8, 114.7, 124.4,
129.2, 129.8, 130.5, 140.0, 141.6, 151.6, 159.2. Anal. Calcd
for C21H25O3SI: C, 52.03; H, 5.16; S, 6.60. Found: C, 52.10;
H, 5.19; S, 6.51.
(+)-(R)-(3E)-3-(p -t olylsu lfin yl)-1,3-oct a d ien e
(29b ).
Yield: 89%. [R]D ) +108.0 (c 1.58, CHCl3); 1H NMR (200 MHz)
δ 0.91 (t, 3H, J ) 7.2 Hz), 1.25-1.60 (m, 4H), 2.34 (q, 2H, J )
7.3 Hz), 2.38 (s, 3H), 5.25 (dt, 1H, J ) 11.5, 1.0 Hz), 5.38 (d,
1H, J ) 17.8 Hz), 6.29 (dd, 1H, J ) 17.8, 11.6 Hz), 6.53 (t, 1H,
J ) 7.7 Hz), 7.25 (d, 2H, J ) 8.1 Hz), 7.50 (d, 2H, J ) 8.2
Hz); 13C NMR (50 MHz) δ 13.8, 21.3, 22.3, 27.9, 31.1, 119.8,
125.6, 126.7, 129.7, 135.4, 140.8, 141.3, 141.4. Anal. Calcd
for C15H20OS: C, 72.54; H, 8.12; S, 12.91. Found: C, 72.28;
H, 7.98; S, 12.64.
(+)-(R)-(1E,3E)-1-P h en yl-3-(p-tolylsu lfin yl)-1,3-octa d i-
en e (29c). Yield: 77%. [R]D ) +6.3 (c 1.51, CHCl3); 1H NMR
(200 MHz) δ 0.92 (t, 3H, J ) 7.1 Hz), 1.25-1.60 (m, 4H), 2.34
(s, 3H), 2.40 (q, 2H, J ) 7.2 Hz), 6.56 (t, 1H, J ) 7.7 Hz), 6.66
(d, 1H, J ) 16.6 Hz), 6.79 (d, 1H, J ) 16.6 Hz), 7.19-7.31 (m,
7H), 7.52 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 13.8, 21.3,
22.3, 28.2, 31.2, 118.4, 125.4, 126.5, 128.3, 128.6, 129.8, 133.6,
135.3, 136.4, 140.9, 141.0, 141.4. Anal. Calcd for C21H24OS:
C, 77.73; H, 7.45. Found: C, 77.59; H, 7.56.
(-)-(R)-(3Z)-3-(p -t olylsu lfin yl)-1,3-oct a d ien e
(29d ).
(-)-(S)-(1E)-1-Iod o-1-(p -t olylsu lfin yl)-2-m et h yl-1-h ex-
en e (28). To a suspension of CuI (76 mg, 0.40 mmol) in THF
(4 mL) under an argon atmosphere at 0 °C was added MeLi
(0.26 mL, 1.58 M Et2O, 0.40 mmol) dropwise via syringe, and
the resulting colorless mixture was stirred for 10 min. The
solution was then cooled to -78 °C; a solution of alkynyl
sulfoxide 5 (46 mg, 0.20 mmol) in THF (2 mL) was slowly
added dropwise via syringe. The resulting yellow solution was
stirred at -78 °C for 30 min and then NIS (90 mg, 0.40 mmol)
in THF (2 mL) was rapidly added and the resulting mixture
was stirred for an additional 30 min. After treatment with a
saturated solution of Na2S2O3 (2 mL), the temperature was
allowed to rise to 20 °C when the mixture was then diluted
with EtOAc (10 mL). The aqueous layer was extracted with
EtOAc (3 × 4 mL), and the combined organic layers were
washed with brine (2 mL), dried (MgSO4), filtered, and
concentrated in vacuo. The crude reaction material was
purified by chromatography (silica gel, hexane/EtOAc, 19:1 to
Yield: 80%. [R]D ) -299.2 (c 0.95, CHCl3); 1H NMR (300 MHz)
δ 0.94 (t, 3H, J ) 7.2 Hz), 1.37-1.56 (m, 4H), 2.37 (s, 3H),
2.51 (m, 1H), 2.71 (m, 1H), 5.11 (dd, 1H, J ) 11.0, 1.4 Hz),
5.48 (dd, 1H, J ) 17.4), 6.17 (dd, 1H, J ) 17.4, 11.0 Hz), 6.26
(t, 1H, J ) 7.6 Hz), 7.26 (d, 2H, J ) 8.1 Hz), 7.41 (d, 2H, J )
8.3 Hz); 13C NMR (50 MHz) δ 13.8, 21.2, 22.3, 28.4, 31.5, 118.2,
124.2, 128.3, 129.7, 138.5, 139.9, 140.5, 143.1. Anal. Calcd
for C15H20OS: C, 72.54; H, 8.12; S, 12.91. Found: C, 72.19;
H, 7.85; S, 12.65.
(-)-(R)-(1Z,3E)-1,1-Dieth oxy-4-(p-tolylsu lfin yl)-2,4-n on -
a d ien e (29e). Yield: 59%. [R]D ) -64.7 (c 1.04, CHCl3); H
1
NMR (400 MHz) δ 0.94 (t, 3H, J ) 7.2 Hz), 1.06 (t, 3H, J )
7.2 Hz), 1.13 (t, 3H, J ) 7.2 Hz), 1.47 (m, 4H), 2.37 (s, 3H),
2.53 (app sextet, 1H), 2.72 (app sextet, 1H), 3.18-3.52 (m, 4H),
4.79 (d, 1H, J ) 5.1 Hz), 5.89 (dd, 1H, J ) 16.0, 5.1 Hz), 6.22
(d, 1H, J ) 16.0 Hz), 6.30 (t, 1H, J ) 7.9 Hz), 7.25 (d, 2H, J )
8.5 Hz), 7.40 (d, 2 H, J ) 8.2 Hz); 13
C NMR (100 MHz) δ 13.8,
15.01, 15.05, 21.2, 22.3, 28.6, 31.4, 60.5, 61.1, 100.7, 124.16,
124.24, 129.6, 130.7, 139.5, 139.7, 140.4, 141.7. Anal. Calcd
6:1) to afford 28 (46 mg, 61%) as a pale yellow oil. [R]D
)
1
-82.2 (c 4.64, CHCl3); H NMR (200 MHz) δ 0.95 (t, 3H, J )
7.2 Hz), 1.36-1.70 (m, 4H), 2.10 (s, 3H), 2.37 (s, 3H), 2.75-
3.00 (m, 2H), 7.26 (d, 2H, J ) 8.2 Hz), 7.39 (d, 2H, J ) 8.4
Hz); 13C NMR (50 MHz) δ 13.8, 21.4, 22.5, 29.9, 30.8, 37.1,
115.6, 124.6, 129.7, 141.0, 141.2, 157.1. HRMS Calcd for
C14H19OSI: 362.0201. Found: 362.0211.
for C20
(-)-(R)-(1Z)-1-[4-[(p -Met h oxyb en zyl)oxy]b u t yl]-2-(p -
tolylsu lfin yl)-1,3-bu ta d ien e (29f). Yield: 59%. [R]D
H30O3S: C, 68.53; H, 8.63. Found: C, 68.75; H, 8.84.
)
1
-133.1 (c 1.40, CHCl3); H NMR (200 MHz) δ 1.50-1.64 (m,
4H), 2.32 (s, 3H), 2.53 (m, 1H), 2.64 (m, 1H), 3.42 (t, 2H, J )
5.8 Hz), 3.73 (s, 3H), 4.37 (s, 2H), 5.07 (dd, 2H, J ) 11.1, 1.2
Hz), 5.43 (dd, 2H, J ) 17.4, 1.2 Hz), 6.12 (dd, 1H, J ) 17.4,
11.1 Hz), 6.19 (t, 1H, J ) 7.7 Hz), 6.80 (d, 2H, J ) 8.7 Hz),
7.18 (m, 4H), 7.35 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ
21.3, 26.2, 28.5, 29.3, 55.3, 69.5, 72.7, 77.2, 113.8, 118.4, 124.3,
128.3, 129.2, 129.8, 130.6, 138.1, 139.9, 140.6, 143.4, 159.2.
Anal. Calcd for C23H28O3S: C, 71.84; H, 7.34. Found: C,
72.05; H, 7.56.
Gen er a l P r oced u r e for th e P r ep a r a tion of 2-Su lfin yl
1,3-Dien es. To a solution of 1 equiv of the 1-iodovinyl
sulfoxide in anhydrous THF (10 mL/mmol sulfoxide) at room
temperature and under an argon atmosphere were added
Ph3As (20 mol %), 2,6-di-tert-butyl-4-methylphenol (BHT) (1
equiv), and the corresponding vinylstannane. After deaerating
the solution by bubbling argon into the reaction mixture for
10 min, Pd2(dba)3‚CHCl3 (5 mol %) was added. The resulting
mixture was heated to reflux (bath temperature, 70 °C) for
the synthesis of 29d ,f,g or was stirred at room temperature
(-)-(R )-(3Z)-4-Me t h yl-3-(p -t olylsu lfin yl)-1,3-oct a d i-
en e (29g). Yield: 81%. [R]D ) -193.1 (c 0.77, CHCl3); 1H

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6341
NMR (300 MHz) δ 0.94 (t, 3H, J ) 7.2 Hz), 1.37-1.61 (m, 4H),
1.94 (d, 3H, J ) 0.7 Hz), 2.36 (s, 3H), 2.67 (t, 2H, J ) 7.7 Hz),
5.27 (dd, 1H, J ) 17.4, 1.9 Hz), 5.29 (dd, 1H, J ) 11.7, 1.9
Hz), 5.98 (ddd, 1H, J ) 17.3, 11.2, 0.6 Hz), 7.24 (d, 2H, J )
8.0 Hz), 7.37 (d, 2H, J ) 8.3 Hz); 13C NMR (50 MHz) δ 13.9,
20.8, 21.3, 22.8, 29.7, 31.0, 34.8, 122.5, 124.5, 126.7, 129.5,
138.0, 140.1, 140.3, 149.1. HRMS Calcd for: C16H22OS:
262.1391. Found: 262.1383.
η4-r-[(RS)-2-(p -Tolylsu lfin yl)-1,3-b u t a d ien e]t r ica r b o-
n ylir on (0) Com p lex (30d ). Yield (method A): 30d , 45% of
an inseparable 1.2:1 mixture of diastereomers. Data for
diastereomeric mixture: 1H NMR (CDCl3, 200 MHz) δ 0.13-
0.32 (m + dd, total 1H), 1.88-2.08 (m + dd, total 1H), 2.26-
2.50 (m, total 2H), 2.43 (s, 3H), 5.65 + 6.03 (2m, total 1H),
7.35 (d, total 2H, J ) 8.0 Hz), 7.67 (d, total 2H, J ) 8.2 Hz).
(-)-η4-r-[(RS)-(1Z,3E)-5,5-Diet h oxy-1-(p-t olylsu lfin yl)-
1,3-p en ta d ien e]tr ica r bon ylir on (0) Com p lex (30e) a n d Its
â-Isom er . Yield (method B): R-30e, 75%; â-30e, 4.7%. Data
Gen er a l P r oced u r e for th e Syn th esis of Su lfin yl Dien e
Ir on (0) Com p lexes. Meth od A. To a solution of the sulfinyl
diene in THF or Et2O (0.05-0.10 M) at room temperature and
under an argon atmosphere was added Fe2(CO)9 (3.0 equiv).
The mixture was refluxed for 24 h and then cooled, and the
resulting brown mixture was filtered through silica gel; the
filter cake was washed with copious amounts of EtOAc. After
the filtrate was concentrated in vacuo, the residue was purified
by chromatography (silica gel, hexane/EtOAc). Meth od B. To
a solution of the sulfinyl diene in THF (0.05 M) at 0 °C and
under an argon atmosphere was added NMO (6.0 equiv). To
this suspension was added Fe(CO)5 (3.0 equiv) dropwise via
syringe; a purple color formed initially, but became brown as
the addition of the Fe(CO)5 neared completion. The resulting
mixture was stirred at 0 °C for 1.5 h, then was placed in a
preheated (80 °C) oil bath and stirred for an additional 1.5 h.
After cooling, the mixture was filtered through silica gel; the
filter cake was washed with copious amounts of EtOAc. After
the filtrate was concentrated in vacuo, the residue was purified
by chromatography (silica gel, hexane/EtOAc). Meth od C. To
a solution of the sulfinyl diene in toluene (0.05 M) at room
temperature and under an argon atmosphere was added
1
for R-30e: [R]D ) -14.3 (c 0.79, CHCl3); H NMR (500 MHz)
δ 1.22 (t, 3H, J ) 7.0 Hz), 1.23 (t, 3H, J ) 7.0 Hz), 2.37 (s,
3H), 2.94 (dd, 1H, J ) 9.0, 3.7 Hz), 3.37 (dd, 1H, J ) 6.8, 1.1
Hz), 3.53-3.59 (m, 2H), 3.69-3.76 (m, 2H), 4.69 (d, 1H, J )
3.9 Hz), 5.05 (ddd, 1H, J ) 7.1, 5.2, 1.1 Hz), 5.77 (dd, 1H, J )
9.0, 5.1 Hz), 7.26 (d, 2H, J ) 8.3 Hz) 7.35 (d, 2H, J ) 8.1 Hz);
13C NMR (50 MHz) δ 15.0, 15.1, 21.3, 61.2, 62.3, 63.8, 76.7,
77.4, 93.5, 101.3, 123.2, 129.8 140.7, 146.3. Anal. Calcd for
C19H22O6SFe: C, 52.55; H, 5.11; S, 7.38. Found: C, 52.68; H,
5.06; S, 7.42. Data for â-30e: [R]D ) -33.8 (c 0.42, CHCl3);
1H NMR (500 MHz) δ 1.21 (t, 3H, J ) 7.1 Hz), 1.22 (t, 3H, J
) 7.1 Hz), 2.41 (s, 3H), 3.18 (ddd, 1H, J ) 9.3, 3.9, 0.9 Hz),
3.49-3.58 (m, 2H), 3.53 (dd, 1H, J ) 7.1, 1.1 Hz), 3.68-3.76
(m, 2H), 4.63 (d, 1H, J ) 3.9 Hz), 5.39 (ddd, 1H, J ) 7.1, 5.3,
1.1 Hz), 5.85 (dd, 1H, J ) 9.3, 5.1 Hz), 7.31 (d, 2H, J ) 8.1
Hz), 7.63 (d, 2H, J ) 8.1 Hz). 13C NMR (50 MHz) δ 15.1, 21.5,
61.3, 62.4, 63.7, 74.1, 94.9, 101.1, 124.9, 130.0, 142.0, 142.8.
(+)-η4-r-[(RS)-(1E,3E)-5,5-Diet h oxy-1-(p-t olylsu lfin yl)-
1,3-p en ta d ien e]tr ica r bon ylir on (0) Com p lex (30f) a n d Its
â-Isom er . Yield (method B): R-30f, 51%; â-30f, 36%. Data
for R-30f: [R]D ) +180.4 (c 1.92, CHCl3); 1H NMR (300 MHz)
δ 1.08 (dd, 1H, J ) 8.5, 4.3 Hz), 1.14 (t, 3H, J ) 7.1 Hz), 1.15
(t, 3H, J ) 7.1 Hz), 1.60 (d, 1H, J ) 7.5 Hz), 2.40 (s, 3H), 3.39-
3.48 (m, 2H), 3.50-3.64 (m, 2H), 4.46 (d, 1H, J ) 4.4 Hz), 5.41
(dd, 1H, J ) 8.6, 5.1 Hz), 5.50 (dd, 1H, J ) 7.8, 5.3 Hz), 7.31
(d, 2H, J ) 8.1 Hz), 7.44 (d, 2H, J ) 8.2 Hz); 13C NMR (50
MHz) δ 15.0, 21.4, 60.4, 60.6, 61.8, 76.5, 78.0, 82.4, 101.4,
123.0, 129.8, 141.2, 143.4. Anal. Calcd for C19H22O6SFe: C,
52.55; H, 5.11; S, 7.38. Found: C, 52.36; H, 4.97; S, 7.21. Data
for â-30f: [R]D ) -109.8 (c 1.64, CHCl3); 1H NMR (300 MHz)
δ 1.14 (t, 6H, J ) 7.1 Hz), 1.31 (ddd, 1H, J ) 8.7, 4.1, 1.1 Hz),
1.74 (dd, 1H, J ) 7.3, 1.0 Hz), 2.40 (s, 3H), 3.36-3.49 (m, 2H),
3.52-3.66 (m, 2H), 4.49 (d, 1H, J ) 4.0 Hz), 5.51 (dd, 1H, J )
8.7, 5.1 Hz), 5.73 (ddd, 1H, J ) 7.3, 5.0, 1.2 Hz), 7.31 (d, 2H,
J ) 8.0 Hz), 7.61 (d, 2H, J ) 8.1 Hz). 13C NMR (50 MHz) δ
15.0, 21.4, 60.9, 62.0, 62.7, 72.0, 79.9, 85.4, 100.9, 124.2, 130.0,
141.9, 142.2. Anal. Calcd for C19H22O6SFe: C, 52.55; H, 5.11;
S, 7.38. Found: C, 52.81; H, 5.30; S, 7.29.
50
(bda)Fe(CO)3 (4.0 equiv). The red solution was placed in a
preheated 45 °C oil bath and stirred at that temperature for
16 h. After cooling, the mixture was filtered through silica
gel; the filter cake was washed with copious amounts of EtOAc.
After the filtrate was concentrated in vacuo, the residue was
purified by chromatography (silica gel, hexane/EtOAc). Usu-
ally 70-75% of the excess (bda)Fe(CO)3 could be recovered by
the chromatography and reused.
(+)-η4-r-[(RS)-(1E)-1-(p -Tolylsu lfin yl)-1,3-b u t a d ien e]-
tr ica r bon ylir on (0) Com p lex (30a ) a n d Its â-Isom er . Yield
(method A): R-30a , 54%; â-30a , 40%. Data for R-30a : [R]D
)
+213.4 (c 1.04, CHCl3); 1H NMR (300 MHz) δ 0.36 (dd, 1H, J
) 9.3, 2.9 Hz), 1.62 (d, 1H, J ) 7.7 Hz), 1.84 (ddd, 1H, J )
6.8, 2.8, 1.1 Hz), 2.41 (s, 3H), 5.29 (m, 1H), 5.64 (dd, 1H, J )
7.7, 4.9 Hz), 7.32 (d, 2H, J ) 8.1 Hz), 7.45 (d, 2H, J ) 8.3 Hz);
13C NMR (50 MHz) δ 21.4, 39.8, 77.4, 81.8, 82.9, 123.0, 129.9,
141.2, 143.5. Anal. Calcd for C14H12FeO4S: C, 50.62; H, 3.64.
Found: C, 50.48; H, 3.55. Data for â-30a : [R]D ) -150.8 (c
3.25, CHCl3); 1H NMR (300 MHz) δ 0.58 (dd, 1H, J ) 9.4, 2.7
Hz), 1.77 (d, 1H, J ) 7.4 Hz), 1.96 (dd, 1H, J ) 6.8, 2.1 Hz),
2.40 (s, 3H), 5.34-5.41 (m, 1H), 5.85-5.89 (m, 1H), 7.31 (d,
2H, J ) 8.0 Hz), 7.61 (d, 2H, J ) 8.1 Hz); 13C NMR (50 MHz)
δ 21.4, 41.5, 72.7, 83.7, 85.8, 124.2, 130.0, 141.9, 142.2.
(-)-η4-r-[(RS)-(1Z)-1-(p -Tolylsu lfin yl)-1,3-b u t a d ien e]-
tr icar bon ylir on (0) Com plex (30b). Yield (method B): R-30b,
(+)-η4-r-[(RS)-(1E,3E)-5,5-Dieth oxy-4-m eth yl-1-(p-tolyl-
su lfin yl)-1,3-pen tadien e]tr icar bon ylir on (0) Com plex (30g)
a n d Its â Isom er . Yield (method B): R-30g, 15%; â-30g, 15%.
1
Data for R-30g: [R]D ) +158.9 (c 1.51, CHCl3); H NMR (400
MHz) δ 1.07 (s, 3H), 1.21 (overlapping triplets, 6H, J ) 7.0
Hz), 2.43 (s, 3H), 2.88 (d, 1H, J ) 8.0 Hz), 3.40-3.73 (m, 4H),
4.06 (s, 1H), 5.28 (d, 1H, J ) 5.3 Hz), 5.57 (dd, 1H, J ) 8.0,
56%; â-30b, 3%. Data for R-30b: mp 118-120 °C; [R]D
)
5.3 Hz), 7.34 (d, 2H, J ) 8.1 Hz), 7.50 (d, 2H, J ) 8.2 Hz); 13
C
-27.8 (c 1.50, CHCl3); 1H NMR (300 MHz) δ 2.18 (dd, 1H, J )
9.7, 3.6 Hz), 2.31-2.35 (m, 1H), 2.37 (s, 3H), 3.43 (d, 1H, J )
7.1 Hz), 5.20 (dd, 1H, J ) 6.8, 5.8 Hz), 5.58-5.65 (m, 1H), 7.25
(d, 2H, J ) 8.1 Hz), 7.35 (d, 2H, J ) 8.2 Hz); 13C NMR (50
MHz) δ 21.3, 43.5, 78.3, 80.8, 94.3, 123.2, 129.9, 140.8, 145.2,
208.1 (CO). Anal. Calcd for C14H12FeO4S: C, 50.62; H, 3.64.
Found: C, 50.79; H, 3.71.
NMR (100 MHz) δ 14.3, 15.0, 15.2, 21.4, 63.4, 63.5, 73.1, 76.8,
81.0, 87.5, 109.0, 123.2, 129.9, 141.1, 143.5. Anal. Calcd for
C20H24O6FeS: C, 53.58; H, 5.40; S, 7.15. Found: C, 53.72; H,
5.56; S, 7.02. Data for â-30g: 1H NMR (400 MHz) δ 1.10 (s,
3H), 1.19 (overlapping triplets, 6H, J ) 6.9 Hz), 2.42 (s, 3H),
3.01 (d, 1H, J ) 7.7 Hz), 3.39-3.71 (m, 4H), 4.08 (s, 1H), 5.36
(d, 1H, J ) 5.3 Hz), 5.82 (dd, 1H, J ) 7.6, 5.3 Hz), 7.33 (d, 2H,
J ) 8.0 Hz), 7.67 (d, 2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ
14.9, 15.2, 21.4, 63.4, 63.8, 72.6, 75.8, 83.1, 89.9, 108.3, 124.3,
130.0, 141.8, 142.1.
(-)-η4-r-[(RS)-(1Z)-2-n -Bu tyl-1-(p-tolylsu lfin yl)-1,3-bu ta-
d ien e]tr ica r bon ylir on (0) Com p lex (30c). Yield (method
B): R-30c, 44%; â-30c, 8% (could not be separated from
1
unreacted sulfinyl diene 10j; weight determined by H NMR
(+)-η4-r-[(RS)-(2E,4Z)-1,1-Diet h oxy-4-(p-t olylsu lfin yl)-
2,4-n on a d ien e]tr ica r bon ylir on (0) Com p lex (30h ). Yield
(method B): R-30h , 34%; â-30h , 25% (could not be separated
integration). Data for R-30c: mp 78-80 °C; [R]D ) -70.0 (c
3.30, CHCl3); 1H NMR (200 MHz) δ 0.76 (t, 3H, J ) 7.2
Hz), 0.89-1.29 (m, 4H), 1.89-2.27 (m, 4H), 2.39 (s, 3H), 3.40
(d, 1H, J ) 1.2 Hz), 5.44 (app t, 1H, J ) 9.0, 8.0 Hz), 7.26 (d,
2H, J ) 8.2 Hz), 7.36 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz)
δ 13.6, 21.3, 22.1, 32.2, 38.1, 40.6, 81.8, 92.4, 102.5, 123.4,
129.8, 141.0, 145.4, 208.4 (br, CO). Anal. Calcd for
C18H20O4SFe: C, 55.68; H, 5.19; S, 8.26. Found: C, 55.43; H,
4.97; S, 8.03.
1
from unreacted sulfinyl diene 29e; weight determined by H
NMR integration). Data for R-30h : [R]D ) +61.0 (c 0.59,
CHCl3); 1H NMR (400 MHz) δ 0.89 (t, 3H, J ) 6.9 Hz +
obscured signal, 1H), 1.01 (dd, 1H, J ) 8.7, 5.0 Hz), 1.22 (t,
6H, J ) 7.0), 1.20-1.37 (partially obscured m, 4H), 1.69-1.78
(m, 2H), 2.44 (s, 3H), 3.51 (m, 2H), 3.66 (m, 2H), 4.50 (d, 1H,
J ) 4.9 Hz), 6.18 (d, 1H, J ) 8.8 Hz), 7.35 (d, 2H, J ) 8.1 Hz),

6342 J . Org. Chem., Vol. 62, No. 18, 1997
Paley et al.
7.69 (d, 2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ 13.8, 15.11,
15.15, 21.6, 22.3, 29.9, 34.3, 58.6, 61.2, 61.4, 62.3, 75.2, 102.2,
107.6, 125.2, 130.2, 142.5. Anal. Calcd for C23H30O6FeS: C,
56.33; H, 6.17; S, 6.54. Found: C, 56.12; H, 6.28; S, 6.71.
(+)-η4-â-[(RS)-(1E)-2-Bu tyl-1-(p-tolylsu lfin yl)-1,3-bu ta -
d ien e]tr ica r bon ylir on (0) Com p lex (30i). Yield (method
C): â-30i, 70%; R-30i, 26% (could not be separated from the
byproduct benzylidene acetone; weight determined by 1H NMR
integration). Data for â-30i: [R]D ) +326.1 (c 0.92, CHCl3);
1H NMR (400 MHz) δ 0.54 (dd, 1H, J ) 9.2, 2.7 Hz), 1.03 (t,
3H, J ) 7.3 Hz), 1.53-1.71 (m, 3H), 1.72 (s, 1H), 1.88 (dd, 1H,
J ) 7.0, 2.8 Hz), 2.04 (m, 1H), 2.43 (s, 3H), 2.58 (m, 1H), 3.03
(m, 1H), 5.22 (app t, 1H, J ) 8.4, 7.8 Hz), 7.34 (d, 2H, J ) 8.0
Hz), 7.69 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz) δ 14.7, 15.0,
30.5, 33.5, 33.6, 40.3, 76.0, 85.5, 107.2, 125.5, 130.8, 142.7,
142.8. Anal. Calcd for C18H20O4FeS: C, 55.68; H, 5.19; S, 8.26.
Found: C, 55.83; H, 5.34; S, 8.04.
was added (recrystallized from H2O, 680 mg, 3.77 mmol). After
2 h the reaction mixture was diluted with Et2O (100 mL) and
washed with a 5% aqueous NaHCO3 solution (3 × 35 mL), H2O
(3 × 35 mL), and brine (60 mL). The organic layer was dried
(MgSO4), filtered, and concentrated in vacuo. The crude
product was purified by chromatography (silica gel, hexane/
EtOAc, 49:1) to afford (E)-1-bromo-5-(1,3-dithiolan-2-yl)-1-
pentene (595 mg, 80%) as a yellow oil. 1H NMR (200 MHz) δ
1.42-1.57 (m, 2H), 1.61-1.81 (m, 2H), 2.03 (q, 2H, J ) 7.0
Hz), 3.07-3.22 (m, 4H), 4.39 (t, 1H, J ) 6.9 Hz), 5.98 (d, 1H,
J ) 14.0 Hz), 6.07 (m, 1H); 13C NMR (50 MHz) δ 27.9, 32.3,
38.3, 38.5, 53.2, 104.7, 137.2. To a solution of (E)-1-bromo-5-
(1,3-dithiolan-2-yl)-1-pentene (200 mg, 0.79 mmol) in dry Et2O
(5.5 mL) at -78 °C under argon atmosphere was added t-BuLi
(0.46 mL of 1.7M solution in pentane, 0.79 mmol) dropwise,
and the resulting solution was stirred at this temperature for
45 min when chlorotributylstannane (0.21 mL, 0.79 mmol) was
added. After an additional 45 min period at -78 °C, the
solution was quenched with a saturated solution of NH4Cl (2
mL). The aqueous phase was extracted with hexane (3 × 3
mL); the combined organic layers were dried (MgSO4) and
concentrated in vacuo to give a crude oil that was distilled
(bulb to bulb distillation) to yield of 32 (292 mg, 80%) as a
colorless oil (bp 180-190 °C @ 0.5 mmHg). 1H NMR (200 MHz)
δ 0.70-1.62 (m, 29H), 1.74-1.86 (m, 2H), 2.09-2.17 (m, 2H),
3.09-3.28 (m, 4H), 4.45 (t, 1H, J ) 6.96 Hz), 5.88 (AB system
with 119Sn satellites, 2H); 13C NMR (50 MHz) δ 9.44, 13.7, 27.2,
28.4, 29.1, 37.3, 38.3, 38.8, 53.7, 128.1, 148.6.
(+)-(1E,3E)-7-F or m yl-1-[(R)-p-tolylsu lfin yl]-1,3-octa d i-
en e (33). To a solution of sulfinyl diene 7i (130 mg, 0.38
mmol) in 7:3 CH3CN/H2O (11 mL) were added HgCl2 (156 mg,
0.58 mmol) and HgO (62 mg, 0.29 mmol), and the resulting
mixture was stirred and heated a reflux for 4 h. After cooling
the reaction to room temperature, the mercury salts were
filtered and rinsed with EtOAc (40 mL). This filtrate was
washed with a 5% aqueous NaHCO3 solution (3 × 20 mL), a
10% aqueous KI solution (10 mL), and brine (10 mL). The
combined aqueous phases were extracted with EtOAc (10 mL),
and the combined organic extracts were dried (MgSO4),
filtered, and concentrated in vacuo. The crude material was
purified by chromatography (silica gel, hexane/EtOAc, 3:1 to
1:1) to afford 33 (92 mg, 92%) as a colorless oil. [R]D ) +112.9
(c 0.78, CHCl3); 1H NMR (200 MHz) δ 1.72 (quint, 2H, J ) 7.3
Hz), 2.20 (q, 2H, J ) 7.0 Hz), 2.40 (s, 3H), 2.46 (app t, 2H, J
) 7.2 Hz), 5.91-6.17 (m, 2H), 6.26 (d, 1H, J ) 15.0 Hz), 6.94
(dd, 1H, J ) 14.9, 9.7 Hz), 7.30 (d, 2H, J ) 8.2 Hz), 7.51 (d,
2H, J ) 8.1 Hz), 9.76 (s, 1H); 13C NMR (50 MHz) δ 20.9, 21.2,
31.8, 42.8, 124.5, 127.7, 129.9, 134.1, 136.2, 140.7, 140.9, 141.3,
201.6. Anal. Calcd for C15H18O2S: C, 68.67; H, 6.91. Found:
C, 68.93; H, 6.70.
(1E ,3E ,8R *,9S*)-8-H yd r oxy-1-[(R )-p -t olylsu lfin yl]-9-
(tr ip h en ylsilyl)-1,3,10-u n d eca tr ien e (35) (m ixtu r e of d i-
a ster eom er s). To a solution of allyl triphenylsilane (268 mg,
0.86 mmol) in anhydrous THF (5 mL) at 0 °C was added
n-BuLi (0.44 mL, 1.6 M in Et2O, 0.71 mmol) dropwise, and
the resulting mixture was stirred at that temperature for 45
min. The mixture was then cooled to -78 °C, and Ti(i-PrO)4
(0.23 mL, 0.77 mmol) was added dropwise; stirring was
continued at -78 °C for an additional 30 min. Simultaneously,
in another reaction flask, aldehyde 33 (150 mg, 0.57 mmol)
and ZnBr2 (170 mg, 0.77 mmol) were dissolved in THF (3 mL),
and this solution was stirred at room temperature for 15 min
before it was transferred via cannula to the solution of the
titanate at -78 °C. The reaction mixture was stirred for 1 h
at -78 °C and was then quenched with a 5% aqueous HCl
solution (2 mL) and diluted with H2O (30 mL) and Et2O (80
mL). The layers were separated, and the aqueous phase was
extracted with Et2O (5 × 10 mL). The combined organic layers
were dried (MgSO4), filtered, and concentrated in vacuo. The
crude material was purified by chromatography (silica gel,
hexane/EtOAc, 9:1 to 5:1) to afford 35 (225 mg, 80%), a mixture
of inseparable diastereomers, as a white solid. The two
diastereomers had identical spectroscopic characteristics by
1H NMR at 200 MHz. 1H NMR (200 MHz) δ 1.24-1.43 (m,
4H), 2.03 (m, 2H), 2.39 (s, 3H), 2.64 (dd, 1H, J ) 10.1, 3.3
Hz), 3.94 (m, 1H), 5.01 (dd, 1H, J ) 17.2, 1.7 Hz), 5.08 (dd,
(-)-η4-â-[(RS)-(1Z)-1-(p -Tolylsu lfin yl)-2-(t r iet h ylsilyl)-
1,3-bu ta d ien e]tr ica r bon yl ir on (0) Com p lex (30j). Yield
(method C): â-30j, 59%; R-30j, 33%. Data for â-30j: [R]D
)
1
-201.3 (c 2.97, CHCl3); H NMR (400 MHz) δ 0.99-1.17 (m,
16H), 1.54 (s, 1H), 2.18 (dd, 1H, J ) 7.0, 2.3 Hz), 2.42 (s, 3H),
5.17 (app t, 1H, J ) 8.5, 7.8 Hz), 7.32 (d, 2H, J ) 7.9 Hz), 7.65
(d, 2H, J ) 8.0 Hz); 13C NMR (100 MHz) δ 5.4, 8.5, 22.3, 47.1,
79.1, 88.7, 92.4, 125.4, 130.7, 142.7, 143.6. Anal. Calcd for
C20H26O4FeSSi: C, 53.81; H, 5.87. Found: C, 54.00; H, 5.64.
(+)-η4-r-[(RS)-(1Z,3E)-3-Bu tyl-1-(p-tolylsu lfin yl)-1,3-pen -
t a d ien -5-ol]t r ica r b on ylir on (0) Com p lex (30k ). Yield
(method B): R-30k , 54%; â-30k , 10%. Data for R-30k : mp
117-119 °C; [R]D ) +28.8 (c 0.70, CHCl3); 1H NMR (400 MHz)
δ 0.98 (t, 3H, J ) 5.7 Hz), 1.41-1.65 (m, 3H), 1.85 (m, 1H),
2.27 (m, 1H), 2.38 (s, 3H), 2.58 (m, 1H), 2.81 (app t, 1H, J )
7.2, 6.7 Hz), 3.12 (br s, 1H), 3.33 (d, 1H, J ) 7.2 Hz), 3.97 (m,
2H), 4.86 (d, 1H, J ) 7.2 Hz), 7.22 (d, 2H, J ) 8.1 Hz), 7.28 (d,
2H, J ) 8.1 Hz); 13C NMR (100 MHz) δ 13.9, 21.3, 22.5, 61.3,
64.2, 75.8, 115.4, 123.1, 129.8, 140.8, 145.0. Anal. Calcd for
C19H22O5FeS: C, 54.56; H, 5.30. Found: C, 54.71; H, 5.44.
(-)-η4-r-[(RS)-(1Z,3E)-3-(Hydr oxym eth yl)-1-(p-tolylsu lfi-
n yl)-5-[(ter t-bu tyld im eth ylsilyl)oxy]-1,3-p en ta d ien e]tr i-
ca r bon ylir on (0) Com p lex (30l). Yield (method B): R-30l,
45%; â-30l, 4%. Data for R-30l: mp 133.5-135 °C; [R]D
)
-17.9 (c 0.74, CHCl3); 1H NMR (400 MHz) δ 0.17 (s, 6H), 0.94
(s, 9H), 2.41 (s, 3H), 2.82 (dd, 1H, J ) 9.7, 5.8), 3.39 (d, 1H, J
) 7.3 Hz), 3.84 (m, 2H), 4.10 (dd, 1H, J ) 11.4, 5.8 Hz), 4.23
(app t, 1H, J ) 12.6, 10.6 Hz), 4.66 (dd, 1H, J ) 12.7, 2.8 Hz),
5.16 (d, 1H, J ) 7.3 Hz), 7.30 (d, 2H, J ) 8.2 Hz), 7.40 (d, 2H,
J ) 8.1 Hz); 13C NMR (100 MHz) δ -5.3, -5.1, 18.2, 21.4, 25.8,
60.1, 62.3, 63.4, 75.7, 79.2, 112.8, 123.3, 130.0, 141.0, 144.9.
Anal. Calcd for C22H30O6FeSSi: C, 52.17; H, 5.97. Found: C,
52.33; H, 6.11.
(-)-η4-r-[(RS)-(1Z,3E)-3-[[(Tr ieth ylsilyl)oxy]m eth yl]-1-
(p-tolylsu lfin yl)-5-[(tr iisop r op ylsilyl)oxy]-1,3-p en ta d ien -
e]tr ica r bon ylir on (0) Com p lex (30m ) a n d Its â-Isom er .
Yield (method C): R-30m , 84%; â-30m , 8%. Data for R-30m :
1
[R]D ) -13.2 (c 1.53, CHCl3); H NMR (400 MHz) δ 0.67 (q,
6H, J ) 7.8 Hz), 0.99 (t, 9H, J ) 8.0 Hz), 1.08-1.18 (m, 21H),
2.40 (s, 3H), 2.83 (t, 1H, J ) 5.5 Hz), 3.39 (d, 1H, J ) 7.4 Hz),
4.03 (ABX system, 2H, J ) 11.7, 7.8, 6.4 Hz), 4.59 (AB system,
2H, J ) 14.2 Hz), 5.34 (d, 1H, J ) 7.3 Hz), 7.28 (d, 2H, J )
7.8 Hz), 7.39 (d, 2H, J ) 8.2 Hz); 13C NMR (100 MHz) δ 5.2,
7.6, 12.8, 18.9, 22.2, 62.0, 62.7, 63.0, 75.9, 76.1, 115.2, 124.1,
130.7, 141.5, 146.3. Anal. Calcd for C28H44O6FeSSi2: C, 54.18;
H, 7.14. Found: C, 54.39; H, 7.10. Data for â-30m : 1H NMR
(400 MHz) δ 0.66 (m, 6H), 1.00 (t, 9H, J ) 7.9 Hz), 1.07-1.17
(m, 21H), 2.44 (s, 3H), 3.12 (t, 1H, J ) 6.6 Hz), 3.55 (d, 1H, J
) 7.1 Hz), 4.03 (ABX system, 2H, J ) 11.9, 6.8, 6.5 Hz), 4.55
(AB system, 2H, J ) 14.0 Hz), 5.65 (d, 1H, J ) 7.1 Hz), 7.33
(d, 2H, J ) 8.1 Hz), 7.65 (d, 2H, J ) 8.1 Hz).
(E)-1-(Tr i-n -bu tylsta n n yl)-6-(1,3-d ith iola n -2-yl)-1-h ex-
en e (32). To a solution of Cp2ZrHCl (Fluka, 900 mg, 3.50
mmol) in anhydrous benzene (25 mL), under an argon atmo-
sphere, was added 2-(4-pentyn-1-yl)-1,3-dithiolane (500 mg,
2.90 mmol) in anhydrous benzene (5 mL). The reaction
mixture was protected from light and submerged into a
preheated 40 °C oil bath and was stirred at that temperature
for 40 min; after cooling to room temperature, anhydrous NBS

Preparation of Sulfinyl Iron(0) Dienes
J . Org. Chem., Vol. 62, No. 18, 1997 6343
1H, J ) 10.3, 1.8 Hz), 5.89-6.08 (m, 3H), 6.17 (d, 1H, J )
14.9 Hz), 6.89 (ddd, 1H, J ) 14.9, 9.8, 2.1 Hz), 7.26-7.41 (m,
11H), 7.49 (d, 2H, J ) 8.2 Hz), 7.57-7.62 (m, 6H); 13C NMR
(50 MHz) δ 21.3, 25.1, 32.3, 36.4, 40.1, 70.8, 117.6, 124.7, 127.1,
127.8, 129.5, 130.0, 133.6, 134.0, 134.6, 136.3, 137.0, 141.2,
141.4, 142.4.
aqueous layer was extracted with EtOAc (5 mL). The com-
bined organic layers were dried (MgSO4), filtered, and con-
centrated in vacuo. The resulting crude material was purified
by chromatography (silica gel, hexane/EtOAc, 5:1) to afford
(8E)-31 (54 mg, 93%) as a colorless oil. An analysis of the
1
crude reaction material by H NMR revealed the presence of
(+)-(1E,3E,8Z)-1-[(R)-p-Tolylsu lfin yl]-1,3,8,10-u n decatet-
r a en e [(8Z)-31]. To a solution of the hydroxysilanes 35 (68
mg, 0.121 mmol) in THF (3 mL) at 0 °C was added Kt-OBu
(14 mg, 0.13 mmol). After stirring for 10 min, the reaction
mixture was diluted with H2O (5 mL) and Et2O (25 mL); the
layers were separated, and the aqueous layer was extracted
with Et2O (2 × 10 mL). The combined organic layers were
dried (MgSO4), filtered, and concentrated in vacuo. The
resulting crude material was purified by chromatography
(silica gel, hexane/EtOAc, 5:1) to afford (8Z)-31 (33 mg, 100%)
as a colorless oil. None of the other isomer, (8E)-31, could be
detected by 1H NMR (200 MHz) of the crude reaction mixture.
[R]D ) +103.5 (c 0.34, CHCl3); 1H NMR (200 MHz) δ 1.49
(quint, 2H, J ) 7.3 Hz), 2.05-2.23 (m, 4H), 2.37 (s, 3H), 5.05
(dd, 1H, J ) 10.1, 1.7 Hz), 5.16 (dd, 1H, J ) 16.8, 1.7 Hz), 5.38
(dt, 1 H, J ) 10.5, 7.6 Hz), 5.93-6.07 (m, 3H), 6.18 (d, 1H, J
) 14.9 Hz), 6.57 (dt, 1H, J ) 16.8, 10.1 Hz), 6.92 (dd, 1H, J )
14.9, 9.8 Hz), 7.27 (d, 2H, J ) 8.3 Hz), 7.48 (d, 2H, J ) 8.2
Hz); 13C NMR (50 MHz) δ 21.3, 27.0, 28.5, 32.2, 117.1, 124.7,
127.3, 129.8, 130.0, 131.8, 132.1, 133.7, 137.0, 141.2, 141.4,
142.2. Anal. Calcd for C18H22OS: C, 75.48; H, 7.74. Found:
C, 75.77; H, 7.70.
the (8Z) isomer (<5%, calculated by integration of signal from
H8 at 5.38 ppm), inseparable from the major (8E)-isomer. 1H
NMR (200 MHz) δ 1.49 (quint, 2H, J ) 7.3 Hz), 2.02-2.18 (m,
4H), 2.38 (s, 3H), 4.94 (dd, 1H, J ) 10.1, 1.0), 5.06 (dd, 1H, J
) 16.8, 1.0 Hz), 5.64 (dt, 1H, J ) 15.1, 6.9 Hz), 5.95-6.08 (m,
3H), 6.20 (d, 1H, J ) 15.1 Hz), 6.28 (dt, 1H, J ) 16.8, 10.1
Hz), 6.92 (dd, 1H, J ) 15.0, 9.9 Hz), 7.28 (d, 2H, J ) 8.0 Hz),
7.49 (d, 2H, J ) 8.2 Hz); 13C NMR (50 MHz) δ 21.3, 28.2, 31.9,
32.2, 115.0, 124.7, 127.3, 130.0, 131.5, 133.7, 134.3, 137.1,
141.2, 141.4, 142.5.
Ack n ow led gm en t. We thank the donors of the
Petroleum Research Fund, administered by the Ameri-
can Chemical Society (Grant 26064-B1), Research Corp.
(Grant C-3763), and DGICYT (Grants PB93-0154 and
PB94-0104). R.S.P. is an American Cyanamid Faculty
Awardee. A.dD. and C.M. thank the Comunidad de
Madrid for doctoral and visiting fellowships.
Su p p or tin g In for m a tion Ava ila ble: Complete experi-
mental procedures, 1H NMR peak assignments, and IR and
MS data for all new compounds (45 pages). This material is
contained in libraries on microfiche, immediately follows this
article in the microfilm version of the journal, and can be
ordered from the ACS; see any current masthead page for
ordering information.
(1E,3E,8E)-1-[(R)-p -Tolylsu lfin yl]-1,3,8,10-u n d eca t et -
r a en e [(8E)-31]. To a solution of hydroxysilane 35 (114 mg,
0.20 mmol) in anhydrous CH2Cl2 (2 mL) at -78 °C was added
catalytic quantities of BF3‚OEt2, and the resulting mixture was
stirred for 2 h. The solution was then treated with a 5%
aqueous NaHCO3 solution (1 mL) and diluted with H2O (2 mL)
and EtOAc (10 mL); the layers were separated, and the
J O970693A