General method for preparation of allenic zinc reagents by three-carbon homologation of triorganozincates: Convergent three-component coupling of propargylic substrates, triorganozincates, and electrophilic reagents

Article abstract of DOI:10.1021/ja962136w

Allenic zinc reagents (R¹R²C=C=C(R³)ZnL) are efficiently prepared by the reaction of propargylic substrates (R¹R²C(X)C≡CH, X = MeSO₂O,Cl, R₂NCO₂) with a variety of tri

Full text of DOI:10.1021/ja962136w

J. Am. Chem. Soc. 1996, 118, 11377-11390
11377
General Method for Preparation of Allenic Zinc Reagents by
Three-Carbon Homologation of Triorganozincates: Convergent
Three-Component Coupling of Propargylic Substrates,
Triorganozincates, and Electrophilic Reagents
Toshiro Harada,* Takeshi Katsuhira, Atsushi Osada, Katsuhiro Iwazaki,
Keiji Maejima, and Akira Oku
Contribution from the Department of Chemistry, Kyoto Institute of Technology,
Matsugasaki, Sakyo-ku, Kyoto 606, Japan
ReceiVed June 24, 1996X
Abstract: Allenic zinc reagents (R1R2CdCdC(R3)ZnL) are efficiently prepared by the reaction of propargylic
substrates (R1R2C(X)CtCH, X ) MeSO2O, Cl, R2NCO2) with a variety of triorganozincates ((R3)3ZnM; R3 )
alkyl, alkenyl, aryl, M ) Li, MgCl). Treatment of the allenic zinc reagents with D2O gives the corresponding
deuteroallenes with high deuterium incorporation. The allenic zinc reagents thus prepared undergo a coupling reaction
with a variety of electrophiles (aldehydes, acyl chlorides, I2, NCS, and chlorosilanes) regioselectively at the γ position
to afford the corresponding propargylic derivatives (R1R2C(El)CtCR3, El ) RCH(OH), RCO, I, Cl, R3Si) in high
yields. Silicon containing allenic zinc reagents R1CHdCdC(CH2SiMe3)ZnL and R1CHdCdC(SiPhMe2)ZnL are
readily prepared by the reaction of propargylic carbamates (R1CH(OCONPh2)CtCH) with (TMSCH2)3ZnLi and by
the reaction of bromoproparglic mesylates R1CH(OSO2Me)CtCBr with (PhMe2Si)3ZnLi, respectively. Successive
treatment of these reagents with electrophiles affords functionalized organosilicon compounds of high synthetic utility.
Homologation of organometallics is of increasing importance
in organic synthesis because subsequent bond formation of the
resulting organometallics leads to a convergent construction of
complex carbon frameworks by a one-pot procedure. The
synthetic potential has been demonstrated, for example, in recent
development of useful carbon-carbon bond forming reactions
using carbometalation of alkynes1 and in three-component
coupling approaches to a prostaglandin synthesis via conjugate
addition/alkylation sequence.2 While carbometalation and
conjugate addition lead to a two-carbon homologation of
organometallics, one-carbon homologation or methylene inser-
tion is achieved by 1,2-migration of ate-type carbenoids (Scheme
1). Recently, we have shown that homologation of triorga-
nozincates via 1,2-migration of zincate carbenoids are utilized
in preparation of alkenyl-,3 cyclopropyl,4 and alkylzinc reagents.5
Numerous other examples of one-carbon homologation via ate-
type carbenoids other than zincates have also been reported.6
Previously, Zweifel7 and Midland8 reported independently
1,2-migration of alkynylborates derived from propargyl acetates
and chlorides (eq 1). In this reaction, 1,2-migration takes place
with simultaneous liberation of the leaving groups at the γ
position to generate allenic borons. We envisioned that a novel
three-carbon homologation of triorganozincate could be devel-
X Abstract published in AdVance ACS Abstracts, November 1, 1996.
(1) Knochel, P. In ComprehensiVe Organic Synthesis; Trost, B. M.,
Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 4, pp 865-911.
(2) (a) Suzuki, M.; Yanagisawa, A.; Noyori, R. J. Am. Chem. Soc. 1988,
110, 4718. (b) Morita, Y.; Suzuki, M.; Noyori, R. J. Org. Chem. 1989, 54,
1785. (c) Takahashi, T.; Nakazawa, M.; Kanoh, M.; Yamamoto, K.
Tetrahedron Lett. 1990, 31, 7349. (d) Lipshutz, B. H.; Wood, M. R. J. Am.
Chem. Soc. 1994, 116, 11689-11702.
(3) (a) Harada, T.; Hara, D.; Hattori, K.; Oku, A. Tetrahedron Lett. 1988,
29, 3821-3824. (b) Harada, T.; Katsuhira, T.; Kotani, Y.; Maejima, R.;
Oku, A. J. Org. Chem. 1993, 58, 4897.
(4) (a) Harada, T.; Hattori, K.; Katsuhira, T.; Oku, A. Tetrahedron Lett.
1989, 30, 6039-6040. (b) Harada, T.; Katsuhira, T.; Hattori, K.; Oku, A.
Tetrahedron Lett. 1989, 30, 6035-6038. (c) Harada, T.; Katsuhira, T.;
Hattori, K.; Oku, A. J. Org. Chem. 1993, 58, 2958.
Scheme 1
oped by utilizing possible 1,2-migration of alkynylzincates 2
(Scheme 2). Indeed, we found that (1) such alkynylzincates
can be generated simply by the reaction of propargylic substrates
1 with triorganozincate, (2) the resulting alkynylzincates 2
undergo facile 1,2-migration to give allenic zinc 3, and (3) the
allenic zinc 3 undergo coupling reaction with a variety of
electrophiles regioselectively at the γ positions to give prop-
(6) (a) Negishi, E.; Akiyoshi, K. J. Am. Chem. Soc. 1988, 110, 646. (b)
Negishi, E.; Akiyoshi, K.; O’Connor, B.; Takagi, K.; Wu, G. J. Am. Chem.
Soc. 1989, 111, 3089. (c) Knochel, P.; Jeong, N.; Rozema, M. J.; Yeh, M.
C. P. J. Am. Chem. Soc. 1989, 111, 6474. (d) Knochel, P.; Chou, T.-S.;
Chen, H. G.; Yeh, M. C. P.; Rozema, M. J. J. Org. Chem. 1989, 54, 5202.
(e) Knochel, P.; AchyuthaRao, S. J. Am. Chem. Soc. 1990, 112, 6146. (f)
Rozema, M. J.; Knochel, P. Tetrahedron Lett. 1991, 32, 1855. (g)
AchyuthaRao, S.; Knochel, P. J. Am. Chem. Soc. 1992, 114, 7579. (h)
AchyuthaRao, S.; Rosema, M. J.; Knochel, P. J. Org. Chem. 1993, 58,
2694. (i) Matteson, D. S.; Mah, R. W. H. J. Am. Chem. Soc. 1963, 85,
2599. (j) Danheiser, R. L.; Savoca, A. C. J. Org. Chem. 1985, 50, 2401.
(k) Birkinshaw, S.; Kocienski, P. Tetrahedron Lett. 1991, 47, 6961. (l)
Brown, H. C.; Soundarajan, R. Tetrahedron Lett. 1994, 35, 6963. (m)
Soundarajan, R.; Li, G.; Brown, H. C. Tetrahedron Lett. 1994, 35, 8957.
(n) Soundarajan, R.; Li, G.; Brown, H. C. Tetrahedron Lett. 1994, 35, 8961.
(o) Miller, J. A. J. Org. Chem. 1989, 54, 998. (p) Kitatani, K.; Hiyama, T.;
Nozaki, H. Bull. Chem. Soc. Jpn. 1977, 50, 1600 and 2158. (q) Kocienski,
P.; Wadman. S.; Cooper, K. J. Am. Chem. Soc. 1989, 111, 2363. (r)
Kocienski, P.; Dixon, N. J. Synlett 1989, 52. (s) Stocks, M.; Kocienski, P.;
Donald, K. K. Tetrahedron Lett. 1990, 31, 1637.
(7) (a) Leung, T.; Zweifel, G. J. Am. Chem. Soc. 1974, 96, 5620. (b)
Zweifel, G.; Backlund, S. J.; Leung, T. J. Am. Chem. Soc. 1978, 100, 5561.
(8) Midland, M. M. J. Org. Chem. 1977, 42, 2650.
(5) Harada, T.; Katsuhira, T.; Kotani, Y.; Oku, A. Tetrahedron Lett. 1991,
32, 1573.
S0002-7863(96)02136-1 CCC: $12.00 © 1996 American Chemical Society

11378 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
Scheme 2.
The reaction of mesylate 1a with 2.0 equiv of Bu3ZnLi
afforded [5-2H]-5a with high deuterium incorporation in almost
quantitative yield, demonstrating the high-yield formation of
allenic zinc 3a (entry 1). The level of deuterium incorporation
was dropped considerably when 1.3 equiv of the zincate was
used (entry 2). Control of the reaction temperatures was also
influential; the rapid warming of the reaction mixture (conditions
A) gave a better result in comparison with the slow warming
(conditions B) (entries 1 vs 3). Other propargylic derivatives
such as chloride 1b, phosphate 1c, and carbamates 1d,e also
afforded allenic zinc 3a with varying efficiencies (entries 4-9).
Of these, N,N-diphenylcarbamate 1d exhibited notably high
yield of allenic zinc 3a comparable to mesylate 1a. No allene
formation was observed in the reaction of the methoxy and
TBSO derivatives 1f,g (entries 10 and 11).
Table 1. Preparation of Allenic Zinc 3a by the Reaction of
Propargylic Derivatives 1a-g with Bu3ZnLia
equiv of
yield of d-content yield of
entry substrate Bu3ZnLi conditions 5a (%)
(%)
3a (%)b
The scope of the reaction with respect to the structures of
organozincates was investigated by using mesylate 1a as a
substrate (eq 3 and Table 2). A series of lithium trialkylzincates
(R3 ) Me, Bu, s-Bu, and t-Bu) was successfully used in the
preparation of the corresponding homologated allenic zinc
(entries 1-6). Three equiv of Me3ZnLi were necessary for the
successful preparation of 3b (entries 3 and 4). Allenic zinc 3e
and 3f bearing alkenyl and aryl groups, respectively, were also
prepared by using the corresponding lithium zincates (entries 7
and 8). Chloromagnesium zincate obtained by the reaction of
BuMgCl with ZnCl2 reacted similarly with slightly lower
efficiency than the lithium zincate (entry 2).
1
2
1a
2.0
1.3
2.0
2.0
1.3
2.0
2.0
1.3
2.0
2.0
2.0
A
A
B
A
A
A
C
C
C
A
A
97
72
88
97
86
81
90
71
55
0
92
52
89
37
80
79
48
72
86
67
26
3
91
4
1b
81
5
56
6
1c
1d
89
7
>95
>95
64
8
9
1e
1f
1g
10c
11c
0
a The substrate and the zincate were first mixed at -85 °C. Before
the addition of D2O, the mixture was stirred for 15 min at 0 °C
(conditions A), allowed to warm slowly from -85 to 0 °C over 1-3
h (conditions B), or stirred at -15 °C for 15 min and then at rt for
1-2 h (conditions C). b The yield of allenic zinc 3a estimated based
on the yield and deuterium content of allene 5a. c [1-2H]-1f,g of >99%
deuterium content were recovered in 94% and 91% yield, respectively,
in entries 10 and 11.
argylic derivatives 4, providing an efficient one-pot method for
introduction of a nucleophile (R1) and an electrophile (El) to
the propargylic substrates 1 at the 1,3-positions.
In this paper, we wish to report on the scope and limitation
of the three-carbon homologation of triorganozincates and its
application to the convergent three-component coupling syn-
thesis of propargylic derivatives.9
Allenic organometals often exists as equilibrating mixture
with isomeric propargylic species.10 Equilibration between
allenic and propargylic zinc bromides has been studied previ-
ously.11 Direct evidence for the formation of allenic zinc 3a
was provided by FTIR analysis of the reaction mixture of 1a
and Bu3ZnLi (2.0 equiv). Thus, the mixture showed a strong
Results and Discussion
Preparation of Allenic Zinc Reagents. Reactions were
carried out for a series of 5-phenyl-1-pentyne-3-ol derivatives
1a-g and Bu3ZnLi in THF at temperatures from -85 °C to 0
°C (or to rt) (eq 2, Table 1). The reaction was quenched with
D2O and the yield of allenic zinc 3a was estimated based on
the yield and deuterium content of allene [5-2H]-5a.
band due to the vibration νas (CdCdC) at 1890 cm-1 10a,11
band due to ν (CtC) was observed in the region 2250-2100
cm-1
The result supports our assumption that allene 5 is
.
No
.
produced by protonation of allenic zinc 3 through an SE2
pathway. In the reaction using simple triorganozincates, forma-
tion of alkyne 7 was negligible (<3%). On the other hand, the
reactions using the sterically demanding s-Bu3ZnLi and t-Bu3-
ZnLi afforded alkynes 7c,d as minor products (entries 5 and
6). The IR spectrum of the reaction mixture of 1a and t-Bu3-
ZnLi (2.0 equiv) showed a weak absorption (ν (CtC)) at 2158
(10) (a) Moreau, J.-L. Organometallic DeriVatiVes of Allenes and
Ketenes. In The Chemistry of Ketenes, Allenes, and Related Compounds;
Patai, S., Ed.; Interscience: New York, 1980. (b) Epsztein, R. The Formation
and Transformations of Allenic and Acetylenic Carbanions. In Compre-
hensiVe Carbanion Chemistry, Vol. 5b; Elsevier: Amsterdam, 1984.
(11) Moreau, J.-L.; Gaudemar, M. Bull. Soc. Chime. Fr. 1970, 2171 and
1973, 2549.
(9) Preliminary communication of this work has appeared: (a) Katsuhira,
T.; Harada, T.; Maejima, K.; Osada, A.; Oku, A. J. Org. Chem. 1993, 58,
6166. (b) Harada. T. Osada, A.; Oku, A. Tetrahedron Lett. 1995, 36, 723.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11379
Table 2. Generation of Allenic Zinc 3 by the Reaction of Propargylic Derivatives 1 and Triorganozincatesa
a Unless otherwise noted, all reactions were performed using 2.0 equiv of zincates under conditions A in Table 1. b Unless otherwise noted,
e
yields refer to isolated yields. c Combined yield of 5a (66%) and 1-phenyl-4-nonyne (7a) (6%). d 3.0 Equiv of the zincate was used. Combined
yield of 5c (86%) and 3-methyl-8-phenyl-4-octyne (7c) (6%). f Combined yield of 5d (60%) and 2,2-dimethyl-7-phenyl-3-heptyne (7d) (16%).g For
structures of 11-13, see Scheme 3. h The reaction mixture was quenched by the addition of H2O. i The reaction was perfumed under conditions C
in Table 1. j Combined yield of 5a (71%) and 7a (11%). k The reaction was perfumed under conditions B in Table 1. l GC yield.
cm-1 together with a strong absorption (νas (CdCdC)) at 1892
cm-1 10a,11
suggesting that allenic zinc 3d is in equilibrium with
when Et2(Ph)ZnLi and Et2(2-thienyl)ZnLi was used. The
reaction of Et2(Ph)ZnLi, in particular, afforded the corresponding
allenic zinc 3g in satisfactory yield (77%) judging from 88%
deuterium incorporation in 5g. In spite of the low level of
deuterium incorporation, the high-yield formation of 5g by using
Et2(t-BuO)ZnK is also noteworthy.
As shown in entries 17-23, a variety of allenic zinc reagents
including those bearing siloxy and acetal moieties were suc-
cessfully prepared by the reaction of the corresponding prop-
argylic substrates. The reaction of tertiary propargylic chloride
1m yielded trisubstituted allenic zinc 5m in an efficient manner.
With the combination of propargylic substrates and organozin-
cates, a wide range of allenic zinc reagents are available. It
has been reported that allenic zinc reagents were prepared by
lithiation of the corresponding allenes13 or alkynes (R1-
CH2CtCR3)14 followed by transmetalation. Application of the
method to the preparation of 1,3-disubstituted derivatives 3 (R2
) H) would unavoidably result in nonselective formation of a
mixture of the regioisomers. The present reaction allows such
allenic zinc species to be prepared in a regiospecific manner.
,
its propargylic form 6d. It is probable that alkyne 7d was
produced from 6d through an SE2 pathway. Interestingly,
judging from the D2O quench experiment (entry 7), organozinc
species generated by the reaction of (CH2dC(Me))3ZnLi appears
to exist as allenic zinc 3e in spite of a possible isomerization to
propargylic zinc 6e and butatrienylmethylzinc 8 (eq 4).
We briefly investigated the reaction of mixed zincates Et2-
(R)ZnM (entries 9-12).12 The mixed zincates were prepared
by treatment of Et2Zn with an equivalent of RM and used in
the reaction of 1a. Although a mixture of [5-2H]-5g (R3 ) Et)
and [5-2H]-5c (R3 ) s-Bu) was produced in the reaction of Et2-
(s-Bu)ZnLi, the selective formation of [5-2H]-5g was observed
(13) (a) Ishiguro, M.; Ikeda, N.; Yamamoto, H. J. Org. Chem. 1982, 47,
2225. (b) Haruta, R.; Ishiguro, M.; Ikeda, N.; Yamamoto, H, J. Am. Chem.
Soc. 1982, 104, 7667. (c) Furuta, K.; Ishiguro, M.; Haruta, R.; Ikeda, N.;
Yamamoto, H. Bull Chem. Soc. Jpn. 1984, 57, 2768. (d) Kobayashi, S.;
Nishio, K. J. Am. Chem. Soc. 1995, 117, 6392.
(12) (a) Tuckmantel, W.; Oshima, K.; Nozaki, H. Chem. Ber. 1986, 119,
104. (b) Kjomaas, R. A.; Vawter, E. J. J. Org. Chem. 1986, 51, 3993.
(14) Zweifel, G.; Hahn, G. J. Org. Chem. 1984, 49, 4565.

11380 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
In most instances, deuterium contents of allenes [2H]-5 were
less than 100%, indicating formation of protonated allenes 5 as
byproducts in the reaction mixture before treatment with D2O.
In the course of the reaction, initially formed allenic zinc 3A
reacts reversibly with a triorganozincate to form more basic
allenic zincate 3B (eq 6).16 Protonation of allenic zincate 3B
by remaining substrate 1 may explain the formation of the
protonated allene. This was confirmed by the reaction of the
labeled chloride [1-2H]-1m (eq 7); the reaction gave allene
[2-2H]-5m with 32% deuterium incorporation in 92% yield.
Table 3. Reaction of Propargylic Derivatives with Bu3ZnLi (2.0
Equiv) at Low Temperatures
temp
(°C)
time
(min)
yield (%)
(d-content (%))
entry
substrate
1
5a
1
2
3
4
1d
1e
1a
1b
-15
-15
-60
-40
15
15
30
30
99 (100)
98 (100)
5 (0)
90 (93)
66 (91)
33 (10)
Scheme 3. (R ) PhCH2CH2)
The undesirable protonation pathway via 3B may compete
significantly in the reaction using 1.3 equiv of zincates.
Employment of 2.0 (or 3.0) equiv of zincates may effectively
retard the pathway especially in the later phase of the reaction
leading to the high-yield formation of allenic zinc 3. It should
be noted that in the reaction of carbamates 1d,e, however, the
substrates were completely converted to the alkynylzincates 2
before they undergo an 1,2-migration and, therefore, the
intervention of such pathway is infeasible. Indeed, the reaction
of 1d using 1.3 equiv of Bu3ZnLi gave 5a with >95% deuterium
incorporation (Table 1, entry 8). Use of excess amount of
zincates is also advantageous for obtaining higher yields of
allene 5.
Internal alkyne PhCH2CH2CH(OMs)CtCCH3 (1n) did not
react at all with Bu3ZnLi under similar conditions. Treatment
of allene 5a with Bu3ZnLi (2.0 equiv) at 0 °C for 1 h and D2O
quench of the reaction resulted in the recovery of 5a (98%)
without deuterium incorporation. These observations exclude
the formation of allenic zinc 3 via a mechanism involving the
initial formation of allene 5 via SN2′ pathway followed by
regioselective metalation by a zincate (eq 5). Quantitative
deuterium incorporation in the recovered starting material
observed in the reaction of 1f,g (Table 1, entries 10 and 11)
shows that zincates are basic enough to abstract acetylenic
protons. Therefore, the formation of allenic zinc 3 most
probably proceeded through a mechanism involving initial
metalation of propargylic derivatives by zincates and sub-
sequent 1,2-alkyl migration of the resulting alkynylzincates 2
(Scheme 2).
In the reaction of 1a with t-Bu3ZnLi, several minor products
were obtained other than allene 5d (Scheme 3). Allenic zinc
3d with the sterically demanding tert-butyl group isomerized
considerably to propargylic zinc 6d, leading to the formation
of 5d and 7d in 52% and 16% yield, respectively. The
formation of reduction products 11 (5%) and 12 (7%) suggests
the generation of allenic zinc 9 and propargylic zinc 10 in the
reaction mixture. Their formation are most reasonably explained
by a mechanism involving hydride migration from alkynylzin-
cate intermediate 2d with simultaneous elimination of isobutene.
Hydride reduction has been often observed in the reaction of
tert-butylmetals.18 The present observation, however, is a first
example of such reactivity for the zincates. Finally, alkyne 13
(6%), a formal 1,4-migration product of alkynylzincate 2d, was
also obtained in this reaction.
Evidence for the intermediacy of alkynylzincate 2 was
provided by D2O-quench experiments at low temperatures
(Table 3). Treatment of diphenylcarbamate 1d with Bu3ZnLi
at -15 °C for 15 min followed by the addition of D2O afforded
[1-2H]-1d with >95% deuterium incorporation without forma-
tion of allene 5a (entry 1). Upon warming up to rt, alkynylz-
incate 2d, generated under these conditions, was converted to
allenic zinc 3a (Table 1, entry 7). A similar result was obtained
for diethylcarbamate 1e (Table 3, entry 2 and Table 1, entry 9).
In contrast to the carbamates, mesylate 1a afforded allenic zinc
3a even at -60 °C and no deuterium was found in the recovered
1a (entry 3). An intermediate result was obtained for chloride
1m (entry 4). The 1,2-migration is a rate determining step for
1d,e with less reactive carbamoyloxy groups. On the other
hand, proton abstraction is a rate determining step for mesylate
1a with a good leaving group. Both steps are of comparable
rates in the reaction of chloride 1m.15
Reaction of Allenic Zinc 3 with Aldehydes: Stereoselective
Synthesis of anti-Homopropargylic Alcohols. The reaction
(15) The nature of leaving groups in 1 also influences to the acidity of
acetylenic proton. Thus, deprotonation of mesylate 1a proceeded even at
-60 °C judging from 90% yield formation of allene 5a (entry 3). On the
other hand, deprotonation of carbamate 1d did not proceed in appreciable
rate at the same temperature.
(16) Assuming
a
rapid ligand transfer,17 organozincates [R1(R2)-
CdCdC(R3)]n(R3)3-nZnLi (n ) 2, 3) as well as diorganozinc [R1(R2)-
CdCdC(R3)]2Zn (n ) 0-2) should also be present in the reaction mixture.
Although these organozinc species were neglected in order to simplify the
discussion, the same conclusion are deduced by considering these species.
(17) (a) Seitz, L. M.; Brown, T. L. J. Am. Chem. Soc. 1966, 88, 4140.
(b) Seitz, L. M.; Brown, T. L. J. Am. Chem. Soc. 1967, 89, 1602. (c) Seitz,
L. M.; Little, B. F. J. Organomet. Chem. 1969, 18, 227.
(18) (a) Harada, T. Maeda, H.; Oku, A. Tetrahedron Lett. 1985, 26, 6489.
(b) Ritter, R. H.; Cohen, T. J. Am. Chem. Soc. 1986, 108, 3718. (c) Topolsk,
M.; Duraisamy, M.; Rachon, J.; Gawronski, J.; Gawronska, K.; Geoedken,
V.; Walborsky, H. M. J. Org. Chem. 1993, 58, 546.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11381
of allenic metal reagents with aldehydes gives homopropargylic
alcohols and/or R-allenic alcohols depending on the nature of
the metal atoms.10 Success in control of the regioselectivity
reported recently made the reaction as an efficient and useful
method for the extension of the carbon chains.13 Zweifel et al.
have previously reported the selective formation of homopro-
pargylic alcohols in the reaction of aldehydes with 3-substituted
allenic chlorozinc reagents.14 The reaction is also stereoselective
affording the anti isomer with high stereoselectivity. We found
that a variety of anti-homopropargylic alcohols 14 were prepared
convergently by a successive treatment of propargylic deriva-
tives 1 with triorganozincates and aldehydes in one-pot (eq 8).
Scheme 4
the synthesis of highly functionalized homopropargylic alcohols
such as 14p, 14s, and 14t.
The reaction proceeded regioselectively not only for 1,3-
disubstituted allenic zincs but also for trisubstituted allenic zincs
(entries 21 and 22). A notable exception for the regioselectivity
was observed in the reaction of parent propargyl mesylate (1o).
The reaction of 1o with Bu3ZnLi and aldehydes resulted in the
formation of R-allenic alcohols 15w,x in preference to ho-
mopropargylic alcohols 14w,x (entries 23 and 24).
We first examined the direct reaction of allenic zinc 3h (R1
) C8H17, R2 ) H, R3 ) Bu), prepared by the reaction of
mesylate 1h and Bu3ZnLi (2 equiv), with 3-phenylpropanal (eq
9). However, the reaction resulted in the nonselective formation
of homopropargylic alcohol 14a (anti:syn ) 55:45) and R-allenic
alcohol 15a. Both regio- and stereoselectivity were improved
dramatically when allenic zinc 3h was treated with ZnCl2 before
the addition of the aldehyde. Thus, treatment of 3h with ZnCl2
(3.0 equiv) at -85 °C followed by the addition of 3-phenyl-
propanal (1.5 equiv) yielded stereoselectively anti-homoprop-
argylic alcohols 14a without formation of allenic alcohol 15a.
It should be noted that the formation of 3-phenyl-3-heptanol
which would arise by butylation of the aldehyde was not
observed in this reaction.
The nature of the coordination state of zinc atoms in allenic
zinc species influences much to the mode of addition (SE2′ vs
SE2) and the stereoselectivity. The direct use of allenic zinc
reagent 3h without treatment with ZnCl2 resulted in nonselective
formation of 14a and 15a (eq 9). Because 2 equiv of Bu3ZnLi
were employed in generation of 3h, the reagents most probably
existed as a equilibrating mixture of diorganozinc 3A and zincate
3B (eq 6). By the addition of 3 equiv of ZnCl2, the mixture
was converted to allenic chlorozinc species 3C, whose reaction
with aldehydes proceeded regio- and stereoselectively. The
addition of 0.5 equiv of ZnCl2 may lead to the formation of
diorganozinc 3A. Interestingly, reaction using such organozinc
species afforded homopropargylic alcohols 14a regioselectively
but with lower stereoselectivity (89:11) (eq 10). By comparing
the result with that of the direct use of 3h (a mixture of 3A and
3B), it can be deduced that zincates 3B participated preferentially
in the nonselective reaction with the aldehyde.20 Of three types
of allenic zinc species, chlorozinc 3C and diorganozinc 3A
possess Lewis acidic nature at the zinc atoms, undergoing SE2′
type reaction with aldehydes through a six-membered cyclic
transition state to give 14a with high anti-selectivity.13,14 On
the other hand, allenic zincates without appreciable Lewis acidity
coupled with aldehydes both via SE2 and SE2′ pathways through
linear transition states.
Reactions were examined for various combinations of pro-
pargylic substrates, organozincates, and aldehydes under similar
conditions (Table 4). The reaction of aliphatic aldehydes
exhibited high anti-selectivity (>94:6). Of these reactions,
higher selectivities were observed in the reaction of bulky
aldehydes (entries 1-5). Stereoselectivity was constantly high
irrespective of the steric as well as the electronic nature of the
substituent R3 in allenic zinc reagents (entries 12-16). The
reaction with benzaldehyde exhibited a notably low level of
stereoselectivity (entry 5). A similar anomaly of benzaldehyde
has been observed elsewhere.13a,19 High synthetic utility of the
present one-pot reactions is also exemplified in application to
The identity of the major product as the anti isomer was
established for 14j by chemical correlation with the previously
reported acetal derivative 1821 (Scheme 4). In 1H NMR analysis,
(20) It was reported that the reaction of allenic allanates with aldehydes
gave homopropargylic alcohols regioselectively but with low diastereose-
lectivity; Zweifel, G.; Hahn, G. J. Org. Chem. 1984, 49, 4565.
(21) Harada, T.; Matsuda, Y.; Uchimura, J.; Oku, A. J. Chem. Soc., Chem.
Commun. 1989, 1429.
(19) (a) Favre, E.; Gaudemar, M. J. Organomet. Chem. 1975, 92, 17.

11382 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
Table 4. Preparation of Homopropargylic Alcohols 14 by the Reactions of Allenic Zinc Reagents 3 with Aldehydesa
a Unless otherwise noted, allenic zinc reagents were prepared by using 2.0 equiv of zincates under conditions A in Table 1 and allowed to
react with aldehydes (1.5 equiv) at the tempratures from -85 to 0 °C after treatment with ZnCl2 (3.0 equiv). b Unless otherwise noted, the ratios
1
were determined by GC analysis (30 m OV-1 capillary column). c The ratio was determined by H NMR anlysis. d 3.0 Equiv of the zincate were
used. The resulting allenic zinc was used after treatment with 5.0 equiv of ZnCl2. e Allenic zinc reagent 3m was prepared under conditions B in
Table 1.
18 showed a typical axial-axial coupling between Ha and Hb
(Jab ) 10.2 Hz).
chloride in a nonregioselective manner affording a 1:1 mixture
of alkynone 19f and allenyl ketone 20f (entry 8).
Coupling Reactions of Allenic Zinc Species 3 with Other
Electrophiles. Allenic zinc reagents 3 also underwent coupling
reaction with other electrophiles such as acyl chlorides, chlo-
rosilanes, iodine, and NCS affording the corresponding prop-
argylic derivatives regioselectively (Table 5).
Alkynones 19a-d were prone to isomerization to allenyl
ketones 23a-d under non-neutral conditions. Precautions were
required in their isolation by silica gel column chromatography.
Treatment of alkynones 19a-d with triethylamine in methanol
yielded quantitatively ketones 23a-d (eq 10), which has
previously been used as intermediates for the synthesis of 2,3,5-
trisubstituted furan derivatives.22
Treatment of disubstituted allenic zinc 3a, prepared from 1a
and Bu3ZnLi (2 equiv), with 1.5 equiv of acyl chlorides at -75
°C for 3 h gave regioselectively alkynones 19a-d with minor
formation of allenyl ketones 20a-d (entries 1-5). As in the
reaction with aldehydes, butyl addition to the acyl halide was
not detected. The higher level of the regioselectivity was
observed in the reaction of sterically demanding pivaloyl
chloride (entry 5). In the acylation, the addition of ZnCl2 (3
equiv) did not improve the regioselectivity (entry 4). For
ethoxycarbonylation of 3a, 3.0 equiv of ethyl chloroformate was
necessary to obtain the satisfactory yield of 19e (entries 6 and
7). Trisubstituted allenic zinc 3m, generated by the reaction
of chloride 1m with (Bu)3ZnLi (2.0 equiv), reacted with acetyl
(22) (a) Marshall, J. A.; Robinson, E. D. J. Org. Chem. 1990, 55, 3450.
(b) Marshall, J. A.; Wang, X.-j. J. Org. Chem. 1991, 56, 960. (c) Marshall,
J. A.; Wang, X.-j. J. Org. Chem. 1992, 57, 3387.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11383
Treatment of allenic zinc 3a with iodine (6 equiv) at -85 °C
gave 3-iodo-1-phenyl-4-nonyne (22a) in 81% yield together with
a small amount of 5-iodo-1-phenyl-3,4-nonadiene (23a) (entry
9). Chlorination of 3a with NCS also proceeded regioselectively
to give propargylic chloride 22b (entry 10), while, on the other
hand, attempted bromination either with Br2 or NBS resulted
in the formation of complex mixtures. Reaction of allenic zinc
3a with chlorotrimethylsilane and chorodimetylphenylsilane
afforded regioselectively propargylic silanes 24a and 24b,
respectively, in high yields (entries 11 and 12). The selectivity
was decreased when chloro(chloromethyl)dimethylsilane and
chlorotriethylsilane were used (entries 13 and 14). No coupling
reaction took place with tert-butylchlorodimethylsilane.
Preparation and Reaction of Silicon Containing Orga-
nozinc Reagents. In past few decades, advances have been
made in the use of organosilicon compounds in organic
synthesis.23 Of these, propargyl- and ethynylsilanes have been
established to be synthetic equivalents of allenic and acetylenic
anions, respectively. The intramolecular reactions of function-
alized propargyl- and ethynylsilanes has been often utilized for
the construction of polycyclic carbon frameworks.24 As de-
scribed in the previous section, propargyl silanes 24 were
obtained in high yields by the reaction of propargylic substrates
with triorganozincates followed by silylation of the resulting
allenic zinc reagents. R-(Trimethylsilylmethyl)allenic zincs 26
and R-silylallenic zincs 29 would be prepared by the three-
carbon homologation of (Me3SiCH2)3ZnLi and (R3Si)3ZnLi,
respectively. These silicon containing allenic zincs may serve
as versatile reagents for the synthesis of functionalized prop-
argylsilanes 28 and ethynylsilanes 31, respectively (Scheme 5).
For the preparation of R-(trimethylsilylmethyl)allenic zincs
26, we first examined the reaction of mesylate 1a with (Me3-
SiCH2)3ZnLi (eq 11). Although the reaction afforded silylallene
32a with minor formation of silylalkyne 33a, the low level of
deuterium incorporation in the products indicated the poor yields
of the desired zinc reagents 26a and 27a. The reaction of
chloride 1m afforded silylmethylallene 32b exclusively but again
with low deuterium incorporation (eq 12).
Scheme 5
section, when the deprotonation step is slower than the
subsequent 1,2-migration step, deprotonation of 1 by allenic
zincate 3 (ZnL ) Zn(R)2Li), formed reversibly, may well
compete with the reaction by the triorganozincate resulting in
the less efficient generation of allenic zinc reagents. The
problem was anticipated to be solved by using a substrate with
a less reactive leaving group which reduces the rate of 1,2-
migration.
Treatment of diphenylcarbamate 1d with (TMSCH2)3ZnLi at
-15 °C for 1 h followed by the addition of D2O lead to clean
generation of alkynylzincate 34 as demonstrated by 89%
deuterium incorporation in [1-2H]-1d obtained in 86% yield (eq
13). While either silylallene 32a or silylalkyne 33a was not
formed at this temperature, further treatment of the mixture at
rt for 2 h followed by the addition of D2O gave [2-2H]-32a
with 95% deuterium incorporation and [4-2H]-33a with 77%
deuterium incorporation in 51% and 30% yields, respectively.
The combined yield of an equilibrating mixture of allenic zinc
26a and propargylic zinc 27a is thus estimated to be 72%.
The basicity of (TMSCH2)3ZnLi is considered to be lower
than that of simple trialkylzincates because of the anion
stabilizing ability of the R-silicon atom.25 This may cause
retardation of the rate of the initial deprotonation step to form
the alkynylzincate intermediate. As discussed in the previous
Having established the method for the preparation of R-(tri-
methylsilylmethyl)allenic zincs 26, we then examined their
reactions with electrophiles (Scheme 6). Although the result
of D2O-quench experiment indicated that considerable amount
of the reagents existed as propargylic zinc 27 under these
conditions, the reactions gave propargylic adducts 35-38
regioselectively. Thus, iodides 35a,b, disilylalkynes 36a,b, and
alkynones 39a,b were obtained exclusively in the reaction of
(23) (a) Fleming, I. In ComprehensiVe Organic Synthesis; Heathcock,
C. H., Ed.; Pergamon Press: Oxford, 1991; Vol. 2, p 563. (b) Schinzer, D.
Synthesis 1988, 263.
(24) Mulzer, J.; Altenbach, H.-J.; Braun, M.; Krohn, K.; Ressig, H.-U.
Organic Synthesis Highlights; VCH Publishers: Weinheim, 1991; p 131.
(25) Bassindale, A. R.; Taylor, P. G. In The Chemistry of Organosilicon
Compounds; Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1989; p
809.

11384 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
Table 5. Coupling Reactions of Allenic Zinc Reagents 3a,m with Electrophilesa
a Allenic zinc reagents 3a and 3m were prepared by using 2 equiv of Bu3ZnLi under conditions A and B in Table 1, respectively. b Conditions
for the reaction with electrophiles; D (-75 °C for 3 h), E (at -85 to 0 °C over 1 h), and F (at -85 °C to rt over 2 h). c The allenic zinc reagent
was used after treatment with ZnCl2 (3 equiv).
Scheme 6
The reaction of mixed zincate (PhMe2Si)2BuZnLi gave silylation
products 42a and 43a without formation of the butylation
product 5a. The yield of 42a did not drop significantly even
when 1.2 equiv of the mixed zincate were used. Previously,
Fleming et al. have reported the preparation of silylallenes by
the reaction of propargylic substrates with silylcuprates [(R3-
Si)2CuLi].26 As illustrated in entries 6 and 7, the reaction with
the silylzincates is also applicable to other substrates and,
therefore, serves as an alternative method for the preparation
of silylallenes.
The relatively less basic nature of arylsilylmetals27 may
rationalize the absence of deuterium in the products. Alterna-
tively, silylallene 42 would be produced through a direct SN2′-
type displacement by the silylzincates (eq 5) although such
mechanism alone can not explain the formation of silylalkyne
43 as a minor product.28 Irrespective to these mechanistic
possibilities, it seemed that rapid generation of the intermediate
alkynylzincate 41 is crucial for the successful generation of
allenic zinc reagents 29. It is well known that the rate of
halogen/metal exchange is generally very fast even at low
temperatures. Previously, we showed that gem-dibromo com-
pounds undergo bromine/zinc exchange reaction rapidly with
organozincates at low temperatures to give the corresponding
zincate carbenoids.3-5,29 More recently, the preparation of
arylzincates by iodine/zinc exchange reaction of iodoarenes with
organozincates have been reported.30 These results prompted
I2, TMSCl, and pivaloyl chloride, respectively. The reactions
of aldehydes proceeded stereoselectively as well to furnish anti-
alcohols 38a-c.
(26) (a) Fleming, I.; Terrett, N. K. J. Organomet. Chem. 1984, 264, 99.
(b) Fleming, I.; Takai, K.; Thomas, A. P. J. Chem. Soc., Perkin Trans. 1
1987, 2269.
(27) Lambert, J. B.; Scultz, W. J., Jr. In The Chemistry of Organosilicon
Compounds; Patai, S., Rappoport, Z., Eds.; Wiley: New York, 1989; p
1007.
(28) Treatment of PhMe2SiH with Bu3ZnLi in THF at rt followed by
addition of D2O resulted in the recovery of PhMe2SiH without deuterium
incorporation. Judging from the observation, it is less likely that silylallene
42 is formed through a mechanism involving a metathesis of the intermediate
allenic zinc species and PhMe2SiH that would be produced initially in the
reaction of the silylzincates with the terminal alkyne.
(29) Harada, T.; Katsuhira, T.; Hattori, K.; Oku, A. Tetrahedron 1994,
50, 7987.
For the preparation of R-silylallenic zinc 29, reactions were
examined by using silylzincates (PhMe2Si)3ZnLi and (PhMe2-
Si)2BuZnLi, which were prepared by the reaction of ZnCl2 with
PhMe2SiLi (3.0 equiv) and by the reaction of ZnCl2 with PhMe2-
SiLi (2.0 equiv) and BuLi (1.0 equiv), respectively (Table 6).12a
Although the reactions of mesylate 1a and phosphate 1c lead
to the regioselective and high-yield formation of silylallene 42a
with minor formation of silylalkyne 43a (entries 1-4), no
deuterium was found in the products in the D2O-quench
experiments even when carbamate 1d was employed (entry 5).
(30) Kondo, Y.; Takezawa, N.; Yamazaki, C.; Sakamoto, T. J. Org.
Chem. 1994 59, 4717.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11385
Table 6. Reaction of Propargylic Derivative 1 with Silylzincatesa
a Unless otherwise noted reactions were performed by using 2.0 equiv of silylzincates under conditions A in Table 1. b 1.2 Equiv of the silylzincate
was used.
Table 7. Reaction of Bromopropargyl Mesylate 40a with
us to examine the reaction of bromopropargyl mesylates 40 and
silylzincates (eq 15).
Silylzincatesa
yield deuterium
equiv products (%) content (%)
entry
1
silylzincate
(PhMe2Si)3ZnLi
2.0
1.2
1.2
43a
42a
43a
42a
43a
42a
46
74
16
75
9
34
4
27
37
41
93
91
93
82
88
78
2
3
(PhMe2Si)3ZnLi
(PhMe2Si)2(Bu)ZnLi
4
Bu3ZnLi
1.2
5a
48
>95
a Reactions were performed at -85 °C in THF for 15 min and
quenched by the addition of CD3OD.
Scheme 7
The requisite bromopropargyl mesylates 40a-c were prepared
readily by the reaction of dianion of the corresponding prop-
argylic alcohols with Br2 and subsequent mesylation of the
resulting bromoalcohols 39a-c (eq 14). The reaction of 40a
with (PhMe2Si)3ZnLi (2 equiv) completed within 15 min at -85
°C. Treatment of the reaction mixture with CD3OD at this
temperature afforded silylalkyne [3-2H]-43a and silylallene
[1-2H]-42a with high deuterium incorporation in 74% and 16%
yield, respectively (Table 7, entry 1). The combined yield of
propargylic zinc 30a and allenic zinc 29a which are in
equilibrium under these conditions is estimated to be 82%. The
efficient preparation of the organozinc reagents (77% yield) was
also obtained even when 1.2 equiv of the silylzincate was used
(entry 2). The use of mixed zincate (PhMe2Si)2BuZnLi resulted
in the less efficient generation of the 30a and 29a (entry 3).
Disilylialkyne 46 (27%) (Scheme 7) and butylation product 5a
(17%) were produced as byproducts in this reaction. We, there-
fore, chose the reaction using a 1.2 equiv of (PhMe2Si)3ZnLi
(entry 2) as an optimal method and the silicon containing
organozinc species 30 and 29 prepared by this method was used
in the reaction with electrophiles.
As demonstrated in Scheme 7, silylzinc reagents 30 and 29
generated under these conditions underwent regioselective
coupling reaction with electrophiles to give the corresponding
functionalized silylalkynes 44-46.31 Although the result of
CD3OD-quench experiment showed that propargylic zinc 30 is

11386 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
a predominant species in the equilibrium,32 the coupling
reactions most probably took place from a minor but more
reactive allenic zincs judging from regioselective formation of
propargylic adducts as well as high anti-selectivity in the
reaction with aldehydes. The results also indicates relatively
fast rate of equilibration between 29 and 30.
It should be noted that, upon warming up the reaction mixture
of 40a and (PhMe2Si)3ZnLi silylzinc reagents to rt without
addition of PhMe2SiCl, disilylalkyne 46 was obtained in 31%.
The result supports the formation of PhMe2SiBr by the bromine/
zinc exchange with the silylzincate. The sililylation by PhMe2-
SiBr was almost negligible at -85 °C judging from a minor
formation of 46 (<5%) in CD3OD-quench experiment (Table
7, entries 1 and 2).33 The reaction of 40a with Bu3ZnLi (1.2
equiv) gave not only allene [5-2H]-5a with high deuterium
incorporation (37%) but also bromoallene PhCH2CH2CHdCdC-
(Br)Bu (48) (41%), which might be formed by bromine/zinc
exchange reaction of unreacted substrate 40a with zinc reagents
29a and/or 30a (entry 5). The result, therefore, suggests that
silylzincates are more reactive in bromine/zinc exchange reaction
than trialkylzincates.
In summary, we have developed a general method for the
three-carbon homologation of triorganozincates by the reaction
of propargylic substrates 1 (Scheme 2). With the combination
of the propargylic substrates and organozincates, a wide range
of allenic zinc reagents 3, including the silyl derivatives 26 and
29, are available. The allenic zinc reagents underwent coupling
reaction with a variety of electrophiles regioselectively at the γ
positions to give the corresponding propargylic derivatives 4,
providing an efficient one-pot method for introduction of a
nucleophile (R1) and an electrophile (El) to the propargylic
substrates at the 1,3-positions. Of these, the reaction with
aldehydes proceeded with high stereoselectivity as well to give
anti-homopropargyl alcohols.
zincates Et2(R)ZnLi were prepared as follows: To a solution of Et2Zn
(2 mmol, 1 M in hexane) in THF (6 mL) at 0 °C was added RM (2
mmol), and the mixture was stirred for 15 min at this temperature.
General Procedure for the Preparation of Allenic Zincs 3a-m
(D2O-Quench Experiment, Table 2). To a solution of triorganozin-
cates (1.4 mmol) in THF at -85 °C was added a solution of propargylic
derivative 1 (0.7 mmol) in THF (1 mL) and the mixture was stirred
for 15 min. The cooling bath was exchanged to the one at 0 °C and
the mixture was stirred further for 15 min. After addition of D2O (ca.
0.5 mL), the mixture was poured into 1 N HCl and extracted three
times with ether. The combined organic layers were washed with
NaHCO3 (5%), dried, and concentrated. The residue was purified by
flash chromatography (pentane or hexane) to afford deuterio allenes
5a-m. The deuterium contents were analyzed by 1H NMR. Spectral
data of non-deuterio allenes 5a,b, prepared separately by quenching 3
with H2O, are as follows.
1-Phenyl-3,4-nonadiene (5a): 1H-NMR δ 0.90 (3H, m), 1.27-1.42
(4H, m), 1.96 (2H, m), 2.31 (2H, m), 2.73 (2H, br t, J ) ca. 8 Hz),
5.05-5.18 (2H, m), 7.16-7.32 (5H, m); 13C-NMR δ 203.9, 141.9,
128.5, 128.2, 125.8, 91.5, 90.2, 35.5, 31.3, 30.7, 28.6, 22.2, 13.9; IR
(liquid film) 1960, 1600, 1495, 1450, 870, 740, 695 cm-1; MS, m/z
(relative intensity) 200 (M+,4), 157 (20), 144 (32), 129 (50), 91 (100);
HRMS calcd for C15H20; 200.1566, found; 200.1562. Anal. Calcd for
C15H20: C, 89.94; H, 10.06. Found C, 90.18; H, 10.30.
1
5-Phenyl-2,3-hexadiene (5b): H-NMR δ 1.62 (3H, dd, J ) 3.5
and 6.7 Hz), 2.27-2.36 (2H, m), 2.74 (2H, br t, J ) ca. 8 Hz), 5.02-
5.16 (2H, m), 7.17-7.33 (5H, m); IR (liquid film) 1965, 1605, 1495,
1450, 870, 745, 700 cm-1; MS, m/z (relative intensity) 158 (M+, 7),
143 (36), 129 (81), 91 (100); HRMS calcd for C12H14; 158.1096, found;
158.1092. Anal. Calcd for C12H14: C, 91.08; H, 8.92. Found C, 90.95;
H, 9.04.
General Procedure for the Preparation of Homopropargyl
Alcohols 14a-x. Allenic zinc intermediate 3 was prepared from
propargylic mesylate 1 (1.0 mmol) by a procedure described above.
To a solution of the allenic zinc 3 at -85 °C was added a solution of
ZnCl2 (1.0 M in THF) (3.0 mL, 3.0 mmol) over 15 min by using a
syringe-pump. The mixture was stirred for additional 1 h at the same
temperature. An aldehyde (1.5 mmol) was then added, and the mixture
was allowed to warm to 0 °C during 2 h. The mixture was poured
into 1 N HCl (20 mL) and extracted three times with ether. The
combined organic layers were washed with 5% NaHCO3, dried, and
concentrated in vacuo. Purification of the residue by flash chroma-
tography (5-20% ethyl acetate in hexane or 10-20% ether in pentane)
afforded homopropargyl alcohols 14a-x.
(3R*,4S*)-4-Octyl-1-phenyl-5-decyn-3-ol (anti-14a): bp 170-180
°C/0.15 mmHg (Kugelrohr); 1H-NMR δ 0.88 (3H, t, J ) 6.8 Hz), 0.91
(3H, t, J ) 7.2 Hz), 1.22-1.54 (18H, m), 1.70-1.93 (3H, m, including
OH), 2.19 (2H, dt, J ) 2.1 and 6.8 Hz), 2.39 (1H, m), 2.68 (1H, td, J
) 8.2 and 14.0 Hz), 2.82 (1H, ddd, J ) 6.7, 8.6, and 14.0 Hz), 3.44
(1H, br q), 7.15-7.31 (5H, m); 13C-NMR δ 142.2, 128.4, 128.3, 125.7,
84.7, 79.0, 72.6, 39.4, 37.5, 32.14, 32.12, 31.9, 31.1, 29.5, 29.4, 29.2,
27.6, 22.7, 21.9, 18.4, 14.1, 13.6; IR (liquid film) 3550 (br), 3430 (br),
1465, 1450, 745, 725, 695 cm-1; MS (CI), m/z (relative intensity) 343
(MH+, 2), 325 (11), 238 (9), 110 (100), 91 (88); HRMS (CI) calcd for
C24H39O (MH+); 343.3003, found; 343.3004. Anal. Calcd for
C24H38O: C, 84.15; H, 11.18. Found C, 84.12; H, 11.03.
(3S*,4S*)-4-Octyl-1-phenyl-5-decyn-3-ol (syn-14a): 1H-NMR δ
0.88 (3H, t, J ) 7.0 Hz), 0.91 (3H, t, J ) 7.1 Hz), 1.20-1.54 (18H,
m), 1.74 (1H (OH), br d, J ) 6.7 Hz), 1.76-1.97 (2H, m), 2.18 (2H,
dt, J ) 2.2 and 6.8 Hz), 2.50 (1H, m), 2.67 (1H, ddd, J ) 7.0, 9.6, and
13.7 Hz), 2.90 (1H, ddd, J ) 5.4, 9.8, and 13.7 Hz), 3.55 (1H, m),
7.16-7.32 (5H, m); 13C-NMR δ 142.3, 128.5, 128.3, 125.7, 83.9, 80.0,
73.0, 39.4, 35.4, 32.2, 31.9, 31.2, 30.5, 29.5, 29.4, 29.3, 27.6, 22.7,
21.9, 18.4, 14.1, 13.6; IR (liquid film) 3550 (sh), 3390 (br), 1465, 1455,
750, 725, 700 cm-1; MS (CI), m/z (relative intensity) 343 (MH+, 1.2),
325 (7), 238 (10), 138 (76), 110 (94), 91 (100); HRMS (CI) calcd for
C24H39O (MH+); 343.3003, found; 343.3006.
(3R*,4S*)-4-Octyl-5-decyn-3-ol (anti-14b): bp 80-85 °C/0.15
mmHg (Kugelrohr); 1H-NMR δ 0.87 (3H, t, J ) 7.0 Hz), 0.90 (3H, t,
J ) 7.3 Hz), 0.95 (3H, t, J ) 7.4 Hz), 1.20-1.62 (20H, m), 1.73 (1H
(OH), br d, J ) 5 Hz), 2.18 (2H, dt, J ) 2.2 and 6.9 Hz), 2.38 (1H,
m), 3.32 (1H, br s); 13C-NMR δ 84.5, 79.2, 74.7, 38.8, 32.2, 31.9, 31.2,
Experimental Section
General Methods. Unless otherwise noted 1H- and 13C-NMR
spectra were recorded at 300 MHz and 75.6 MHz, respectively, in
CDCl3. All commercially available reagents were used without further
purification unless otherwise noted. Triethylamine, N,N-diisopropyl-
ethylamine, chlorotrimethylsilane, and dichloromethane were distilled
from CaH2. THF was distilled from sodium benzophenone ketyl. All
reactions were performed under argon. Unless otherwise noted, organic
extracts were dried over MgSO4. Flash chromatography was conducted
on silica gel (Wakogel C-300). For the preparation of starting materials
1a-q and 40a-c, see Supporting Information.
General Procedure for the Preparation of Triorganozincates
R3ZnM (M ) Li or MgCl). To a solution of ZnCl2 (191 mg, 1.4
mmol) in THF (4.2 mL) at 0 °C was added a solution of RM (4.2
mmol) (BuLi; 1.6 M in hexane; BuMgBr; 1 M in THF, MeLi; 1.4 M
in ether, s-BuLi, 1.3 M in cyclohexane; t-BuLi; 1.5 M in pentane, PhLi;
1 M in cyclohexane-ether, TMSCH2Li; 1 M in pentane, PhMe2SiLi;34
1 M in THF). The mixture was stirred for 15 min at 0 °C. Mixed
(31) The byproduct formation of isomeric allenic alcohols was observed
in the reaction of silylzinc reagents 30a and 29a: the reactions with
2-methylpropanal and 6,6-dimethoxyhexanal gave 7-methyl-1-phenyl-5-
(dimethylphenylsilyl)-3,4-octadien-6-ol (47a) (14%) and 11,11-dimethoxy-
1-phenyl-5-(dimethylphenylsilyl)-3,4-undecadien-6-ol (47b) (11%), respec-
tively.
(32) When the reaction of 40a and (PhMe2Si)3ZnLi (1.2 equiv) was
quenched with CD3OD after treatment with ZnCl2 (1.6 equiv), silylalkyne
[3-2H]-43a (89%-d) and silylallene [1-2H]-42a (58%-d) were obtained in
77% and 7.8% yield, respectively.
(33) On the other hand, nonnegligible amount of 46 (27%) was produced
in the reaction of (PhMe2Si)2BuZnLi. The difference in reactivity might be
derived from the differences of ligands.
(34) Gilman, H.; Lichtenwalter, G. D. J. Am. Chem. Soc. 1958, 80, 607.
(35) Fleming, I.; Newton, T. W.; Roessler, F. J. Chem. Soc., Perkin Trans.
1 1981, 2527.
(36) Jun, C.-H.; Brabtree, R. H. J. Organomet. Chem. 1993, 447, 177.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11387
29.51, 29.44, 29.3, 28.5, 27.6, 22.7, 21.9, 18.4, 14.1, 13.6, 10.2; IR
(liquid film) 3570 (br), 3425 (br), 1465, 1460, 1105, 975 cm-1; MS
(CI), m/z (relative intensity) 267 (MH+, 3), 249 (9), 237 (3), 166 (7),
137 (10), 123 (13), 110 (100); HRMS (CI) calcd for C18H35O (MH+);
267.2690, found; 267.2689. Anal. Calcd for C18H34O: C, 81.13; H,
12.86. Found C, 80.99; H, 12.86.
(3S*,4S*)-4-Octyl-5-decyn-3-ol (syn-14b): 1H-NMR δ 0.88 (3H,
t, J ) 7.0 Hz), 0.91 (3H, t, J ) 7.1 Hz), 0.99 (3H, t, J ) 7.4 Hz),
1.20-1.69 (21H, m, including OH (br d, J ) 6.4 Hz) at 1.65), 2.18
(2H, dt, J ) 2.2 and 6.9 Hz), 2.47 (1H, m), 3.44 (1H, m); 13C-NMR δ
83.7, 80.3, 75.2, 39.0, 31.9, 31.2, 30.3, 29.53, 29.50, 29.3, 27.6, 26.5,
22.7, 21.9, 18.4, 14.1, 13.6, 10.3; IR (liquid film) 3360 (br), 1465,
1460, 1110, 975 cm-1; MS (CI), m/z (relative intensity) 267 (MH+, 5),
265 (5), 249 (16), 123 (23), 110 (100); HRMS (CI) calcd for C18H35O
(MH+); 267.2690, found; 267.2682.
General Procedure for Acylation Allenic Zinc 3a. Allenic zinc
3a was prepared from propargylic mesylate 1a (167 mg, 0.7 mmol) by
a procedure described previously. To a solution of 3a at -75 °C was
added an acylchloride (1.05 mmol) or ethyl chloroformate (2.1 mmol),
and the resulting mixture was then stirred at -75 °C temperature for
3 h. The mixture was poured into 1 N HCl (20 mL) and extracted
three times with ethyl acetate (15 mL). The combined organic extracts
were washed with 5% NaHCO3, dried, and concentrated in vacuo.
Purification of the residue by flash chromatography using cooled (ca.
5 °C) 5-10% ether in hexane as an eluent afforded a mixture of the
propargylic ketone 19 and the allenic ketone 20. The spectral data of
the propargylic products 19a,f and the allenic ketone 20f are as follows.
3-(2-Phenylethyl)-4-nonyn-2-one (19a): bp 120-130 °C/0.05 mmHg
(Kugelrohr); 1H-NMR δ 0.93 (3H, t, J ) 7.2 Hz), 1.37-1.57 (4H, m),
1.85-2.08 (2H, m), 2.24 (2H, dt, J ) 2.4 and 6.9 Hz), 2.27 (3H, s),
2.68 (1H, ddd, J ) 7.4, 8.8, and 13.7 Hz), 2.80 (1H, ddd, J ) 5.7, 9.0,
and 13.7 Hz), 3.14 (1H, tdd, J ) 2.4, 5.2, and 8.8 Hz), 7.15-7.31
(5H, m) [a minor product 20a resonated at 2.10 (3H, s) and 5.57 (1H,
tt, J ) 2.5 and 7.0 Hz)]; 13C-NMR δ 205.9, 141.2, 128.5, 128.4, 126.0,
85.7, 76.8, 45.0, 33.0, 32.8, 30.8, 27.6, 21.9, 18.4, 13.5; IR (liquid
film) 1720, 1495, 1450, 1355, 750, 695 cm-1; MS, m/z (relative
intensity) 242 (M+, 4), 241 (9), 199 (3), 185 (6), 138 (23), 91 (74), 43
(100); HRMS calcd for C17H22O; 242.1671, found; 242.1666. Anal.
Calcd for C17H22O: C, 84.25; H, 9.15. Found C, 84.07; H, 9.05.
1-Acetyl-1-(1-hexynyl)cyclohexane (19f): bp 80-90 °C/0.07 mmHg
(Kugelrohr); 1H-NMR δ 0.90 (3H, t, J ) 7.2 Hz), 1.15 (1H, m), 1.34-
1.80 (13H, m), 2.21 (2H, t, J ) 6.8 Hz), 2.29 (3H, s); 13C-NMR δ
209.0, 85.9, 80.8, 49.7, 33.8, 31.0, 25.7, 25.6, 22.4, 21.9, 18.5, 13.6;
IR (liquid film) 2230 (m), 1715, 1450, 1350, 1210, 1170 cm-1; MS,
m/z (relative intensity) 206 (M+, 2), 191 (4), 177 (4), 163 (46), 121
(37), 93 (46), 79 (65), 67 (87), 43 (100); HRMS calcd for C14H22O;
206.1672, found; 206.1684. Anal. Calcd for C14H22O: C, 81.50; H,
10.75. Found C, 81.24; H, 10.67.
(21), 199 (6), 185 (10), 151 (10), 91 (51), 43 (100); HRMS calcd for
C17H22O; 242.1672, found; 242.1664. Anal. Calcd for C17H22O: C,
84.25; H, 9.15. Found C, 84.13; H, 9.28.
6-(2-Phenylethyl)-6,7-dodecadien-5-one (23b): 1H-NMR δ 0.89
(3H, t, J ) 7.3 Hz), 0.90 (3H, t, J ) 7.0 Hz), 1.23-1.42 (6H, m),
1.49-1.59 (2H, m), 1.99-2.07 (2H, m), 2.39-2.62 (4H, m, including
dtd (1H, J ) 2.5, 8.0, and 14.6 Hz) at 2.45 and br t (2H) at 2.59), 2.70
(2H, br t), 5.48 (1H, tt, J ) 2.5 and 7.0 Hz), 7.13-7.29 (5H, m); 13C-
NMR δ 211.8, 202.0, 141.7, 128.5, 128.2, 125.7, 108.1, 95.7, 38.9,
34.1, 31.2, 28.5, 27.9, 27.3, 22.4, 22.2, 13.85, 13.79; IR (liquid film)
1945, 1675, 1455, 745, 695 cm-1; MS, m/z (relative intensity) 284 (M+,
14), 283 (22), 227 (11), 193 (6), 91 (54), 85 (73), 57 (100); HRMS
calcd for C20H28O; 284.2141, found; 284.2143.
3-Iodo-1-phenyl-4-nonyne (22a). To a solution of allenic zinc 3a,
prepared from 1a (0.7 mmol) as described previously, at -85 °C, was
added a solution of I2 (1.07 g, 4.2 mmol) in THF (1 mL) over a period
of 15 min by using a syringe-pump. The mixture was allowed to warm
to 0 °C over 1 h, then poured into 1 N HCl (20 mL), and extracted
three times with ether (15 mL). The combined organic extracts were
washed successively with saturated NaHSO3 and 5% NaHCO3, dried,
and concentrated in vacuo. Purification of the residue by flash
chromatography (hexane) gave 185 mg (81%) of 22a and 13.7 mg (6%)
of 5-iodo-1-phenyl-3,4-nonadiene (23a). 22a: bp 120-140 °C/0.05
1
mmHg (Kugelrohr); H-NMR δ 0.92 (3H, t, J ) 7.2 Hz), 1.36-1.56
(4H, m), 2.13-2.33 (4H, m), 2.70-2.88 (2H, m), 4.52 (1H, tt, J ) 2.3
and 6.8 Hz), 7.18-7.33 (5H, m); 13C-NMR δ 140.2, 128.6, 128.5, 126.2,
88.2, 81.5, 43.2, 35.3, 30.5, 21.9, 18.8, 13.6, 11.8; IR (liquid film)
2225, 1495, 1450, 745, 700 cm-1; MS, m/z (relative intensity) 199 (M+
- I, 5), 143 (18), 129 (9), 117 (11), 91 (100). Anal. Calcd for
C15H19I: C, 55.23; H, 5.87. Found C, 55.39; H, 5.90. 23a: 1H-NMR
δ 0.90 (3H, br t, J ) ca. 7 Hz), 1.25-1.44 (4H, m), 2.25-2.32 (2H,
m), 2.32-2.49 (2H, m), 2.76 (2H, br t, J ) ca. 7.6 Hz), 5.04 (1H, tt,
J ) 2.9 and 6.5 Hz), 7.17-7.33 (5H, m); 13C-NMR δ 202.3, 141.2,
128.42, 128.36, 126.0, 93.4, 63.9, 40.6, 34.6, 31.2, 29.9, 21.4, 13.8;
IR (liquid film) 1950, 1600, 1495, 1450, 1105, 740, 695 cm-1; MS,
m/z (relative intensity) 199 (M+ - I, 4), 143 (21), 129 (12), 117 (12),
91 (100).
3-Chloro-1-phenyl-4-nonyne (22b). To a stirred solution of allenic
zinc 3a, prepared from 1a (0.7 mmol) as described previously, at -85
°C, was added N-chlorosuccinimide (0.56 g, 4.2 mmol) in one portion.
The resulting suspension was then allowed to warm to 0 °C over 1 h.
The mixture was poured into 1 N HCl (20 mL), and it was extracted
three times with ether (15 mL). The combined extracts were washed
with 5% NaHCO3, dried, and concentrated in vacuo. Purification of
the residue by flash chromatography (hexane) gave 135 mg (82%) of
22b and 6.6 mg (4%) of 5-chloro-1-phenyl-3,4-nonadiene (23b). 22b:
bp 105-115 °C/0.06 mmHg (Kugelrohr); 1H-NMR δ 0.92 (3H, t, J )
7.2 Hz), 1.35-1.56 (4H, m), 2.17-2.28 (4H, m), 2.84 (2H, br t, J )
ca. 7 Hz), 4.52 (1H, tt, J ) 2.1 and 6.7 Hz), 7.17-7.33 (5H, m); 13C-
NMR δ 140.4, 128.51, 128.48, 126.2, 87.7, 78.3, 48.8, 41.1, 32.3, 30.5,
21.9, 18.5, 13.6; IR (liquid film) 2240, 1605, 1495, 1465, 1455, 1330,
3-(Cyclohexylidene)methyleneheptan-2-one (20f): bp 90-95 °C/
1
0.06 mmHg (Kugelrohr); H-NMR δ 0.87 (3H, m), 1.22-1.39 (4H,
m), 1.52-1.70 (6H, m), 2.10-2.15 (2H, m), 2.18-2.26 (7H, m,
including s (3H) at 2.22); 13C-NMR δ 206.9, 200.0, 107.6, 106.4, 30.6,
30.1, 27.1, 26.8, 26.2, 25.8, 22.1, 13.9; IR (liquid film) 1945, 1675,
1445, 1350, 1260, 1245, 1230, 1215 cm-1; MS, m/z (relative intensity)
206 (M+, 6), 191 (3), 177 (3), 164 (22), 163 (23), 121 (28), 93 (29),
79 (44), 67 (57), 43 (100); HRMS calcd for C14H22O; 206.1672, found;
206.1659. Anal. Calcd for C14H22O: C, 81.50; H, 10.75. Found C,
81.24; H, 10.99.
750, 700 cm-1; MS, m/z (relative intensity) 234 (M+, 0.3), 199 (M+
-
Cl, 9), 198 (6), 155 (26), 141 (22), 129 (22), 91 (100); HRMS calcd
for C15H19Cl; 234.1177, found; 234.1200. Anal. Calcd for C15H19Cl:
1
C, 76.74; H, 8.16. Found C, 76.89; H, 8.14. 23b: H-NMR δ 0.89
(3H, t, J ) 7.2 Hz), 1.24-1.47 (4H, m), 2.26 (2H, dt, J ) 2.9 and 7.2
Hz), 2.32-2.50 (2H, m), 2.75 (2H, m), 5.52 (1H, tt, J ) 2.9 and 6.4
Hz), 7.15-7.31 (5H, m); 13C-NMR δ 199.2, 141.2, 128.4, 128.3, 126.0,
106.2, 99.1, 36.1, 34.7, 30.9, 29.2, 21.7, 13.8; IR (liquid film) 1970,
745, 700 cm-1; MS, m/z (relative intensity) 234 (M+, 0.3), 199 (3),
178 (9), 155 (14), 91 (100); HRMS calcd for C15H19Cl; 234.1177, found;
234.1180.
General Procedure for the Transformation of Alkynones 19a-d
to Allenic Ketones 23a-d. To a solution of alkynone 19 (0.25 mmol)
in ethanol (2.0 mL) at rt was added Et3N (0.053 mL, 0.38 mmol), and
the mixture was stirred for 15 h at rt. Concentration of the mixture in
vacuo and purification of the residue by flash chromatography (5%
ether in hexane) gave allenic ketone 23. The spectral data of 23a,b
are as follows.
3-(2-Phenylethyl)-3,4-nonadien-2-one (23a): bp 120-130 °C/0.05
mmHg (Kugelrohr); 1H-NMR δ 0.90 (3H, m), 1.25-1.42 (4H, m),
2.00-2.07 (2H, m), 2.25 (3H, s), 2.39-2.58 (2H, m), 2.7 (2H, br t, J
) ca. 8 Hz), 5.50(1H, tt, J ) 2.6 and 7.0 Hz), 7.13-7.29 (5H, m);
13C-NMR δ 212.4, 199.2, 141.6, 128.5, 128.2, 125.8, 108.7, 95.7, 34.0,
31.1, 28.3, 27.8, 26.9, 22.2, 13.8; IR (liquid film) 1950, 1680, 1355,
1230, 750, 700 cm-1; MS, m/z (relative intensity) 242 (M+, 9), 241
General Procedure for the Silylation of Allenic Zinc 3a. To a
stirred THF solution of allenic zinc 3a, prepared from 1a (0.7 mmol),
at -85 °C was added a chlorotriorganosilane (1.5 mmol). The mixture
was then allowed to warm to 0 °C over 2 h. The mixture was poured
into 1 N HCl (20 mL) and extracted three times with ether (15 mL).
The combined extracts were washed with 5% NaHCO3, dried, and
concentrated in vacuo. Purification of the residue by flash chroma-
tography (1-6% ether in hexane) gave propargylic silane 24 and allenic
silane 25. The spectral data of 24a,b and 25a,b are as follows.

11388 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
1
1-Phenyl-3-trimethylsilyl-4-nonyne (24a): H-NMR δ 0.04 (9H,
was purified by flash chromatography (1-5% benzene in hexane) to
give allenes [2-2H]-32a (51%, 95%-d) and alkyne [4-2H]-33b (30%,
77%-d).
s), 0.92 (3H, t, J ) 7.1 Hz), 1.38-1.73 (7H, m), 2.22 (2H, dt, J ) 2.2
and 6.7 Hz), 2.65 (1H, ddd, J ) 7.4, 8.7, and 13.5 Hz), 2.98 (1H, ddd,
J ) 5.3, 8.2, and 13.5 Hz), 7.14-7.31 (5H, m); 13C-NMR δ 142.5,
128.6, 128.2, 125.6, 81.2, 81.3, 35.8, 31.7, 31.6, 21.9, 19.4, 18.7, 13.6,
-3.2; IR (liquid film) 2220 (m), 1250, 865, 840, 745, 695 cm-1; MS,
m/z (relative intensity) 257 (M+ - CH3, 0.1), 198 (5), 91 (16), 73 (100).
Anal. Calcd for C18H28Si: C, 79.34; H, 10.36. Found C, 79.23; H,
10.24.
1-Phenyl-5-trimethylsilyl-3,4-nonadiene (25a): 1H-NMR δ 0.07
(9H, s), 0.89 (3H, t, J ) 7.1 Hz), 1.25-1.43 (4H, m), 1.91 (2H, m),
2.27 (2H, m), 2.69 (2H, m), 4.84 (1H, tt, J ) 3.0 and 6.5 Hz), 7.14-
7.31 (5H, m); 13C-NMR δ 205.2, 142.2, 128.5, 128.2, 125.7, 96.9, 84.9,
36.2, 31.3, 30.5, 29.1, 22.4, 14.0, -1.4; IR (liquid film) 1935, 1245,
835, 745, 695 cm-1; MS, m/z (relative intensity) 257 (M+ - CH3, 0.1),
198 (7), 91 (11), 73 (100).
4-Iodo-1-trimethylsilyl-6-phenyl-2-hexyne (35a). The reaction of
allenic zinc 26a with iodine (6 equiv) was carried out by a procedure
similar to that described in the preparation of 22a. Purification of the
crude products by flash chromatography (hexane) gave 35a (65%): 1H-
NMR δ 0.14 (9H, s), 1.53 (2H, d, J ) 2.7 Hz), 2.23 (2H, m), 2.81
(2H, m), 4.59 (1H, tt, J ) 2.7 and 6.8 Hz), 7.2-7.3 (5H, m); IR (liquid
film) 2220, 1250, 750, 700 cm-1; MS, m/z (relative intensity) 229 (M+
- I, 5), 213 (11), 155 (10), 91 (71), 73 (100); HRMS calcd for C15H21-
Si (M+ - I); 229.1413, found; 229.1415.
4-Iodo-9,9-dimethoxy-1-trimethylsilyl-2-nonyne (35b). The reac-
tion of allenic zinc 26 (R ) (MeO)2CH(CH2)4), prepared by the reaction
of carbamate 1p with (TMSCH2)3ZnLi, with iodine (6 equiv) was
carried out by a procedure similar to that described in the preparation
of 22a. Purification of the crude products by flash chromatography
(2% ethyl acetate in hexane) gave 35b (51%): 1H-NMR δ 0.11 (9H,
s), 1.3-1.7 (8H, m, including d (J ) 2.7 Hz, 2H) at 1.49), 1.92 (2H,
m), 4.36 (1H, t, J ) 5.7 Hz), 4.63 (1H, m); IR (liquid film) 2220,
1-Phenyl-3-(dimethylphenylsilyl)-4-nonyne (24b): bp 150-160 °C/
1.9 mmHg (Kugelrohr); 1H-NMR δ 0.340 (3H, s), 0.348 (3H, s), 0.92
(3H, t, J ) 7.1 Hz), 1.36-1.56 (4H, m), 1.58-1.70 (2H, m), 1.81 (1H,
m), 2.22 (2H, dt, J ) 2.5 and 6.8 Hz), 2.61 (1H, td, J ) 8.4 and 13.5
Hz), 2.94 (1H, ddd, J ) 6.0, 7.5, and 13.5 Hz), 7.12-7.39 (8H, m),
7.51-7.55 (2H, m); 13C-NMR δ 142.3, 137.2, 134.0, 129.1, 128.6,
128.2, 127.6, 125.6, 81.9, 80.9, 35.6, 31.54, 31.45, 21.9, 19.0, 18.7,
13.7, -4.3, -5.1; IR (liquid film) 2220 (m), 1245, 1110, 830, 815,
775, 745, 730, 695 cm-1. Anal. Calcd for C23H30Si: C, 82.57; H,
9.04. Found C, 82.40; H, 9.09.
1-Phenyl-5-(dimethylphenylsilyl)-3,4-nonadiene (25b): 1H-NMR
δ 0.33 (6H, s), 0.82 (3H, t, J ) 7.1 Hz), 1.18-1.37 (4H, m), 1.87 (2H,
br dt, J ) ca. 3.0 and 7.3 Hz), 2.27 (2H, br td, J ) ca. 6.5 and 8.9
Hz), 2.65 (2H, m), 4.88 (1H, tt, J ) 3.2 and 6.6 Hz), 7.14-7.37 (8H,
m), 7.49-7.55 (2H, m); 13C-NMR δ 206.4, 142.1, 138.5, 133.8, 128.9,
128.4, 128.2, 127.7, 125.7, 95.6, 85.6, 36.1, 31.2, 30.5, 29.2, 22.3, 13.9,
-2.85, -2.92; IR (liquid film) 1930, 1250, 1110, 830, 810, 775, 730,
1250, 1130, 850 cm-1; MS(CI), m/z (relative intensity) 351 (MH+
-
MeOH, <1), 223 (14), 119 (86), 73 (100); HRMS calcd for C13H24-
IOSi (MH+ - MeOH); 351.0643, found; 351.0651.
1,4-Bis(trimethylsilyl)-6-phenyl-2-hexyne (36a). The reaction of
allenic zinc 26a with chlorotrimethylsilane (1.5 equiv) was carried out
by a procedure similar to that described in a general procedure for the
silylation of allenic zinc 3a. Purification of the crude products by flash
chromatography (1% ethyl acetate in hexane) gave 36a (61%): 1H-
NMR δ 0.03 (9H, s), 0.11 (9H, s), 1.50 (2H, d, J ) 2.2 Hz), 1.5-1.7
(3H, m), 2.63 (1H, m), 2.99 (1H, m), 7.2-7.3 (5H, m); IR (liquid film)
1250 (s), 1170, 840, 745, 695 cm-1 (s); MS, m/z (relative intensity)
302 (M+, 2), 271 (4), 229 (30), 123 (47), 73 (100); HRMS calcd for
C18H30Si2; 302.1886, found; 302.1881.
9,9-Dimethoxy-1,4-bis(trimethylsilyl)-2-nonyne (36b). The reac-
tion of allenic zinc 26 (R ) (MeO)2CH(CH2)4), prepared by the reaction
of carbamate 1p with (TMSCH2)3ZnLi, with chlorotrimethylsilane (1.5
equiv) was carried out by a procedure similar to that described in a
general procedure for the silylation of allenic zinc 3a. Purification of
the crude products by flash chromatography (10% benzene in hexane)
gave 36b (49%): 1H-NMR δ 0.03 (9H, s), 0.07 (9H, s), 1.2-1.7 (11H,
m, including d (2H, J ) 2.8 Hz) at 1.44), 3.31 (6H, s), 4.36 (1H, t, J
) 5.7 Hz); 13C-NMR δ -3.09, -2.00, 7.28, 19.95, 24.34, 29.49, 29.67,
32.52, 52.60, 80.03, 104.64; IR (liquid film) 1930, 1250, 1125, 840
cm-1; MS, m/z (relative intensity) 328 (M+, <1), 177 (3), 89 (28), 73
(100); HRMS calcd for C17H36Si2O2; 328.2254, found; 328.2259. Anal.
Calcd for C17H36Si2O2: C, 62.13; H, 11.04. Found C, 62.15; H, 11.19.
2,2-Dimethyl-4-(2-phenylethyl)-7-trimethylsilyl-5-heptyn-3-one
(37a). The reaction of allenic zinc 26a with pivaloyl chloride (1.5
equiv) was carried out by a procedure similar to that described in a
general procedure for the acylation of allenic zinc 3a. Purification of
the crude products by flash chromatography (10-50% benzene in
hexane) gave 37a (49%): 1H-NMR (200 MHz) δ 0.08 (9H, s), 1.16
(9H, s), 1.46 (2H, d, J ) 2.6 Hz), 1.95 (2H, m), 2.5-2.8 (2H, m), 3.60
(1H, m), 7.2-7.3 (5H, m); IR (liquid film) 2220, 1710, 1250, 850,
745, 700 cm-1; MS, m/z (relative intensity) 314 (M+, 6), 313 (20),
299 (9), 257 (25), 91 (50), 73 (100); HRMS (CI) calcd for C20H31SiO
(MH+); 315.2144, found; 315.2150.
695 cm-1
.
6-Phenyl-1-(trimethylsilyl)-2,3-hexadiene (32a) and 1-(Trimeth-
ylsilyl)-6-phenyl-2-hexyne (33a). The reaction of mesylate 1a and
(TMSCH2)3ZnLi (2 equiv) was carried out by a procedure similar to
that described in a general procedure for the preparation of allenic zinc
3a-m. The D2O-quench of the reaction and purification of the crude
products by flash chromatography (1-5% benzene in hexane) gave
[2-2H]-32a (65%, 30%-d) and 33b (30%, <5%-d). 32a: H-NMR δ
1
0.02 (9H, s), 1.24-1.30 (2H, m), 2.23-2.34 (2H, m), 2.71 (2H, t, J )
7.8 Hz), 5.50-5.15 (2H, m), 7.13-7.32 (5H, m); IR (liquid film) 1955,
1245, 850, 840, 695 cm-1; MS, m/z (relative intensity) 230 (M+, 3),
156 (28), 91 (29), 73 (100), 59 (20); HRMS calcd for C15H22Si;
1
230.1491, found; 230.1509. 33a: H-NMR δ 0.10 (9H, s), 1.44 (2H,
t, J ) 2.7 Hz), 1.77 (2H, tt, J ) 6.9 and 7.7 Hz), 2.17 (2H, tt, J ) 2.7
and 6.9 Hz), 2.71 (2H, t, J ) 7.7 Hz), 7.15-7.3 (5H, m); IR (liquid
film) 2210, 1245, 850, 740, 695 cm-1; MS, m/z (relative intensity) 230
(M+, <1), 215 (2), 156 (7), 104 (25), 91 (9), 73 (100); HRMS calcd
for C15H22Si; 230.1491, found; 230.1478.
1-Cyclohexylidene-3-(trimethylsilyl)-1-propene (32b). The reac-
tion of chloride 1m and (TMSCH2)3ZnLi (2 equiv) was carried out by
a procedure similar to that described in a general procedure for the
preparation of allenic zinc 3a-m. The D2O-quench of the reaction
and purification of the crude products by flash chromatography
(pentane) gave [2-2H]-32b (71%, 31%-d). 32b: 1H-NMR δ 0.01 (9H,
s), 1.26 (2H, d, J ) 8.1 Hz), 1.54 (6H, m), 2.08 (4H, m), 4.93 (1H,
quintet of t, J ) 2.1 and 8.1 Hz); 13C-NMR δ 198.6, 101.5, 84.7, 32.1,
2,2,4-Trimethyl-7-trimethylsilyl-5-heptyn-3-one (37b). The reac-
tion of allenic zinc 26 (R ) Me), prepared by the reaction of carbamate
1q with (TMSCH2)3ZnLi, with pivaloyl chloride (1.5 equiv) was carried
out by a procedure similar to that described in a general procedure for
the acylation of allenic zinc 3a. Purification of the crude products by
flash chromatography (7% ethyl acetate in hexane) gave 37c (64%):
1H-NMR (200 MHz) δ 0.05 (9H, s), 1.20 (9H, s), 1.24 (3H, d, J ) 6.9
Hz), 1.41 (2H, d, J ) 2.6 Hz), 3.72 (1H, tq, J ) 2.6 and 6.9 Hz); IR
(liquid film) 2240, 1720, 1250, 1045, 850 cm-1; MS, m/z (relative
intensity) 224 (M+, 4), 209 (12), 147 (20), 73 (80), 57 (100); HRMS
calcd for C13H24SiO; 224.1596, found; 224.1594.
27.5, 26.2, 18.5, -2.0; IR (liquid film) 1960, 1245, 850, 810 cm-1
;
MS, m/z (relative intensity) 194 (M+, 10), 179 (10), 120 (8), 73 (100);
HRMS calcd for C12H22Si; 194.1492, found; 194.1491. Anal. Calcd
for C12H22Si: C, 74.14; H, 11.41. Found C, 73.99; H, 11.35.
Preparation of r-(Trimethylsilylmethyl)allenic Zinc 26a. To a
solution of (TMSCH2)3ZnLi (1.4 mmol) in THF at -85 °C was added
a solution of diphenylcarbamate 1d (0.7 mmol) in THF (1 mL). The
mixture was stirred at -15 °C for 1 h and then at rt for 2 h. After
addition of D2O (ca. 0.5 mL), the mixture was poured into 1 N HCl
and extracted three times with ether. The combined organic layers
were washed with NaHCO3 (5%), dried, and concentrated. The residue
(3R*,4S*)-2-Methyl-4-(2-phenylethyl)-7-trimethylsilyl-5-heptyn-
3-ol (38a). The reaction of allenic zinc 26a with 2-methylpropanal
(1.5 equiv) was carried out by a procedure similar to that described in
a general procedure for the preparation of homopropargyl alcohols.

Preparation of Allenic Zinc Reagents
J. Am. Chem. Soc., Vol. 118, No. 46, 1996 11389
Purification of the crude products by flash chromatography (5-15%
ethyl acetate in hexane) gave 38a (47%): 1H-NMR δ 0.12 (9H, s),
0.87 (3H, d, J ) 6.7 Hz), 0.95 (3H, d, J ) 6.7 Hz), 1.50 (2H, d, J )
2.5 Hz), 1.65-1.9 (4H, m), 2.50-2.94 (3H, m), 3.03 (1H, m), 7.15-
7.3 (5H, m); IR (liquid film) 3500 (br), 2225, 1250, 850, 750, 700
24.11, 28.48, 28.64, 32.44, 52.69, 82.41, 104.55, 109.40, 127.78, 129.21,
133.65, 137.82; MS, m/z (relative intensity) 304 (M+, <1), 273 (<1),
151 (62), 135 (64), 75 (100); HRMS calcd for C18H28SiO2; 304.1859,
found; 304.1858.
[2-(Dimethylphenylsilyl)ethenylidene]cyclohexane (42c) and 2-Cy-
clohexyl-1-(dimethylphenylsilyl)ethyne (43c). The reaction of chlo-
ride 1m with (PhMe2Si)3ZnLi (2 equiv) was carried out by a procedure
similar to that described in a general procedure for the preparation of
allenic zinc 3a-m. Purification of the crude products by flash
chromatography (0.5-5% ethyl acetate in hexane) gave 42c35 (72%)
and 43c36 (6%).
Preparation of r-(Phenyldimethylsilyl)allenic Zinc 29a. To a
solution of (PhMe2Si)3ZnLi (0.6 mmol) in THF at -85 °C was added
a solution of mesylate 40a (159 mg, 0.5 mmol) in THF (2 mL) and the
mixture was stirred for 15 min. After addition of CD3OD (ca. 0.5 mL),
the mixture was poured into 1 N HCl and extracted three times with
ether. The combined organic layers were washed with NaHCO3 (5%),
dried, and concentrated. The residue was purified by flash chroma-
tography (1-20% benzene in hexane) to give allene [1-2H]-42a (9%,
82%-d) and alkyne [1-2H]-43a (75%, 93%-d).
cm-1; MS, m/z (relative intensity) 259 (M+ - C3H7, 1), 230 (M+
-
Si(CH2)Me2, 10), 197 (8), 156 (34), 91 (42), 73 (100).
(3R*,4S*)-(5,5-Dimethoxypentyl)-2-methyl-7-trimethylsilyl-5-hep-
tyn-3-ol (38b). The reaction of allenic zinc 26 (R ) (MeO)2CH(CH2)4),
prepared by the reaction of carbamate 1p with (TMSCH2)3ZnLi, with
2-methylpropanal (1.5 equiv) was carried out by a procedure similar
to that described in a general procedure for the preparation of
homopropargyl alcohols. Purification of the crude products by flash
chromatography (10-30% ether in hexane) gave 38b (44%): 1H-NMR
δ 0.08 (9H, s), 0.89 (3H, d, J ) 6.6 Hz), 0.97 (3H, d, J ) 6.6 Hz),
1.2-1.8 (12H, m, including d (2H, J ) 2.5 Hz) at 1.45), 2.53 (1H, m),
2.99 (1H, dt, J ) 3.5 and 8.0 Hz), 3.30 (6H, s), 4.35 (1H, t, J ) 5.7
Hz); IR (liquid film) 3450 (br), 2220, 1130, 850 cm-1; MS (CI), m/z
(relative intensity) 297 (MH+ - MeOH, 8), 265 (28), 249 (6), 209
(25), 73 (100); HRMS (CI) calcd for C17H33O2Si (MH+ - MeOH);
297.2250, found; 297.2252.
(3R*,4S*)-6-(Dimethylphenylsilyl)-2-methyl-4-(2-phenylethyl)-5-
hexyn-3-ol (44a) and 7-Methyl-1-phenyl-5-(dimethylphenylsilyl)-3,4-
octadien-6-ol (47a). The reaction of allenic zinc 29a with 2-methyl-
propanal (1.5 equiv) was carried out using 1.6 equiv of ZnCl2 by a
procedure similar to that described in a general procedure for the
preparation of homopropargyl alcohols. Purification of the crude
products by flash chromatography (2.5-5% ethyl acetate in hexane)
(4S*,5R*)-10,10-Dimethoxy-4-methyl-1-trimethylsilyl-2-decyn-
5-ol (38c). The reaction of allenic zinc 26 (R ) Me), prepared by the
reaction of carbamate 1q with (TMSCH2)3ZnLi, with 6.6-dimethoxy-
hexanal (1.5 equiv) was carried out by a procedure similar to that
described in a general procedure for the preparation of homopropargyl
alcohols. Purification of the crude products by flash chromatography
(5-15% ethyl acetate in hexane) gave 38c (56%): Isolated by flash
1
gave 44a (52%) and 47a (14%). 44a: H-NMR δ 0.43 (6H, s), 0.90
1
chromatography (5-15% ethyl acetate in hexane); H-NMR δ 0.09
(3H, d, J ) 6.7 Hz), 0.96 (3H, d, J ) 6.6 Hz), 1.67 (1H, d, J ) 8.6
Hz), 1.81 (1H, m), 1.97 (1H, m), 2.65-2.85 (4H, m), 3.13 (1H, ddd,
J ) 3.8, 7.3, and 8.6 Hz), 7.15-7.45 (8H, m), 7.64 (2H, m); IR (liquid
film) 3560 (br), 3460 (br), 2160, 1250, 1115, 780, 730, 700 cm-1; MS
(CI), m/z (relative intensity) 351 (MH+, <1), 333 (2), 200 (60), 135
(100); HRMS (CI) calcd for C23H31SiO (MH+); 351.2144, found;
351.2142. Anal. Calcd for C23H30SiO: C, 78.80; H, 8.62. Found C,
78.87; H, 8.83. 47a: 1H-NMR δ 0.37 (3H, s), 0.39 (3H, s), 0.73 (3H,
d, J ) 6.7 Hz), 0.83 (3H, d, J ) 6.8 Hz), 1.36 (1H, d, J ) 6.8 Hz),
1.59 (1H, m), 2.33 (2H, m), 2.67 (2H, m), 3.78 (1H, ddd, J ) 2.4, 4.8,
and 6.8 Hz), 5.10 (3H, dt, J ) 2.4, and 6.9 Hz), 7.15-7.40 (8H, m),
7.52 (2H, m); IR (liquid film) 3550 (br), 3460 (br), 1935, 1250, 1110,
780, 700 cm-1; MS (CI), m/z (relative intensity) 333 (MH+ - H2O,
1), 297 (2), 200 (60), 135 (100); HRMS (CI) calcd for C23H29Si (MH+
- H2O); 333.2038, found; 333.2036.
(9H, s), 1.17 (3H, d, J ) 7.0 Hz), 1.34-1.64 (10H, m, including d
(2H, J ) 2.5 Hz) at 1.45), 1.78 (1H, brd, J ) ca. 7 Hz), 2.48 (1H, m),
3.3-3.4 (7H, m, including s (6H) at 3.31), 4.36 (1H, t, J ) 5.7 Hz);
IR (liquid film) 3470 (br), 2220, 1250, 1130, 850 cm-1; MS(CI), m/z
(relative intensity) 269 (MH+ - MeOH, 24), 237 (6), 147 (17), 129
(42), 115 (25), 73 (100); HRMS (CI) calcd for C15H29O2Si (MH+
MeOH); 269.1937, found; 269.1929.
-
1-(Dimethylphenylsilyl)-5-phenyl-1,2-pentadiene (42a) and 1-(Dim-
ethylphenylsilyl)-5-phenyl-1-pentyne (43a). The reaction of mesylate
1a with (PhMe2Si)3ZnLi (2 equiv) was carried out by a procedure
similar to that described in a general procedure for the preparation of
allenic zinc 3a-m. Purification of the crude products by flash
chromatography (1-5% benzene in hexane) gave 42a (85%) and 43a
1
(14%). 42a: H-NMR δ 0.26 (6H, s), 2.24-2.33 (2H, m). 2.66 (t, J
) 7.9 Hz), 4.87 (1H, q, J ) 6.7 Hz), 5.07 (1H, td, J ) 3.5 and 6.8
Hz), 7.15-7.4 (8H, m), 7.77 (2H, m); 13C-NMR δ 211.0, 141.8, 138.6,
133.7, 129.1, 128.4, 128.2, 127.7, 125.8, 83.4, 81.5, 36.0, 29.7, -2.27,
-2.32; IR (liquid film) 1935, 1245, 1110, 830, 810, 780, 730, 695
cm-1; MS, m/z (relative intensity) 278 (M+, 1), 200 (29), 185 (10),
135 (100); HRMS calcd for C19H22Si; 278.1492, found; 278.1486. 43a:
1H-NMR δ 0.40 (6H, s), 1.86 (2H, quintet, J ) 7.2 Hz), 2.28 (2H, t,
J ) 7.1 Hz), 2.74 (2H, t, J ) 7.8 Hz) 7.15-7.3 (8H, m), 7.65 (2H, m);
IR (liquid film) 2170, 1245, 1110, 835, 815, 775, 730, 695 cm-1; MS
(CI), m/z (relative intensity) 279 (MH+, 7), 263 (22), 200 (13), 185
(4), 125 (100), 91 (16), 65 (4); HRMS calcd for C19H22Si; 278.1492,
found; 278.1487.
(3S*,4R*)-3-(2-Phenylethyl)-10,10-dimethoxy-1-(dimethylphenyl-
silyl)-1-decyn-4-ol (44b) and 11,11-Dimethoxy-1-phenyl-5-(dimeth-
ylphenylsilyl)-3,4-undecadien-6-ol (47b). The reaction of allenic zinc
29a with 6,6-dimethoxyhexanal (1.5 equiv) was carried out using 1.6
equiv of ZnCl2 by a procedure similar to that described in a general
procedure for the preparation of homopropargyl alcohols. Purification
of the crude products by flash chromatography (2.5-5% ethyl acetate
1
in hexane) gave 44b (49%) and 47b (11%). 44b: H-NMR δ 0.43
(6H, s), 1.2-1.65 (8H, m), 1.69 (1H, d, J ) 7.8 Hz), 1.75-2.0 (2H,
m), 2.48 (1H, td, J ) 4.5, 5.2, and 9.7 Hz), 2.65-3.95 (2H, m), 3.30
(6H, m), 3.50 (1H, m), 4.34 (1H, t, J ) 5.7 Hz), 7.15-7.4 (m, 8H),
7.64 (2H, m); IR (liquid film) 3460 (br), 2170, 1250, 1125, 1120, 1055,
780, 725, 700 cm-1; MS (CI), m/z (relative intensity) 407 (MH+
-
8,8-Dimethoxy-1-(dimethylphenylsilyl)-1,2-octadiene (42b) and
8,8-Dimethoxy-1-(dimethylphenylsilyl)-1-octyne (43b). The reaction
of mesylate 1l with (PhMe2Si)3ZnLi (2 equiv) was carried out by a
procedure similar to that described in a general procedure for the
preparation of allenic zinc 3a-m. Purification of the crude products
by flash chromatography (0.5-5% ethyl acetate in hexane) gave 42b
CH3OH, 3), 375 (8), 223 (52), 129 (100); HRMS (CI) calcd for
1
C26H35O2Si (MH+ - CH3OH); 407.2406, found; 407.2414. 47b: H-
NMR δ 0.38 (3H, s), 0.39 (3H, s), 1.15-1.7 (9H, m), 2.33 (2H, m),
2.67 (2H, m), 3.29 (6H, s), 4.02 (1H, m), 4.30 (1H, t, J ) 5.7 Hz),
5.09 (1H, ddd, J ) 2.2, 6.7, and 8.7 Hz), 7.15-7.4 (m, 8H), 7.53 (2H,
m); IR (liquid film) 3450 (br), 1935, 1245, 1130, 775, 700 cm-1; MS
(CI), m/z (relative intensity) 407 (MH+ - CH3OH, <1), 389 (12), 223
(100), 135 (96); HRMS (CI) calcd for C26H33SiO (MH+ - CH3OH
and H2O); 389.2301, found; 389.2292.
6-(Dimethylphenylsilyl)-2,2-dimethyl-4-(2-phenylethyl)-5-hexyn-
3-one (45). The reaction of allenic zinc 29a with pivaloyl chloride
(1.5 equiv) was carried out by a procedure similar to that described in
a general procedure for the acylation of allenic zinc 3a. Purification
of the crude products by flash chromatography (2-10% ethyl acetate
in hexane) gave 45 (65%): 1H-NMR δ 0.39 (6H, s), 1.19 (9H, s), 2.05
(2H, m), 2.60-2.82 (2H, m), 3.71 (1H, dd, J ) 6.8 and 7.7 Hz), 7.15-
1
(89%) and 43b (5%). 42b: H-NMR δ 0.36 (6H, s), 1.38 (4H, m),
1.60 (2H, m), 1.98 (2H, m), 3.31 (6H, s), 4.34 (1H, t, J ) 5.7 Hz),
4.82 (1H, q, J ) 6.8 Hz), 5.04 (1H, td, J ) 3.6 and 6.8 Hz), 7.35 (3H,
m), 7.53 (2H, m); 13C-NMR (75.6 MHz, CDCl3) δ 211.1, 138.7, 133.6,
129.0, 127.7, 104.5, 83.7, 81.1, 52.61, 52.54, 32.3, 29.5, 27.7, 24.2,
-2.26, -2.30; IR (liquid film) 1940, 1250, 1130, 1115, 840, 820 785,
730, 700 cm-1; MS, m/z (relative intensity) 273 (M+ - MeO, <1),
182 (6), 135 (89), 89 (41), 75 (100). Anal. Calcd for C18H28SiO2: C,
71.00; H, 9.27. Found C, 70.85; H, 9.21. 43b: 1H-NMR δ 0.38 (6H,
s), 1.3-1.7 (8H, m), 2.28 (2H, t, J ) 7.0 Hz), 3.31 (6H, s), 4.35 (1H,
t, J ) 5.8 Hz), 7.36 (3H, m), 7.62 (2H, m); 13C-NMR δ -0.60, 19.88,

11390 J. Am. Chem. Soc., Vol. 118, No. 46, 1996
Harada et al.
7.4 (8H, m), 7.60 (2H, m); IR (liquid film) 2175, 1715, 1115, 820,
880, 700 cm-1; MS (CI), m/z (relative intensity) 363 (MH+, 28), 271
(71), 211 (94), 135 (100); HRMS (CI) calcd for C24H30SiO (MH+);
363.2144, found; 363.2140.
C27H32Si2 (M+); 412.2043, found; 412.2043. Anal. Calcd for C27H32-
Si2: C, 78.58; H, 7.81. Found C, 78.61; H, 7.94.
Acknowledgment. This work was supported partially by
Grant-in-Aid for Scientific Research on Priority Area of
Reactive Organometallics (No. 05236101) from the Ministry
of Education, Science, and Culture, Japan. We would like to
thank Prof. Sadao Miki (Kyoto Institute of Technology) for
FTIR measurements and helpful discussion.
1,3-Bis(dimethylphenylsilyl)-5-phenyl-1-pentyne (46). The reac-
tion of allenic zinc 29a with chlorodimethylphenylsilane (1.5 equiv)
was carried out by a procedure similar to that described in a general
procedure for the silylation of allenic zinc 3a. Purification of the crude
products by flash chromatography (10-20% benzene in hexane) gave
1
46 (57%) and 43a (13%). 46: H-NMR δ 0.37 (3H, s), 0.39 (3H, s),
Supporting Information Available: Additional information
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0.41 (6H, s), 1.65-1.75 (2H, m), 1.96 (1H, dd, J ) 6.8 and 7.7 Hz),
2.66 (1H, td, J ) 8.3 and 13.7 Hz), 2.96 (1H, td, J ) 7.1 and 13.7
Hz), 7.1-7.4 (6H, m), 7.52 (2H, m), 7.64 (2H, m); IR (liquid film)
2160, 1250, 1115, 815, 775, 700 cm-1; MS (CI), m/z (relative intensity)
413 (MH+, 2), 335 (8), 321 (10), 135 (100); HRMS (EI) calcd for
JA962136W