Prepackaged Ramberg-B?cklund reagents: Useful tools for organic synthesis

Article abstract of DOI:10.1016/j.tet.2004.06.032

The synthesis and reactions of several α,β-unsaturated chloromethyl sulfones is presented, for example [(chloromethyl)sulfonyl]-1,3- propadiene (4), [(chloromethyl)sulfonyl]ethene (5), [(dichloromethyl)sulfonyl] ethene (6) and (E,Z)-1,2-bis[(chloromethyl)

Full text of DOI:10.1016/j.tet.2004.06.032

Tetrahedron 60 (2004) 7525–7541
¨
Prepackaged Ramberg–Backlund reagents:
useful tools for organic synthesis
*
Eric Block, Hak Rim Jeon, David Putman and Shao-Zhong Zhang
Department of Chemistry,University at Albany, State University of New York, Albany, NY 12222, USA
Received 29 March 2004; revised 28 May 2004; accepted 4 June 2004
Available online 21 July 2004
Dedicated to Professor Dieter Seebach on the occasion of the 2003 Tetrahedron Prize with admiration and respect for his many seminal contributions to
chemistry, particularly his elegant work in the fields of organosulfur and organoselenium chemistry which has served as an inspiration for our own work
Abstract—The synthesis and reactions of several a,b-unsaturated chloromethyl sulfones is presented, for example [(chloromethyl)-
sulfonyl]-1,3-propadiene (4), [(chloromethyl)sulfonyl]ethene (5), [(dichloromethyl)sulfonyl]ethene (6) and (E,Z)-1,2-bis[(chloromethyl)-
¨
sulfonyl]ethene (7). These compounds serve as ‘prepackaged’ Ramberg–Backlund reagents, which following an appropriate first step, such
as Diels–Alder addition, react with base giving Ramberg–Backlund products.
¨
q 2004 Elsevier Ltd. All rights reserved.
1. Introduction
goes vinylogous Michael-induced RB (‘MIRB’) reaction
with sodium isopropoxide giving (E/Z)-1-isopropoxy-2,4-
pentadiene (Scheme 2).2e A related sequence involving the
adduct of 1 with styrene has been reported (Scheme 3).3
Reagent 1 adds to reactive single bonds giving adducts
which undergo the RB reaction (Scheme 4).4
¨
‘Prepackaged’ Ramberg–Backlund reagents may be defined
as compounds having sulfonyl and a-halogen groups which,
following an appropriate first step, require only base to give by
1
Ramberg–Backlund (‘RB’) reaction olefinic end products
¨
with an increase in total number of carbon atoms. In 1983,
we described the use of bromomethanesulfonyl bromide
(BrCH2SO2Br, 1) as a one-carbon example of such a
prepackaged reagent (Scheme 1).2 Reagent 1 readily
undergoes light-induced free radical addition to alkenes.
Dehydrobromination of the addition products followed by
vinylogous RB reaction gives 1,3-dienes as E,Z-mixtures.
Repetition of the process gives isomeric 1,3,5-trienes.
Scheme 2. Addition of 1 to 1,3-butadiene with dehydrobromination and
¨
Michael-induced Ramberg–Backlund (MIRB) reaction with NaOi-Pr.
1-[(Bromomethyl)sulfonyl]-1,3-butadiene, from sequential
reaction of 1,3-butadiene with 1 and triethylamine, under-
Scheme 3. Addition of 1 to styrene followed by dehydrobromination and
MIRB reaction with NaOMe.
Scheme 1. Use of BrCH2SO2Br (1) as a prepackaged RB reagent in an
iterative process affording 1,3,5-trienes.
¨
Keywords: Ramberg–Backlund reaction; a-Halosulfones.
*
Corresponding author. Tel.: þ1-518-4424459; fax: þ1-518-4423462;
e-mail address: eb801@albany.edu
Scheme 4. Addition of 1 to a strained single bond and then RB reaction.
0040–4020/$ - see front matter q 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2004.06.032

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E. Block et al. / Tetrahedron 60 (2004) 7525–7541
sulfones, as well as chloromethyl ethynyl sulfone (8) and
1-[(chloromethyl)sulfonyl]-1-haloethenes (CH2vC(X)SO2-
CH2Cl, 9a,b; X¼I or F, respectively). While a single
example of a dichloromethyl sulfone (6) is also included, in
the other cases dichloromethyl and trichloromethyl groups
could also replace the chloromethyl groups. None of these
compounds were known at the inception of this work.
Scheme 5. Tandem Diels–Alder RB reaction of CH2vC(Br)SO2CH3 (2).
An example of a three-carbon prepackaged RB reagent,
1-bromo-1-(methylsulfonyl)ethene (CH2vC(Br)SO2CH3,
2) was reported in 1972 (Scheme 5).5 In this case, reagent
2 underwent Diels–Alder addition followed by RB reaction.
A MIRB reaction (Scheme 6) involving benzyl 1-bromo-
vinyl sulfone (CH2vC(Br)SO2CH2Ph, 3) with various
nucleophiles has recently been described.6 In a preliminary
report in 1990 we showed that the four-carbon prepackaged
RB reagent [(chloromethyl)sulfonyl]-1,2-propadiene
(CH2vCvCHSO2CH2Cl, 4) upon tandem Diels–Alder
RB reaction gives the formal Diels–Alder adducts of buta-
1,2,3-triene.7 In a more recent preliminary report we
describe the syntheses and applications of the three- and
four-carbon prepackaged RB reagents [(chloromethyl)-
sulfonyl]ethene (CH2vCHSO2CH2Cl, 5), [(dichloro-
methyl)sulfonyl]ethene (CH2vCHSO2CHCl2, 6), and
(E,Z)-1,2-bis[(chloromethyl)sulfonyl]ethene (ClCH2SO2-
CHvCHSO2CH2Cl, 7), respectively.8 Our full experi-
mental results on these and related studies on prepackaged
RB reagents are reported here.
Compounds 4-9 should be powerful electron deficient
Diels–Alder dienophiles as well as 1,3-dipolarophiles in
1,3-dipolar additions since it is known that sulfonyl groups,
and in particular a-chloromethanesulfonyl groups, lower
the level of the LUMO in such compounds.9 It was
anticipated that several of these compounds might also
function as eneophiles in ene-reactions. Compound 9a
offers the possibility of replacing (by Stille/Heck type
reactions) the iodine by sp2- or sp-hybridized carbon
functionalities, giving compounds which might find use in
MIRB reactions, while 9b could afford new fluoroolefins.
2.1.1. Synthesis of [(chloromethyl)sulfonyl]-1,2-propa-
dienes 4 and homologues 13 and 14. It was anticipated that
4 could be prepared via a sequence involving coupling of
chloromethanesulfenyl chloride (ClCH2SCl, 10) with pro-
pargyl alcohol giving S-chloromethyl propargyl sulfenate
(11), [2,3]-sigmatropic rearrangement10a of 11 to [(chloro-
methyl)sulfinyl]-1,2-propadiene (12) and oxidation of 12 to
4 (Scheme 7). The success of our procedure depended in
part on our discovery that Douglass’ synthesis of 10
from the solid chlorination product of dimethyl disulfide,
CH3SCl3,10b can be substantially improved if the latter is
prepared and decomposed as a dilute solution in CH2Cl2.
Under these conditions, pure 10 can be conveniently and
safely prepared on a large scale in almost quantitative yield.
Formation of the sulfenate ester is best conducted by
reacting an ethereal solution of 1 equiv. of the lithium salt of
the propargylic alcohol at 278 8C with 10 and then
repeatedly filtering the mixture as it warms to remove
LiCl (which otherwise catalyzes decomposition). Concen-
tration affords 12, which on oxidation (mCPBA) affords 4 as
a low-melting, colorless solid.
Scheme 6. MIRB reaction of CH2vC(Br)SO2CH2Ph (3).
2. Results and discussion
2.1. Synthesis of potential prepackaged Ramberg–
¨
Backlund reagents
Figure 1 gives a sampling of the a,b-unsaturated chloro-
methyl sulfones we wished to examine as possible
prepackaged RB reagents. The examples include the
above described allenyl (4) and ethenyl (5-7) chloromethyl
Scheme 7. Synthesis of reagent 4 from propargyl alcohol.
Commercially available 2-methyl-3-butyn-2-ol and tetra-
dec-1-yn-3-ol (addition of ethynyl magnesium bromide11 to
dodecanal) were converted into 1-[(chloromethyl)sulfonyl]-
3-methylbuta-1,2-diene (Me2CvCvCHSO2CH2Cl, 13)
and [(chloromethyl)sulfonyl]-3-tetradeca-1,2-diene (CH3-
(CH2)10CHvCvCHSO2CH2Cl, 14), respectively, by the
method used to make 4. Allenes 13 and 14 were less prone
to decomposition than 4 and could be purified by column
chromatography, although purification is not necessary as
the crude compounds were at least 95% pure.
Figure 1. Potential prepackaged RB reagents.

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7527
Scheme 8. Synthesis of reagent 5.
2.1.2. Synthesis of [(chloromethyl)sulfonyl]ethene (5)
and [(dichloromethyl)sulfonyl]ethene (6). Treatment of
10 with ethylene gives the known12a 1-chloro-2-[(chloro-
methyl)thio]ethane (15; 90%) which, without purification, is
oxidized with 2 equiv. mCPBA (giving 16 (not isolated))
and stirred with aqueous NaHCO3 giving 5 (99%), a
colorless oil (Scheme 8). A similar sequence of steps can be
used to convert Cl2CHSCl (17; from chlorination of 10)10b
into 6 (78%) by way of 1-chloro-2-[(dichloromethyl)-
thio]ethane (18) and 1-chloro-2-[(dichloromethyl)sulfonyl]-
ethane (19), neither of which is isolated (Scheme 9).
Scheme 11. Synthesis of 8 from the known 1-chloromethanesulfanyl-2-
trimethylsilylethyne.
addition to the sulfoxide SvO at 1078 and the sulfone
bands at 1343 and 1161 cm21
.
2.1.5. Synthesis of 1-iodo-1-[(chloromethyl)sulfonyl]-
ethene (9a); attempted synthesis of 1-fluoro-1-[(chloro-
methyl)sulfonyl]ethene (9b). Treatment of aqueous solu-
tions of 5 with iodine monochloride followed by triethyl-
amine gave 1-iodo-1-[(chloromethyl)sulfonyl]ethene (9a)
(Scheme 12). Efforts to prepare 9b via addition of F2 (as a
5% mixture with N2)13c to 5 were unsuccessful.
Scheme 9. Synthesis of reagent 6.
2.1.3. Synthesis of (E/Z)-1,2-bis-[(chloromethyl)sulfonyl]-
ethene ((E/Z)-7). Dehydrochlorination of 15 with
(i-Pr)3SiOK12b gives [(chloromethyl)thio]ethene (20; 69%;
Scheme 10). Compound 20 is converted into (E/Z)-1,2-
bis-[(chloromethyl)sulfonyl]ethene ((E/Z)-7) by sequential
addition of 10 (giving 21; 96%), DBU dehydrochlorination
of 21 to (E/Z)-22 (58%; 1:3 E/Z), and oxidation with excess
dimethyldioxirane (DMDO)18b (giving 28% (E)-7 and 20%
(Z)-7; Scheme 10).
Scheme 12. Synthesis of 9a from 5.
2.2. Reactions of [(chloromethyl)sulfonyl]-1,2-
propadienes
We examined the Diels–Alder reactivity of 4, a potential
1,2,3-butatriene synthon. While (Z)-1,4-dichloro-2-butene
may also be considered a 1,2,3-butatriene synthon, as a
dienophile it requires “severe and carefully controlled
reaction conditions [typically several days at 190–
200 8C], was somewhat erratic”, gave only moderate yields,
Scheme 10. Synthesis of reagent 7.
2.1.4. Synthesis of [(chloromethyl)sulfonyl]ethyne (8).
Treatment of 2-(trimethylsilyl)ethynyllithium with sulfur
followed by BrCH2Cl gave the known chloromethyl tri-
methylsilylethynyl sulfide, TMSCuCSCH2Cl.13a,b While
this compound could be smoothly oxidized to the corre-
sponding sulfone, efforts to desilylate this latter compound
led to extensive decomposition. However, by reversing the
sequence of reactions, namely by first desilylating and then
oxidizing (2 equiv. DMDO), compound 8 could be directly
prepared (Scheme 11). With less than 2 equiv. of DMDO,
the corresponding sulfoxide, [(chloromethyl)sulfinyl]-
ethyne, HCuCS(O)CH2Cl, was obtained instead of 8.
The series of compounds including the known13a,b
HCuCSCH2Cl and new HCuCS(O)CH2Cl and
HCuCSO2CH2Cl (8) showed interesting trends in their
IR spectra, with uC–H at 3284, 3248 and 3242 cm21, and
CuC 2355/2332, 2050 and 2068 cm21, respectively, in
Scheme 13. Iterative cyclohomologation sequence using 4.
Scheme 14. Tandem Diels–Alder RB reaction of [(trichloromethyl)sulfo-
nyl]-1,2-propadiene.

¨
Table 1. Tandem Diels–Alder Ramberg–Backlund products from compounds 4–6, 13 and 14
¨
Ramberg–Backlund product
#
1
Diene
Dienophile
Diels–Alder adduct
Yield (%)
—
Yield (%)
85
4, 60 8C 30 min
—
—
—
23
24
25
2
3
4, 60 8C 3 h
4, 60 8C 2 h
—
—
85
68
4
5
4, 60 8C 2 h
4, 60 8C, 6 h
—
—
76
26
28
60
86
27
6
7
8
9
28
29
4, 60 8C 3 h
4, 60 8C 3 h
4, 80 8C 5 h
14, 80 8C 5 h
—
—
—
—
—
—
—
—
29
30
31
32
85
85
57
60
10
14, 80 8C 5 h
—
—
33
49

Table 1 (continued)
¨
Ramberg–Backlund product
#
Diene
Dienophile
Diels–Alder adduct
Yield (%)
—
Yield (%)
85
11
13, 80 8C 5 h
—
34
12
13
14
5, 120–130 8C 12 h
5, 120–130 8C 12 h
5, 155 8C 7 h
35
37
39
96
36
38
40
59a
51a
89
95b
96
15
16
17
5, 110 8C 16 h
5, 60 8C 12 h
5, 145 8C 7 h
41
43
97
92
76
42
44
79
75
90
28
45a
45b
47a
46a
46b
48a
18
19
5, 150 8C 12 h
74
93
67
47b
50
48b
51
6, 80–100 8C 16 h
72a
(continued on next page)

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E. Block et al. / Tetrahedron 60 (2004) 7525–7541
and does not react with either furan or 1,3-cyclohexa-
diene.14
When a 2:1 mixture of 1,2-bis(methylene)cyclohexane2e,f
and 4 was warmed to 60 8C for 3 h and the product 27
(Scheme 13) was diluted with THF, treated with 1 equiv. of
KOt-Bu at 0 8C, and worked up, triene 28 could be isolated
in 57% overall yield via RB reaction of 27. Repetition of the
process twice gave tetraene 29 and then pentaene 30, each in
85% overall yield. In these reactions 4 functions as a
synthon for 1,2,3-butatriene. The sequence of reactions
constitutes an iterative cyclohomologation approach to the
synthesis of fused 1,4-cyclohexadienes. This protocol has
been employed in syntheses of [n]beltenes.15 Use of [(tri-
chloromethyl)sulfonyl]-1,2-propadiene as a 1,1-dichloro-
1,2,3-butatriene synthon has also been described
(Scheme 14).16a
Table 1, entries 1–11, show the results of use of the above
procedure with Diels–Alder adducts obtained from reaction
of 4, 13 and 14 with cyclopentadiene, furan, furfural diethyl
acetal, 1,3-cyclohexadiene, 1,2-bis(methylene)cyclohexane,
28, 29, and 2,3-dimethyl-1,3-butadiene affording com-
pounds 23-34.
2.3. Reactions of [(chloromethyl)sulfonyl]ethene (5) and
[(dichloromethyl)sulfonyl]ethene (6)
We examined the Diels–Alder reactivity of new compounds
5 and 6, potential allene or chloroallene synthons. While
Diels–Alder adducts of allene are useful synthetic inter-
mediates, preparation of these compounds using allene itself
is generally impractical because of its cost, low reactivity,
lack of regioselectivity (Scheme 15) and the experimental
difficulties associated with gaseous reagents.16b Because of
the above problems, a variety of allene synthons have
been devised, such as 1-bromo-1-(methylsulfonyl)ethene,5
a-bromoacrolein,17a 2-(phenylsulfinyl)propene,17b ethenyl
triphenylphosphonium bromide,17c a-methylene-b-propio-
lactone,17d and 1,2-[bis(phenylsulfonyl)]propene.17e
Scheme 15. Diels–Alder reaction of allene with isoprene.
Both 5 and 6 readily add to a variety of 1,3-dienes giving
high yields of the corresponding Diels–Alder adducts, as
shown in Table 1, entries 12–22, and Scheme 16. As
anticipated, treatment of the Diels–Alder adducts of 5 with
KOt-Bu/THF give good yields of the diene–allene adducts
¨
via Ramberg–Backlund reaction (entries 12–16). Analogous
base treatment of adducts of 6 gave mixtures of the isomeric
adducts of chloropropa-1,2-diene together with lesser amounts
of the adducts of allene and 1,1-dichloropropa-1,2-diene
Scheme 16. Tandem Diels–Alder RB reaction of 5.

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7531
former case heating the 46a,b mixture with sulfur let to
aromatization affording 4-methyl-1-(40methylpent-30-enyl)-
benzene 46c as the major product, which in turn suggests
that the para adduct 45a of 5 with myrcene was the
predominant adduct (Scheme 19).
Scheme 17. Proposed mechanism for the reaction of a Diels–Alder adduct
of 6 with base.
(56, 42, 55, respectively, Scheme 17). The latter two
compounds are presumably formed by nucleophilic attack
of the a-sulfonyl-a-chlorocarbanion 54a of the Diels–Alder
adduct 54 of 6 on the chlorine of a second adduct molecule
giving [(trichloromethyl)sulfonyl]ethene adduct 54b, which
is not isolated.
Scheme 19. Reaction of 5 with myrcene, a 2-substituted 1,3-butadiene,
gives a mixture of adducts.
2.4. Reactions of (E/Z)-1,2-bis-[(chloromethyl)sulfonyl]-
ethene (7a/7b)
We reasoned that if base treatment of Diels–Alder adducts
of 6 were conducted in the presence of an excess of a
suitably reactive source of chlorine, chlorine transfer might
Both (E)- and (Z)-7 readily form Diels–Alder adducts, for
example, 57 and 58, respectively, with 1,3-cyclopentadiene
(Scheme 20), as confirmed by X-ray crystallography for 57,3
which also establishes the stereochemistry of (E)-7. The
X-ray structure of 57 shows SCCS and HCCH (the two
sulfur-bonded ring carbons) dihedral angles of
2110.58(16)8 and 124(3)8. Similarly, cis isomer 58 should
¨
be possible prior to Ramberg–Backlund reaction leading to
exclusive formation of Diels–Alder adducts of 1,1-dichloro-
propa-1,2-diene. To test this hypothesis, [(trichloromethyl)-
sulfonyl]methane, MeSO2CCl3 (49), was used as a novel
chlorine source. This little studied compound18a was
conveniently prepared in 91% yield by bubbling Cl2 into a
refluxing, UV-irradiated solution of dimethyl sulfone in
SO2Cl2 (Scheme 18). We were pleased to find that when
Diels–Alder adducts of 6 were treated at 0 8C with KOt-
Bu–THF in the presence of 2 equiv. of MeSO2CCl3, the
corresponding Diels–Alder adducts of 1,1-dichloropropa-
1,2-diene were formed in good yield (Table 1, entries
19–21), despite concerns about competing sulfonate
formation sometimes seen in reactions involving base
treatment of 1,1,1-trichloromethyl sulfones.18c
Scheme 18. Synthesis of [(trichloromethyl)sulfonyl]methane (49) and
CH2vCvCCl2 Diels–Alder adduct 55.
Mixtures of adducts were obtained on reaction of 5 or 6 with
2-substituted 1,3-dienes, for example, myrcene (76%; 2.3:1
para/meta mixture 45a,b with 5) and 2-t-butyl-1,3-buta-
diene (74%, 2.6:1 para/meta mixture 47a,b). Individual
adducts could not be separated chromatographically from
the isomeric mixtures. Treatment of the mixtures of adducts
with base afforded isomeric allene adducts 46a,b and 48a,b
of myrcene and 2-t-butyl-1,3-butadiene, respectively. In the
Scheme 20. Reaction of 57 and 58 with base; alternative synthesis of 59 via
Diels–Alder addition of 8.

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E. Block et al. / Tetrahedron 60 (2004) 7525–7541
have H on C(26) or C(27) far from syn or anti-periplanar
with sulfur.
pared reagents which have considerable utility as pre-
¨
packaged Ramberg–Backlund reagents. When combined
with Diels–Alder addition, these compounds conveniently
afford in good yields the formal adducts of 1,2,3-butatriene
(from 4), allene (from 5) and 1,1-dichloroallene (from 6;
when used in conjunction with a chlorine source such as
[(trichloromethyl)sulfonyl]methane) 49.
Base treatment of 57 or 58 gave unstable 2-[(chloromethyl)-
sulfonyl]bicyclo[2.2.1]hepta-2,5-diene (59) rather than
5,6-bis(methylene)bicyclo[2.2.1]hept-2-ene (60), for
example, 1,2-elimination from the activated a-sulfonyl
carbanions is favored over 1,3-elimination (Ramberg–
¨
Backlund reaction), even with the adduct of (Z)-7, where
a coplanar 1,2-elimination transition state is impossible.
Compound 59 could be directly prepared in high yield
from Diels–Alder addition of [(chloromethyl)sulfonyl]-
ethyne (8) to cyclopentadiene (Scheme 20).
4. Experimental
4.1. Caution
b-Chlorosulfides may be toxic on inhalation, ingestion or
skin contact. These compounds should only be handled in a
well-ventilated hood using rubber gloves. All glassware
used should be rinsed with bleach (‘Clorox’) immediately
after use.
Since compound 7 showed good reactivity as a dienophile,
we examined its reactivity in the ene reaction. When (E)-7
was heated with 2 equiv. of b-pinene in toluene at 135 8C
for 1.5 h, the ene product 2-{[(10,20-bis(chloromethyl)sulfo-
nyl]propyl}-6,6-dimethylbicyclo[3.1.1]hept-2-ene (61) was
formed in 72% yield as a crystalline solid. Base treatment
(KOt-Bu) of 61 in refluxing THF afforded (E)-2-(buta-1,3-
dienyl)-6,6-dimethylbicyclo[3.3.1]hept-2ene (63) in low
yield. If treatment with base was conducted at 0 8C, low
yields of 2-[(3-chloromethyl)sulfonyl]allyl-6,6-dimethyl-
bicyclo[3.3.1]hept-2-ene (62) could be isolated, leading to
the overall proposed mechanism shown in Scheme 21.
While not of synthetic utility due to low yield, the reaction
in Scheme 21 represents the first example of a tandem
reaction sequence incorporating an ene-reaction with
4.2. General methods
Reaction flasks were oven dried and cooled under nitrogen.
Diethyl ether and THF were distilled from sodium-
benzophenone ketyl; CH2Cl2 was distilled from CaH2.
Propargyl alcohol was distilled prior to use. Unless
otherwise noted, silica gel (Fisher Scientific Co., 200–425
˚
mesh, 60 A) was used as the chromatography solid phase
1
and solutions were dried over anhydrous MgSO4. H and
13C NMR spectra were recorded on a Varian Gemini at 300
and 75.1 MHz, respectively, in CDCl3 unless otherwise
noted, with all shifts referenced to TMS in ppm. IR spectra
were recorded on a Perkin Elmer model 1600 FTIR or a
Perkin Elmer 710B spectrophotometer. LR GC–MS was
performed on a Hewlett Packard 5890 GC coupled to a
Hewlett Packard 5970 MS (EI at 70 eV). Melting points
were determined on a Buchi model 510 melting point
apparatus and are uncorrected.
¨
Ramberg–Backlund elimination.
4.2.1. Chloromethanesulfenyl chloride (10). A magnetic
stirrer-equipped flask was charged with CH2Cl2 (60 mL)
and Me2S2 (9.16 g, 97 mmol), the mixture was cooled to
278 8C and Cl2 gas was bubbled through slowly using a
9 mm glass tube (a solid was formed plugging smaller bore
tubes). The mixture turned red-orange and a colorless solid
(CH3SCl3) appeared. The mixture turned into a milky,
yellow-white slurry, which continued to thicken and lighten
until the solution became saturated with chlorine, at which
time the mixture took on a yellow-green color. Addition of
Cl2 was stopped and a reflux condenser with drying tube
was fitted to the flask. Decomposition of CH3SCl3 was
promoted by warming the flask to room temperature. An
orange liquid formed as HCl was evolved. Concentration in
vacuo yielded the known 1010b as a malodorous, lachryma-
tory oil (20 g, 88%) which was used without further
purification; 1H NMR d 5.12 (s); 13C NMR d 54.8. If
desired, 10 can be purified by distillation (bp 50–55 8C/
115 mm).
Scheme 21. Ene-reaction of (E)-7 with b-pinene followed by RB reaction
of b-elimination product 62.
Efforts to use easily prepared 8 as an eneophile with
b-pinene did not appear to be promising due to the thermal
instability of 8. In addition, efforts to replace the iodine
atom of 9a with sp2- or sp-hybridized carbon groups through
Pd(0)-catalyzed reactions have not been successful thus far.
3. Conclusion
4.2.2. 1-[(Chloromethyl)sulfonyl]-1,2-propadiene (4). To
a solution of propargyl alcohol (4.8 mL, 80 mmol) in ether
(240 mL) was added n-BuLi (2.5 M, 32 mL, 80 mmol,
hexane) at 278 8C. The resultant thick colorless suspension
was stirred for 20 min. Neat ClCH2SCl (10; 6.6 mL) was
We have demonstrated that [(chloromethyl)sulfonyl]-1,3-
propadiene (4), [(chloromethyl)sulfonyl]ethene (5), and
[(dichloromethyl)sulfonyl]ethene (6) are new, easily pre-

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7533
added dropwise during 10 min. The mixture was stirred at
278 8C for 30 min, LiCl was removed by vacuum filtration
through a silica gel pad, and the light yellow solution was
concentrated in vacuo. The residue was dissolved in CH2Cl2
(80 mL). A solution of m-CPBA (77%, 26 g) in CH2Cl2
(200 mL) was added and the mixture was stirred at room
temperature for 16 h. The colorless precipitate was removed
by filtration, the filtrate was concentrated, and the residue
was chromatographed (silica gel; 1:5 EtOAc/hexane)
affording 4 as an oil or low melting solid, mp 39–39.5 8C
(s) cm21; EI HRMS calcd for C14H27SO2Cl: 306.1420.
Found: 306.1425.
4.2.5. 1-Chloro-2-[(chloromethyl)thio]ethane (15). A
solution of ClCH2SCl (10; 19.2 g, 17.8 mmol) in CH2Cl2
(200 mL) was placed in a flask fitted with a gas inlet tube
and a drying tube. Ethylene gas was slowly introduced at
0 8C until the starting material disappeared as indicated by
1H NMR analysis. Concentration in vacuo afforded the
known12 15 as a yellow oil (21.4 g, 90%) which was used
directly for the next step without further purification; bp
99–100 8C (15 mm); 1H NMR d 4.75 (s, 2H), 3.76 (t,
J¼7.8 Hz, 2H), 3.11 (t, J¼7.8 Hz, 2H); 13C NMR d 49.2,
42.4, 34.0; GC–MS m/z 146 (Mþ, 37Cl, 14%), 144 (Mþ,
35Cl, 20%), 111 (23%), 109 (63%), 95 (51%), 45 (100%).
1
(7.2 g, 59%); H NMR d 6.26 (t, J¼6.3 Hz, 1H), 5.62 (d,
J¼6.3 Hz, 2H), 4.53 (s, 2H); 13C NMR d 212.3 (vCv),
95.2 (vCH), 84.3 (vCH2), 58.3 (CH2); IR 3000 (m), 1965
.
(m), 1328 (s), 1247 (m), 1148 (s), 1120 (s), 872 (m) cm21
EI HRMS calcd for C4H5SO2Cl: 151.9698. Found:
151.9695. It is best to immediately oxidize the unstable
intermediate 12, which can be isolated, purified and
characterized as colorless needles, mp 49–49.5 8C from
4.2.6. [(Chloromethyl)sulfonyl]ethene (5). m-Chloroper-
benzoic acid (77%, 107 g, 0.47 mol) was added to a solution
of 15 (30.8 g, 0.21 mol) in CH2Cl2 (750 mL) over 30 min at
room temperature and the mixture was stirred for 16 h. The
colorless precipitate was removed by filtration and excess
aqueous NaHCO3 was added to the filtrate which was stirred
for 16 h. The reaction mixture was washed with H2O
(3£200 mL) and brine (3£200 mL), and the organic phase
was separated, dried (Na2SO4) and concentrated in vacuo
affording 5 as a colorless oil (29.4 g, 99%); 1H NMR d 6.69
(dd, J¼9.7, 16.6 Hz, 1H), 6.50 (d, J¼16.6 Hz, 1H), 6.31 (d,
J¼9.7 Hz, 1H), 4.43 (s, 2H); 13C NMR d 56.6, 132.8, 134.1;
1
ether/hexanes; H NMR d 6.00 (t, J¼6 Hz, 1H), 5.30 (d,
J¼6 Hz, 2H), 4.40 (s, 2H); IR 3000 (m), 1925 (m), 1060
(s) cm21. It is also best to promptly purify the crude 4 by
chromatography.
4.2.3. 1-[(Chloromethyl)sulfonyl]-3-methylbuta-1,2-
diene (13). A 250 mL three-necked flask under N2 was
charged with diethyl ether (100 mL) and 2-methyl-3-butyn-
2-ol (1 g, 11.9 mmol). The solution was cooled to 278 8C
and n-BuLi (2.5 M, 4.76 mL, 11.9 mmol) was added
dropwise. After 15 min 10 (1.38 g, 11.9 mmol) was added
dropwise and the solution was stirred for 15 min. The
solution was then continuously vacuum filtered as it warmed
to room temperature. A sample of the product was
IR (CHCl3) 1149, 1325 (SO2) cm21
.
4.2.7. 1-Chloro-2-[(dichloromethyl)thio]ethane (18). A
three-necked round bottom flask was charged with Me2S2
(10 mL, 113 mmol) and CH2Cl2 (120 mL). The solution
was cooled to 278 8C and Cl2 gas was bubbled through
slowly for 3–5 min. The reaction mixture turned reddish
orange and a colorless solid precipitated (CH3SCl3). The
slurry continued to thicken until the solution had been
saturated with Cl2, at which time the mixture took on a
yellow-green color and the addition of Cl2 was stopped. The
reaction mixture was warmed to room temperature and
stirred for 1 h to give a bright orange solution with the
release of HCl gas, which was absorbed with aqueous NaOH
solution. The orange solution was cooled to 278 8C and Cl2
gas was bubbled through again. As before, a colorless solid
precipitated. The slurry continued to thicken until the
solution had been saturated with Cl2, at which time the
mixture took on a yellow-green color and the addition of Cl2
was stopped. The reaction mixture was warmed to room
temperature, stirred for 1 h, concentrated in vacuo and
diluted with CH2Cl2 (300 mL). The solution was cooled to
0 8C and ethylene gas was bubbled in through a glass tube
until the color of the solution lightened. Concentration in
vacuo afforded 18 as a yellow oil (37.2 g; 91%). The
product was used directly for the next step without further
purification; 1H NMR d 6.83 (s, 1H), 3.84 (t, J¼7.3 Hz, 2H),
3.33 (t, J¼7.3 Hz, 2H); 13C NMR d 73.9, 42.5, 34.1.
1
concentrated in vacuo and analyzed: H NMR d 5.90 (m,
1H), 4.35 (m, 2H), 1.83 (m, 6H); 13C NMR d 203.4 (C),
105.5 (C), 95.5 (CH), 58.2 (CH2), 20.0 (CH3), 19.8 (CH3);
IR (nmax) 3000 (s), 1950 (m), 1060 (vs) cm21. To the pale
yellow solution was added CH2Cl2 (50 mL) and m-CPBA
(50–60%) (3.75 g, 11.9 mmol). The solution was stirred
overnight protected with a drying tube. The solution was
then washed with saturated aqueous NaHSO3 and NaHCO3
(3£ each). The organic layer was separated, dried and
concentrated in vacuo to give 13 (1.31 g, 61%), a colorless
1
oil: H NMR d 5.98 (m, 1H), 4.46 (s, 2H), 1.89 (d, J¼
3.3 Hz, 3H); 13C NMR d 207.5 (C), 107.3 (C), 92.6 (CH),
57.7 (CH2), 19.5 (CH3); IR (nmax) 3015 (m), 2950 (m), 1960
(m), 1320 (vs), 1115 (vs) cm21; mp ca. 10 8C; EI HRMS
calcd for C6H9SO2Cl: 180.0012. Found: 180.0018.
4.2.4. [(Chloromethyl)sulfonyl]-3-tetradeca-1,2-diene
(14). A 250 mL three-necked flask under N2 was charged
with diethyl ether (100 mL) and tetradec-1-yn-3-ol (2 g,
9.5 mmol). The flask was cooled to 278 8C and n-BuLi
(2.5 M, 3.8 mL, 9.5 mmol) was added dropwise. After
10 min 10 (1.1 g, 9.5 mmol) was added slowly with stirring.
Workup and overnight oxidation (m-CPBA; 1.6 g,
9.5 mmol) as for 4 gave a yellow oil. Chromatography
(5:1 CH2Cl2/hexane) gave 14 (2 g, 69% yield), a colorless
low melting solid: mp 37 8C; 1H NMR d 6.15 (m, 1H), 5.99
(m, 1H), 4.48 (s, 2H), 2.23 (m, 2H), 1.47 (m, 2H), 1.24 (br s,
16H), 0.86 (t, J¼7 Hz, 3H); 13C NMR d 208.9 (C), 101.3
(CH), 95.1 (CH), 57.9, 31.9, 29.5, 29.5, 29.4, 29.3, 29.3,
28.9, 28.4, 27.7, 22.7 (all CH2), 14.1 (CH3); IR (nmax) 2924
(vs), 2853 (vs), 1954 (m), 1465 (m), 1330 (s), 1147
4.2.8. [(Dichloromethyl)sulfonyl]ethene (6). m-Chloroper-
benzoic acid (77%, 27 g, 120 mmol) was added to a solution
of 18 (9.0 g, 50 mol) in CH2Cl2 (200 mL) over 30 min at
20 8C and the mixture was stirred for 16 h. The colorless
precipitate was removed by filtration. The filtrate was
concentrated and the residue chromatographed (silica gel;

7534
E. Block et al. / Tetrahedron 60 (2004) 7525–7541
6:1 hexane/EtOAc). The so-purified 19 was dissolved in
CH2Cl2 (200 mL), mixed with 1.1 equiv. of aqueous
NaHCO3 (excess NaHCO3 is detrimental) and stirred for
16 h. The mixture was washed with H2O (2£100 mL) and
brine (2£100 mL), dried (Na2SO4), concentrated in vacuo,
and chromatographed (5:1 hexane/EtOAc) to afford 6 as a
3:2) affording both the (E)-7 (Rf 0.8, 0.15 g, 28%) and the
(Z)-7 (Rf 0.6, 0.11 g, 20%) as colorless solids: (E)-7, mp
143–145 8C (EtOH); IR (film) 1389 (SO2), 1124
1
(SO2) cm21; H NMR (CD3C(O)CD3) d 7.82 (s, 2H), 5.22
(s, 4H); 13C NMR (CD3C(O)CD3) d 141.9, 57.2. Anal.
Calcd for C4H6Cl2O4S2: C, 18.98; H, 2.39. Found: C, 19.37;
H, 2.06. (Z)-7, mp 113–115 8C (EtOH); IR (film) 1329
1
low melting solid, mp 50–51 8C (7.5 g, 86%): H NMR d
1
6.86 (dd, J¼9.8, 16.6 Hz, 1H), 6.69 (d, J¼16.6 Hz, 1H),
6.55 (d, J¼9.8 Hz, 1H), 6.26 (s, 1H); 13C NMR d 78.7,
129.8, 137.3; IR (CHCl3) 1145, 1348 (SO2), 948,
3020 cm21 (CvC). Anal. Calcd for C3H4Cl2O2S: C,
20.59; H, 2.30. Found: C, 20.46; H, 2.07.
(SO2), 1119 (SO2) cm21; H NMR (CD3C(O)CD3) d 7.60
(s, 2H), 5.17 (s, 4H); 13C NMR (CD3C(O)CD3) d 141.8,
58.8.
4.2.13. [(Chloromethyl)sulfonyl]ethyne (8). A solution
of 1-(chloromethyl)thio-2-(trimethylsilyl)ethyne (1.5 g,
8.4 mmol)13a in methanol (2 mL) at 0 8C was treated
dropwise with Bu4NF (3.75 mL, 9.2 mmol; 75% aqueous
solution). The mixture was stirred at 0 8C for 2 h, and then
diluted with ice water and extracted with pentane. The
extracts were washed with cold water, dried (Na2SO4),
cooled to 0 8C, and treated overnight with a solution of
DMDO in acetone (18 mmol, 200 mL, 9 mmol/100 mL).
Solvents were removed in vacuo and the residue was
chromatographed (6:1 hexane/ethyl acetate), yielding the
4.2.9. [(Chloromethyl)thio]ethene (20). Triisopropylsila-
nol (0.1 mL, 0.5 mmol) was added to a slurry of pulverized
KOH (6.93 g, 0.12 mol) in tetraethyleneglycol dimethyl
ether (150 mL) and the mixture was stirred at room
temperature for 1 h. Compound 15 (2.91 g, 59 mmol) was
added to the mixture and the color changed from yellow to
dark brown. The mixture was stirred at 20 8C until the
starting material had disappeared as indicated by TLC (7:1
hexane/EtOAc, ca. 1.5 h). The mixture was then distilled
into a liquid nitrogen cooled trap (0.02 Torr). Compound 20
was separated as a colorless oil from the colorless
1
title compound (0.7 g, 60%) as a colorless oil: H NMR d
4.60 (s, 2H); 3.60 (s, 1H); 13C NMR d 91.7, 78.8, 60.6; IR
1
precipitate using a syringe (4.38 g, 69%): H NMR d 6.39
(neat) 3242 (triple bond C–H), 1342, 1159 cm21 (SO2).
(dd, J¼10, 17 Hz, 1H), 5.40 (dd, J¼2.4, 10 Hz, 1H), 5.39
(dd, J¼2.4, 17 Hz, 1H), 4.78 (s, 2H); 13C NMR d 129.0,
115.4, 47.8; GC–MS m/z 110 (Mþ, 37Cl, 9%), 108 (Mþ,
35Cl, 27%), 73 (88%), 46 (27%), 45 (100%).
4.2.14. 1-[(Chloromethyl)sulfonyl]-1-iodoethene (9a). To
a solution of 5 (1.41 g, 10 mmol) in 1:1 THF and water
(30 mL) was added iodine monochloride (3.25 g, 20 mmol)
at room temperature. The mixture was stirred overnight,
concentrated in vacuo, the residue was extracted with
CH2Cl2 (20£2 mL) and washed with aqueous sodium
thiosulfate solution (20 mL) giving 2-chloro-1-[(chloro-
methyl)sulfonyl]-1-iodoethane (1.2 g, 40%). A portion of
this latter compound (1.00 g, 3.3 mmol) in THF (15 mL)
was treated with triethylamine (3 mL) which was added
dropwise at room temperature. The mixture was stirred for
20 min, quenched with dilute HCl, extracted with CH2Cl2
(30£2 mL), dried, concentrated in vacuo and the residue
chromatographed (5:1 hexane/ethyl acetate) to yield 9a
(862 mg, 89%) as colorless crystals, mp 49–50 8C; 1H
NMR d 7.55 (d, J¼2.9 Hz, 1H), 6.81 (d, J¼2.9 Hz, 1H),
4.61 (s, 2H); 13C NMR d 144.1, 95.6, 52.6; IR (CH2Cl2)
1331, 1155 cm21 (SO2); EI-MS m/z 266 (Mþ, 28%), 152
(100%), 126 (56%). Anal. Calcd for C3H4ClIO2S: C, 13.52;
H, 1.51. Found: C, 13.93; 2.53.
4.2.10. 1-Chloro-1,2-bis[(chloromethyl)thio]ethane (21).
Compound 20 (3.03 g, 28 mmol) was added to ClCH2SCl
(3.28 g, 28 mmol) in CH2Cl2 (50 mL) at 0 8C. The reaction
mixture was stirred at room temperature for 1 h and
concentrated in vacuo affording the title compound as a
yellow oil (5.78 g, 96%). The product was used directly
1
without further purification; H NMR d 5.53 (t, J¼7 Hz,
1H), 4.98 and 4.80 (ABq, J¼11 Hz, 2H), 4.78 (s, 2H), 3.41
(d, J¼7 Hz, 2H); 13C NMR: d 64.4, 49.3, 46.7, 38.9; GC–
MS m/z 227 (Mþ, 37Cl, 10%), 225 (Mþ, 35Cl, 29%), 108
(94%), 97 (43%), 95 (100%).
4.2.11. (E,Z)-1,2-Bis[(chloromethyl)thio]ethene ((E,Z)-
22). 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU, 1.66 mL,
11 mmol) was added to a solution of 21 (1.42 g, 5.5 mmol)
in CHCl3 (50 mL) at 0 8C and the reaction mixture was
heated to reflux for 1 h. The reaction progress was
monitored by GC. The organic layer was washed with
0.5 N HCl (2£25 mL), NaHCO3 solution (2£25 mL), brine
(2£25 mL), dried (Na2SO4) and concentrated in vacuo.
Distillation gave (E,Z)-22 as a light yellow oil (0.61 g, 58%;
4.2.15. 5,6-Bis(methylene)bicyclo[2.2.1]hept-2-ene (23)
[Table 1, entry 1]. A 2 mL screw capped vial was charged
with 4 (0.5 g, 3.3 mmol), freshly distilled cyclopentadiene
(0.65 g, 9.9 mmol), sealed and held at 60 8C. By GC, the
reaction was found to be complete in 30 min (GC–MS m/z
218 (Mþ, 0.77%), 105 (100%), 103 (25%), 79 (50%), 77
(42%), 39 (23%)). The product was placed in a 50 mL flask,
dissolved in THF (10 mL) under N2, cooled to 0 8C and a
solution of KOt-Bu (0.57 g, 3.3 mmol) in THF (5 mL) was
added dropwise. The solution was stirred for 15 min and
quenched with saturated aqueous NH4Cl. Diethyl ether
(10 mL) was added and the organic layer was removed,
dried, and concentrated in vacuo. Chromatography (pen-
tane) gave known compound 2314a,19 slightly contaminated
with dicyclopentadiene (0.32 g, 85%): 13C NMR d 149.1
(C), 132.1 (CH), 101.2 (CH2), 51.2 (CH), 50.3 (CH2); GC–
1
E/Z 1.3:1), bp 90–100 8C (0.02 Torr); H NMR. d 6.48 (s,
2H), 6.46 (s, 2H), 4.76 (s, 8H); 13C NMR d 124.1, 123.5,
48.7, 48.5; GC–MS m/z 190 (Mþ, 37Cl, 33%), 190 (Mþ,
35Cl, 45%), 106 (93%), 104 (100%), 103 (70%).
4.2.12. (E,Z)-1,2-Bis[(chloromethyl)sulfonyl]ethene
((E,Z)-7). Dimethyldioxirane18b (DMDO; 100 mL,
9.0 mmol) was added to a solution of 22 (0.4 g, 2.1 mmol)
in CHCl3 (5 mL) at room temperature and the reaction
mixture was stirred at room temperature overnight. The
resulting mixture was dried (Na2SO4), concentrated in
vacuo, and the residue chromatographed (hexanes/EtOAc

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7535
MS m/z 118 (Mþ, 54%), 117 (97%), 91 (40%), 66 (100%),
65 (36%), 51 (44%), 50 (29%), 39 (75%).
(CH2), 42.3 (CH), 26.1 (CH2); GC–MS, m/z 132 (Mþ,
11%), 105 (9%), 104 (100%), 91 (9%), 78 (34%), 77 (17%),
51 (18%), 50 (9%), 39 (20%).
4.2.16. 5,6-Bis(methylene)-7-oxabicyclo[2.2.1]hept-2-ene
(24) [Table 1, entry 2]. A 2 mL screw capped vial was
charged with 4 (0.5 g, 3.3 mmol), furan (0.67 g, 9.9 mmol),
sealed and maintained at 60 8C. The reaction was complete
in 3 h according to GC analysis. The product was placed in a
50 mL flask, dissolved in THF (10 mL) under N2, cooled to
0 8C and a solution of KOt-Bu (0.57 g, 3.3 mmol) in THF
(5 mL) was added dropwise. The solution was stirred for
15 min and quenched with saturated aqueous NH4Cl.
Diethyl ether (10 mL) was added, and the organic layer
was separated, dried, concentrated in vacuo and chromato-
graphed (pentane) giving known 2420 (0.34 g, 85%) as a
colorless oil: 1H NMR d 6.74 (br s, 2H), 5.28 (br s, 2H), 5.16
(br s, 2H), 5.12 (br s, 2H); 13C NMR d 143.2 (C), 135.6
(CH), 102.6 (CH2), 82.8 (CH); GC–MS m/z 120 (Mþ, 2%),
92 (16%), 91 (100%), 68 (63%), 65 (36%), 63 (15%), 52
(28%), 51 (26%), 50 (19%), 39 (54%); EI HRMS calcd for
C8H8O: 120.0575. Found: 120.0569.
4.2.19. 2-[(Chloromethyl)sulfonyl]-3-methylene-1,2,3,4,
5,6,7,8-octahydronaphthalene (27) [Table 1, entry 5]. A
100 mL round-bottomed flask fitted with a reflux condenser
was charged with 1,2-bis(methylene)cyclohexane (2.16 g,
20 mmol) and 4 (6.1 g, 40 mmol) under argon. The mixture
was heated to 60 8C, stirred for 6 h, concentrated in vacuo,
and chromatographed (6:1 hexane/EtOAc) giving 27
(3.95 g, 76%) as a colorless oil; 1H NMR d 5.23 (d,
J¼3.1 Hz, 2H); 4.48 (dd, J¼12.6, 144 Hz, 2H), 2.90 (dd,
J¼18.9, 113 Hz, 2H), 2.40–2.65 (m, 2H), 1.73–2.00 (m,
4H), 1.41–1.73 (m, 4H); 13C NMR d 137.7, 127.1, 123.6,
117.3, 60.3, 52.3, 35.4, 29.6, 29.3, 28.1, 22.7, 22.5. GC–MS
m/e 147 (49%), 146 (30%), 131 (100%), 118 (81%), 117
(38%), 105 (77%), 104 (35%), 103 (15%), 91 (68%), 79
(32%), 78 (19%), 77 (38%), 67 (17%), 65 (25%), 53 (15%),
51 (25%), 49 (32%), 41 (33%), 39 (33%).
4.2.20. 1,2,3,4,5,6,7,8-Octahydro-2,3-bis(methylene)-
naphthalene (28) [Table 1, entry 5]. 2-[(Chloromethyl)-
sulfonyl]-3-methylene-1,2,3,4,5,6,7,8-octahydronaphthalene
(1.9 g, 7.29 mmol) in THF (10 mL) was cooled to 0 8C
under argon. A solution of KOtBu in THF (1 M, 16 mL,
16 mmol) was added dropwise. The mixture was stirred for
30 min and was quenched with saturated aqueous NH4Cl.
Diethyl ether was added and the organic layer was dried.
The solvents were removed in vacuo and the residue was
passed through a short column (5 cm; pentane) and the
solution was concentrated again giving known 2821 as a
colorless oil (1.0 g, 86%); 1H NMR d 5.08 (d, J¼2 Hz, 2H),
4.75 (d, J¼2 Hz, 2H), 2.81 (s, 4H), 1.91 (br s, 4H), 1.62
(quin., J¼3.3 Hz, 4H); 13C NMR d 146.0, 126.7 (both C),
108.1, 38.6, 29.7, 23.0 (all CH2); GC–MS m/z 160 (Mþ,
64%), 145 (29%), 131 (32%), 117 (76%), 115 (36%), 92
(55%), 91 (100%), 77 (36%), 41 (37%), 39 (57%).
4.2.17. 5,6-Bis(methylene)-7-oxabicyclo[2.2.1]hept-2-
ene-1-carboxaldehyde diethylacetal (25) [Table 1, entry
3]. A 2 mL screw capped vial was charged with 4 (0.5 g,
3.3 mmol), 2-(bis(ethoxy)methyl) furan (1.2 g, 7.1 mmol)
and sealed. The mixture was heated for 2 h at 60 8C. A
25 mL three-necked flask was charged with the product in
THF (5 mL) under N2. The flask was cooled to 0 8C and a
solution of KOt-Bu (0.37 g, 3.3 mmol) in THF (5 mL) was
added dropwise. The deep red solution was stirred for
15 min, quenched with saturated aqueous NH4Cl, and the
organic layer was separated, dried and concentrated in
vacuo to yield a pale yellow oil. Chromatography (CH2Cl2/
1
hexane (5:1)) gave 25 (0.5 g; 68%) as a colorless oil: H
NMR d 6.51 (d, J¼5.1 Hz, 1H), 6.34 (dd, J¼5.1, 2.8 Hz,
1H), 5.34 (s, 1H), 5.24 (s, 1H), 5.16 (br s, 1H), 5.06 (s, 1H),
4.97 (s, 1H) 3.91 (m, 1H), 3.73 (m, 3H), 1.29 (t, J¼6.7 Hz,
3H), 1.24 (t, J¼6.7 Hz, 3H); 13C NMR d 150.1, 143.2 (both
C), 135.6, 135.5, 103.0 (all CH), 101.7, 100.4 (both CH2),
82.2, 71.7 (both CH), 63.9, 63.7 (both CH2), 15.4, 15.3 (both
CH3); GC–MS m/z 222 (Mþ, 0.1%), 125 (17%), 103 (50%),
97 (20%), 91 (30%), 75 (52%), 65 (19%), 47 (100%), 39
(23%); EI HRMS calcd for C13H18O3: 222.1256. Found:
222.1253.
4.2.21. 1,2,3,4,5,6,7,8,9,10-Decahydro-2,3-bis(methylene)-
anthracene (29) [Table 1, entry 6]. A 25 mL flask was
charged with 28 (1.0 g, 6.25 mmol) and
4 (0.8 g,
5.26 mmol). The mixture was heated for 3 h at 60 8C,
diluted with THF (5 mL), cooled to 0 8C and KOt-Bu
(0.59 g, 5.26 mmol) in THF (5 mL) was added dropwise.
The solution was stirred for 15 min, quenched with
saturated aqueous NH4Cl, diluted with diethyl ether, and
the organic layer was removed, dried, concentrated in
vacuo, and chromatographed (pentane) giving 29 (0.95 g;
85%) as a waxy solid: 1H NMR d 5.09 (d, J¼2 Hz, 2H), 4.75
(d, J¼2 Hz, 2H), 2.80 (m, 8H), 1.92 (br s, 4H), 1.62 (m, 4H);
13C NMR d 145.7, 125.5, 124.5 (all C), 108.3, 37.5, 36.7,
29.5, 23.2 (all CH2); GC–MS m/z 212 (Mþ, 80%), 197
(54%), 169 (60%), 155 (100%), 141 (52%), 129 (35%), 128
(37%), 115 (39%), 91 (40%), 77 (34%); EI HRMS calcd for
C16H20: 212.1565. Found 212.1559.
4.2.18. 5,6-Bis(methylene)bicyclo[2.2.2]oct-2-ene (26)
[Table 1, entry 4]. A 2 mL screw capped vial, charged
with 4 (0.5 g, 3.3 mmol) and 1,3-cyclohexadiene (0.79 g,
9.9 mmol) was sealed and kept at 60 8C. The reaction was
complete in 2 h as determined by GC. The reaction gave two
products in a 3:1 ratio: GC–MS m/z 232 (Mþ, 0.06%), 119
(26%), 91 (100%), 65 (18%), 51 (8%), 41 (11%), 39 (13%).
The products were placed in a 50 mL flask, dissolved in
THF (10 mL) under N2, cooled to 0 8C and a solution of
KOt-Bu (0.57 g, 3.3 mmol) in THF (5 mL) was added
dropwise. The solution was stirred for 15 min and quenched
with saturated aqueous NH4Cl. Diethyl ether (10 mL) was
added and the organic layer was separated, dried, concen-
trated in vacuo, and chromatographed (pentane) giving
known 2614a,19 (0.26 g, 60%) as a colorless oil: 1H NMR d
6.2 (m, 2H), 5.1 (s, 2H), 4.7 (s, 2H), 3.2 (m, 2H), 1.6 (m,
2H), 1.4 (m, 2H); 13C NMR d 147.1 (C), 133.3 (CH), 102.2
4.2.22. 1,2,3,4,5,6,7,8,9,10,11,12-Dodecahydro-2,3-bis-
(methylene)naphthacene (30) [Table 1, entry 7]. Com-
pounds 29 (0.5 g, 2.36 mmol) and 4 (0.36 g, 2.36 mmol)
was kept in a screw capped vial maintained at 60 8C for 3 h.
The product was then transferred to a 25 mL three-necked
flask, dissolved in THF (10 mL), cooled to 0 8C and KOt-Bu

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E. Block et al. / Tetrahedron 60 (2004) 7525–7541
(0.26 g, 2.36 mmol) in THF (3 mL) was added dropwise.
The solution was stirred for 15 min, quenched with
saturated aqueous NH4Cl, and the organic layer was
separated, dried, concentrated in vacuo, and chromato-
graphed (pentane) giving 30 (0.49 g, 85%) as a waxy solid:
1H NMR d 5.09 (d, J¼2 Hz, 2H), 4.77 (d, J¼2 Hz, 2H), 2.77
(m, 12H), 1.93 (br s, 4H), 1.61 (m, 4H); 13C NMR, d 146.1,
126.7, 125.6, 124.9 (all C), 108.3, 39.2, 38.5, 36.7, 29.7,
22.9 (all CH2); GC–MS m/z 264 (Mþ, 83%), 231 (57%),
203 (65%), 189 (100%); EI HRMS calcd for C20H24:
264.1878. Found: 264.1881.
(0.068 g, 1.0 mmol). The vial was sealed and kept at 120 8C
for 2 h. The product was dissolved in THF (5 mL) and
placed in a 50 mL three-necked flask under N2 at 5 8C. A
THF (5 mL) solution of KOt-Bu (0.37 g, 0.33 mmol) was
added dropwise giving a deep red color. Diethyl ether
(10 mL) was added and the organic layer was separated,
dried and concentrated in vacuo. Chromatography of the
deep red oil (CH2Cl2/hexane (5:1)) gave 33 (0.45 g, 49%) as
a colorless waxy solid: 1H NMR d 6.5 (d, J¼2 Hz, 2H), 5.65
(t, J¼4 Hz, 1H), 5.3 (m, 2H), 5.1 (m, 2H), 2.3 (m, 2H), 1.45
(m, 2H), 1.3 (s, 16H), 0.88 (t, J¼4 Hz, 3H); 13C NMR d
143.2 (C), 142.1 (C), 136.4, 135.4, 125.7 (all CH), 107.2
(CH2), 84.8 (CH), 84.5, 29.8, 29.7, 29.6, 29.5, 29.4, 29.3,
28.4, 22.7 (all CH2), 14.1 (CH3); GC–MS m/z 274 (Mþ,
0.6%), 133 (35%), 120 (33%), 105 (44%), 91 (100%), 55
(34%), 43 (66%), 41 (92%); EI HRMS calcd for C17H30O:
274.2297. Found 274.2293.
4.2.23. 1,2-Dimethyl-4,5-bis(methylene)cyclohexene (31)
[Table 1, entry 8]. A 2 mL screw capped vial was charged
with 4 (0.1 g, 0.66 mmol), 2,3-dimethyl-1,3-butadiene
(0.2 g, 2.4 mmol), sealed and maintained at 80 8C. The
reaction was complete in 5 h, as verified by GC (GC–MS m/
z 121 (26%), 120 (26%), 105 (100%), 93 (15%), 91 (32%),
79 (20%), 77 (25%), 65 (10%), 51 (13%), 49 (14%), 41
(16%), 39 (20%)). The product was placed in a 50 mL flask,
dissolved in THF (10 mL) under N2, cooled to 0 8C and a
solution of KOt-Bu (0.114 g, 0.66 mmol) in THF (5 mL)
was added dropwise. The solution was stirred for 15 min,
quenched with saturated aqueous NH4Cl, diluted with
diethyl ether (10 mL), and the organic layer was separated,
dried, and concentrated in vacuo. Chromatography (pen-
4.2.26. 5-Isopropylidene-6-(methylene)bicyclo[2.2.1]-
hept-2-ene (34) [Table 1, entry 11]. A screw capped vial
was charged with 13 (0.5 g, 2.78 mmol) and freshly distilled
cyclopentadiene (0.25 g, 3.79 mmol). By GC, the reaction
was complete after 1 h at room temperature. (GC–MS m/z
248 (Mþ, 37Cl, 0.65%), 246 (Mþ, 35Cl, 1.5%), 133 (80%),
105 (58%), 91 (100%), 77 (21%), 67 (23%), 66 (40%), 65
(27%), 55 (23%), 51 (21%), 49 (18%), 41 (43%), 39 (41%)).
The product was dissolved in THF (25 mL) and transferred
to a 50 mL three-necked round bottom flask. The solution
was cooled to 0 8C and a THF (5 mL) solution of KOt-Bu
(0.31 g, 2.78 mmol) was added dropwise, turning the
solution a deep red-black color. The solution was then
quenched with saturated aqueous NH4Cl, the organic layer
was separated, dried, concentrated in vacuo and the residue
chromatographed (pentane) giving the 34 slightly contami-
nated with dicyclopentadiene (0.31 g, 85%) by GC: 13C
NMR d 147.1 (C), 147.2 (C), 137.3 (CH), 137.4 (CH), 131.3
(C), 105.4 (CH2), 65.3 (CH2), 54.2 (CH), 52.1 (CH), 30.2
(CH3); GC–MS m/z 146 (Mþ, 54%), 131 (100%), 91 (74%),
80 (77%), 79 (85%), 77 (45%), 66 (42%), 65 (40%), 51
(38%), 41 (31%), 39 (83%); EI HRMS calcd for C11H14:
146.1096. Found 146.1099.
1
tane) gave 31 (0.05 g, 57%) as a colorless oil: H NMR d
5.08 (d, J¼2.2 Hz, 2H), 4.74 (d, J¼2.2 Hz, 2H), 2.85 (br s,
4H), 1.65 (br s, 6H); 13C NMR d 146.0 (C), 124.4 (C), 107.9
(CH2), 39.7 (CH2), 18.6 (CH3); GC–MS m/z 134 (Mþ,
38%), 119 (49%), 117 (17%), 105 (23%), 92 (18%), 91
(100%), 79 (20%), 77 (25%), 65 (17%), 51 (21%), 41
(37%), 39 (52%); EI HRMS calcd for C10H14: 134.1095.
Found 134.1094.
4.2.24. (E,Z)-5-Methylene-6-(undecylidene)bicyclo-
[2.2.1]hept-2-ene (32) [Table 1, entry 9]. A screw capped
vial was charged with 14 (0.1 g, 0.3 mmol), and freshly
distilled cyclopentadiene (0.07 g, 1.0 mmol). The tube was
sealed and maintained at 100 8C for 30 min. The reaction
was followed by TLC (CH2Cl2/hexane (5:1)). The product
was dissolved in THF (5 mL), placed in a 50 mL three-
necked flask under N2, and cooled to 5 8C. A THF (5 mL)
solution of KOt-Bu (0.033 g, 0.3 mmol) was added drop-
wise turning the solution a pale yellow color. The solution
was stirred for 15 min, quenched with saturated aqueous
NH4Cl, treated with diethyl ether (10 mL), and the organic
layer was separated, dried, concentrated in vacuo and
chromatographed (hexane) giving 32 (0.048 g, 60%) as a
4.2.27. 4-[(Chloromethyl)sulfonyl]-1,2-dimethylcyclo-
hexene (35) [Table 1, entry 12]. A mixture of 2,3-
dimethylbutadiene (3.2 mL, 28.6 mmol) and 5 (2.05 g,
14.6 mmol) in toluene (4 mL) was heated in a sealed tube
at 120–130 8C for 12 h. The product was concentrated in
vacuo and chromatographed (5:1 hexane/EtOAc) yielding
the title compound (3.12 g, 96%) as a colorless solid, mp
1
colorless oil: H NMR d 6.26 (br s, 2H), 5.55 (t, J¼4 Hz,
69–70 8C; IR (film) 1309 (SO2), 1146 (SO2) cm21 1H
;
1H), 5.15 (d, J¼4 Hz, 2H), 3.27 (br s, 1H), 3.18 (br s, 1H),
2.23 (m, 2H), 1.68 (dd, J¼8, 4 Hz, 2H), 1.41 (m, 2H), 1.29
(s, 16H), 0.88 (t, J¼4 Hz, 3H); 13C NMR d 150.3 (C), 137.5
(CH), 136.5 (CH), 125.4 (C), 124.6 (CH), 106.4 (CH2),
53.6, 52.7 (both CH), 31.9, 29.8, 29.7, 29.5, 29.5, 29.4, 29.2,
29.0, 28.9, 28.7, 22.7 (all CH2), 14.1 (CH3); GC–MS m/z
272 (Mþ, 0.2%), 131 (59%), 117 (57%), 91 (68%), 66
(61%), 43 (75%), 41 (100%); EI HRMS calcd for C20H32:
272.2504. Found 272.2501.
NMR d 4.43 (s, 2H), 3.47 (m, 1H), 2.41–2.07 (m, 5H), 1.71
(m, 1H), 1.60 (s, 3H), 1.57 (s, 3H); 13C NMR d 125.8, 122.0,
55.1, 53.6, 30.3, 29.5, 21.2, 18.8, 18.7. Anal. Calcd for
C9H15ClO2S: C, 48.53; H, 6.79 Found: C, 48.50; 7.44.
4.2.28. 1,2-Dimethyl-4-(methylene)cyclohexene (36)
[Table 1, entry 12]. A solution of KOt-Bu (12.0 mL,
12.0 mmol, 1 M) in THF was added to 4-chloromethane-
sulfonyl-1,2-dimethylcyclohexene (1.34 g, 6.0 mmol) in
THF (15 mL) at 0 8C. The mixture was heated at reflux
for 1 h and then treated with CH2Cl2 (150 mL) and water
(30 mL). The organic layer was washed with water
(10£30 mL), dried, filtered through a silica gel pad, and
4.2.25. (E,Z)-5-Methylene-6-undecylidene-7-oxabicyclo-
[2.2.1]hept-2-ene (33) [Table 1, entry 10]. A screw capped
vial was charged with 14 (0.1 g, 0.33 mmol) and furan

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7537
the solvent (CH2Cl2) was removed by distillation yielding
1
concentrated in vacuo, affording known 4017a as colorless
crystals (0.39 g, 89%), mp 104–105 8C (lit. mp 101–
102 8C17a); 1H NMR d 7.51–7.29 (m, 8H), 5.35 (br s, 1H),
4.94 (d, J¼10.2 Hz, 2H), 4.55 (m, 1H), 2.65 (m, 2H); 13C
NMR d 146.5, 143.4, 142.5, 126.2, 123.7, 123.6, 107.4,
107.4, 55.5, 45.0, 35.4; GC m/z (rel. intensity) 218 (Mþ, 28),
178 (100).
known 3617a as a colorless oil (429 mg, 59%); H NMR d
4.68 (s, 2H), 2.67 (s, 2H), 2.26 (t, J¼6.5 Hz, 2H), 2.07 (m,
2H), 1.61 (s, 6H); 13C NMR d 147.0, 125.8, 124.9, 106.4,
39.7, 39.7, 33.9, 32.3, 18.8; GC–MS m/z (rel. intensity) 122
(Mþ, 85), 107 (100), 91 (92), 79 (93).
4.2.29. 5-[(Chloromethyl)sulfonyl]bicyclo[2.2.2]oct-2-
ene (37) [Table 1, entry 13]. A mixture of 1,3-cyclohexa-
diene (2.72 mL, 28.6 mmol) and 5 (2.09 g, 14.9 mmol) in
toluene (1 mL) was heated in a sealed tube at 120–130 8C
for 12 h. The product was concentrated in vacuo and
chromatographed (5:1 hexane/EtOAc) yielding 37 (3.1 g,
95%) as a colorless oil which by NMR was a 6.3:1 endo/exo
mixture; exo: Rf 0.45 hexanes/EtOAc 5:1; IR (neat) 1319
4.2.33. 2-[(Chloromethyl)sulfonyl]-1,2,3,4,5,6,7,8-octa-
hydronaphthalene (41) [Table 1, entry 15]. A mixture
of 1,2-bis(methylene)cyclohexane (1.3 g, 12 mmol) and 5
(1.55 g, 11 mmol) in toluene (3 mL) was heated at 110–
120 8C in a sealed tube for 16 h, the mixture concentrated in
vacuo and chromatographed (5:1 hexane/EtOAc) to afford
1
41 (2.41 g, 97%) as colorless crystals, mp 81–82 8C; H
1
(SO2), 1146 (SO2), 1120 (SO2) cm21; H NMR d 6.39 (m,
NMR d 4.44 (s, 2H); 3.49–3.61 (m, 1H), 1.65–2.42
(m, 12H), 1.41–1.54 (m, 2H); 13C NMR d 128.4, 124.6,
55.1, 53.3, 30.1, 29.8, 29.2, 28.6, 22.8, 21.2; IR (neat), 725
(C–Cl), 1156 (s), 1332 cm21 (s, SO2). Anal. Calcd for
C11H17ClO2S C, 53.11; H, 6.89. Found, C, 52.78; H, 6.50
(see Scheme 18).
2H), 4.45 and 4.35 (ABq, J¼12.6 Hz, 2H), 3.30 (m, 1H),
3.18 (br s, 1H), 2.75 (br s, 1H), 1.20–2.24 (m, 6H); 13C
NMR d 136.1, 133.5, 56.5, 55.4, 29.3, 29.2, 27.3, 24.5, 20.4;
endo: Rf 0.36 hexanes/EtOAc 5:1; IR (neat) 1319 (SO2),
1147 (SO2), 1122 (SO2); 1H NMR d 6.41 (m, 1H), 6.28 (m,
1H), 4.35 (s, 2H), 3.60 (m, 1H), 3.17 (br s, 1H), 2.78 (br s,
1H), 1.24–2.04 (m, 6H); 13C NMR d 135.1, 130.4, 58.3,
54.3, 29.2, 29.0, 28.8, 26.1, 22.9.
4.2.34. 1,2,3,4,5,6,7,8-Octahydro-2-methylenenaphtha-
lene (42) [Table 1, entry 15]. A solution of KOtBu in
THF (1 M, 10.0 mL, 10.0 mmol) was added dropwise at
0 8C to 41 (1.24 g, 5.0 mmol) in THF (20 mL). The reaction
mixture was refluxed for 1 h., concentrated in vacuo, and the
residue was treated with ether (40 mL) and water (40 mL).
The layers were separated and the aqueous layer was
extracted with ether (3£40 mL). The combined ether layers
were washed with water (2£30 mL), dried, concentrated in
vacuo and chromatographed (pentane) to give 42 (584 mg,
79%) as a colorless oil; 1H NMR d 4.67 (s, 2H); 2.60 (s, 2H),
2.26 (t, J¼6.6 Hz, 2H), 2.00 (t, J¼6.1 Hz, 2H), 1.85 (br,
4H), 1.54–1.64 (m, 4H); 13C NMR d 147.0, 128.1, 127.3,
106.6, 38.6, 32.8, 32.1, 30.1, 30.0, 23.1, 23.0; EI MS: m/z
148 (Mþ, 100), 133 (38), 119 (27), 105 (48), 91 (28); IR
(neat) 2919 cm21 (CvCH), 1649 (CvC), 1443 (CvCH),
885 cm21 (CvCH).
4.2.30. 5-Methylenebicyclo[2.2.2]oct-2-ene (38) [Table 1,
entry 13]. A solution of KOt-Bu in THF (12 mL, 12 mmol,
1 M) was added to 37 (1.32 g, 6.0 mmol) in THF (15 mL) at
0 8C. The mixture was heated at reflux for 1 h and then
mixed with CH2Cl2 (150 mL) and water (30 mL). The
organic layer was washed with water (10£30 mL), dried,
and filtered through a silica gel pad. The solvent was
removed by distillation yielding known 3817c as a colorless
oil (366 mg, 51%): 1H NMR d 6.26 (m, 2H), 4.74 (m, 1H),
4.55 (m, 1H), 3.00 (m, 1H), 2.65 (m, 1H), 2.25–2.18 (m,
2H), 1.66–1.54 (m, 4H); 13C NMR d 150.7, 134.1, 133.0,
103.8, 41.0, 34.9, 31.4, 29.7, 26.5; GC–MS m/z (rel.
intensity) 120 (Mþ, 35), 92 (100), 91 (92), 79 (38), 77 (37).
4.2.31. 11-[(Chloromethyl)sulfonyl]-9,10-dihydro-9,10-
ethanoanthracene (39) [Table 1, entry 14]. A mixture of
anthracene (1.35 g, 7.14 mmol) and 5 (0.5 g, 3.57 mmol) in
toluene (1.5 mL) was heated in a sealed tube at 155 8C for
7 h. The reaction mixture was taken up in CHCl3 (30 mL),
anthracene (0.15 g) was removed by filtration, the filtrate
was concentrated in vacuo and the residue chromatographed
(1:1 pentane/CHCl3, then CHCl3) gave 39 as a colorless
solid (1.12 g, 96%), mp 143–145 8C; IR (film) 1322 (SO2),
4.2.35. 2-[(Chloromethyl)sulfonyl]-1,2,3,4,5,6,7,8,9,10-
decahydroanthracene (43) [Table 1, entry 16]. Com-
pound 5 (141 mg, 1.0 mmol) and 28 (320 mg, 2 mmol) were
sealed in a tube and the mixture was heated to 60 8C and
stirred for 12 h. The mixture was concentrated in vacuo and
chromatographed (6:1 hexane/EtOAc) to yield the title
compound (277 mg, 92%) as a colorless powder, mp
1
123–124 8C; H NMR d 4.45 (s, 2H); 3.54–3.64 (m, 1H),
1
1146 (SO2), 1118 (SO2) cm21; H NMR d 7.46–7.16 (m,
2.31–2.60 (m, 5H), 2.10–2.30 (m, 4H), 1.80–1.90 (m, 5H),
1.60–1.65 (m, 4H); 13C NMR d 126.2, 125.5, 125.3,
122.5, 73.1, 55.0, 53.3, 36.8, 29.3, 28.3, 27.8, 23.9, 23.0,
21.1; IR (CHCl3): 1161, 1322 cm21 (SO2). Anal. Calcd
for C15H21ClO2S: C, 59.88; H, 7.04. Found: C, 60.16; H,
6.65.
8H), 5.00 (d, J¼2.1 Hz, 1H), 4.86 (t, J¼2.7 Hz, 1H), 4.16
(ABq, J¼12.7, 2H), 3.74 (ddd, J¼2.4, 6.3, 9.3 Hz, 1H),
2.30–2.26 (m, 2H); 13C NMR d 143.3, 143.2, 140.9, 137.9,
127.1, 127.0, 126.6, 126.5, 125.6, 124.0, 124.0, 123.6, 59.5,
55.6, 43.5, 43.3, 30.2.
4.2.32. 9,10-Dihydro-11-methylene-9,10-ethanoanthra-
cene (40) [Table 1, entry 14]. A solution of KOt-Bu in
THF (4.08 mL, 4.08 mmol, 1 M) was added to 39 (0.67 g,
2.04 mmol) in THF (10 mL) at 0 8C. The reaction mixture
was heated at reflux for 1 h, concentrated in vacuo, and the
residue was treated with ether (20 mL) and water (20 mL).
The aqueous layer was extracted with ether (2£20 mL),
organic phase washed with water (2£20 mL), dried, and
4.2.36. 1,2,3,4,5,6,7,8,9,10-Decahydro-2-methylenean-
thracene (44) [Table 1, entry 16]. A solution of 2-[(chloro-
methyl)sulfonyl]-1,2,3,4,5,6,7,8,9,10-decahydroanthracene
(301 mg, 1 mmol) in THF (5 mL) was cooled to 25 8C
under Ar. A solution of KOtBu in THF (1 M, 2.0 mL,
2.0 mmol) was added dropwise. The mixture was stirred for
30 min and was quenched with saturated aqueous NH4Cl.
Diethyl ether was added and the organic layer was dried.

7538
E. Block et al. / Tetrahedron 60 (2004) 7525–7541
The solvents were removed in vacuo, the residue was
filtered through a short silica gel column (5 cm; pentane)
and the solution was concentrated again. Compound 44 was
obtained as a colorless oil (150 mg; 75%); 1H NMR d 4.70
(s, 2H), 2.64 (s, 2H), 2.41 (s, 4H), 2.31 (t, J¼6.5 Hz, 2H),
2.03 (t, J¼6.5 Hz, 2H), 1.86 (br, 4H), 1.54–1.64 (m, 4H);
13C NMR d 146.6, 126.0, 125.7, 125.6, 125.2, 107.0, 37.6,
37.2, 37.1, 32.1, 31.8, 29.4, 23.2; EIMS: m/z 200 (Mþ, 100),
157 (18), 145 (63), 129 (15), 117 (13); IR (neat) 2926
(CvCH), 1653 (CvC), 1436 (CvCH), 881 (CvCH) (see
Scheme 17).
4.2.39. 1-tert-Butyl-4-[(chloromethyl)sulfonyl]cyclo-
hexene and 1-tert-butyl-5-[(chloromethyl)sulonyl]cyclo-
hexene (47a,b) [Table 1, entry 18]. 2-tert-Butylbuta-1,3-
diene (825 mg, 7.5 mmol) and 5 (703 mg, 5 mmol) were
placed in a sealed tube and heated to 130–150 8C with
stirring for 12 h. Volatiles were removed in vacuo and the
residue was chromatographed (hexane/ethyl acetate, 6:1) to
yield 2.6:1 47a/47b (962 mg, 74%) as a colorless oil; 47a:
1H NMR d 5.40 (m, 1H), 4.44 (s, 2H), 3.38–3.48 (m, 1H),
1.60–2.40 (m, 6H), 1.00 (s, 9H); 47b had additional peaks at
d 5.42–5.45 (m, 1H), 4.47 (d, J¼3.21 Hz, 1H), 1.03 (s, 9H).
Anal. Calcd for C11H19ClO2S: C, 52.68; H, 7.64. Found: C,
52.10; H, 7.13.
4.2.37. 4-[(Chloromethyl)sulfonyl]-1-(4-methyl-1-pent-3-
enyl)cyclohexene and 5-[(chloromethyl)sulfonyl]-1-(4-
methyl-1-pent-3-enyl)cyclohexene (45a,b) [Table 1,
entry 17]. A mixture of myrcene (0.97 g, 7.14 mmol) and
5 (0.5 g, 3.57 mmol) in toluene (1.5 mL) was heated in a
sealed tube at 145 8C for 7 h; the mixture was concentrated
in vacuo and chromatographed (5:1 hexane/EtOAc) yield-
ing a 2.3:1 45a/45b mixture (0.75 g, 76%; an oil); IR (neat)
1320 (SO2), 1146 (SO2), 1119 (SO2) cm21; 1H NMR 45a, d
5.37 (m, 1H), 5.04 (m, 1H), 4.44 (s, 2H), 3.60–3.44 (m 1H),
2.38–1.95 (m, 10H), 1.65 (s, 3H), 1.56 (s, 3H); 45b had
additional peaks at d 5.47 (m, 1H), 4.67 (d, J¼15 Hz, 1H),
4.45 (s, 2H), 1.69 (s, 3H), 1.54 (s, 3H), integrated relative to
the minor component (45b) peaks; 13C NMR (45a) 138.0,
131.9, 123.6, 116.7, 55.0, 53.4, 37.3, 27.4, 26.8, 25.8, 24.0,
20.9, 17.7. Anal. Calcd for C13H21ClO2S: C, 56.40; H, 7.65.
Found: C, 56.48; 8.34.
4.2.40. 1-t-Butyl-4-(methylene)cyclohexene and 1-t-
butyl-5-(methylene)cyclohexene (48a, 48b) [Table 1,
entry 18]. A THF solution of KOt-Bu (1 M in THF,
4.4 mL, 4.4 mmol) was added dropwise to 47a,b (501 mg,
2.0 mmol) in THF (10 mL). The mixture was refluxed for
1 h, quenched with NH4Cl solution, concentrated in vacuo,
and the residue mixed with ether (20 mL) and water
(20 mL). The layers were separated and the aqueous layer
was extracted with ether (3£40 mL). The combined ether
layers were washed with water (3£15 mL), dried (MgSO4),
concentrated in vacuo, and the residue chromatographed
(pentane) yielding a 2.5:1 48a/48b mixture (200 mg, 67%)
1
as a colorless oil; 48a: H NMR d 5.29 (t, J¼3.6 Hz, 1H),
4.60 (s, 2H), 2.65–2.68 (m, 2H), 2.05–2.19 (m, 4H), 0.90
(s, 9H); 13C NMR d 146.6, 145.8, 116.6, 106.7, 35.3, 33.6,
31.6, 28.9, 27.0; 48b: 1H NMR d 5.40 (m, 1H), 4.62 (s, 2H),
2.65–2.68 (m, 2H), 2.05–2.19 (m, 4H), 0.92 (s, 9H); 13C
NMR d 147.2, 145.0, 128.3, 117.4, 34.7, 33.1, 31.6, 29.1, 27.5.
4.2.38. 4-Methylene-1-(40-methylpent-3-enyl)-cyclo-
hexene and 5-methylene-1-(40-methylpent-3-enyl)-cyclo-
hexene (46a,b) [Table 1, entry 17]. A solution of potassium
tert-butoxide (1 M in THF, 6.3 mL, 6.3 mmol) was added
dropwise to a solution of 45a,b (830 mg, 3.0 mmol) in THF
(15 mL). The mixture was refluxed for 1 h, quenched with
NH4Cl solution, concentrated in vacuo, and the residue
taken up in ether (30 mL) and water (30 mL). The layers
were separated and the aqueous layer was extracted with
ether (3£40 mL). The combined ether layers were washed
with water (3£20 mL) and dried (MgSO4), concentrated in
vacuo and the residue chromatographed (pentane) yielding
4.2.41. Trichloro(methylsulfonyl)methane (49). Dimethyl
sulfone (1.5 g, 15.9 mmol) and SO2Cl2 (150 mL) were
placed in a photoreactor fitted with a Hanovia 450 W UV
lamp, wrapped with nichrome heating wire, and containing
at the bottom a gas bubbling tube and topped by a
condenser. The mixture was electrically heated to a gentle
reflux as Cl2 was slowly introduced. The refluxing solution
was irradiated for 2.5 h while monitoring TLC. The mixture
was then concentrated in vacuo, collecting the SO2Cl2 for
further use. The residue was chromatographed (5:1 hexane/
EtOAc) giving known 4918a as colorless crystals (2.86 g,
91%), mp 163–165 8C; 1H NMR d 3.35 (s, 3H); 13C NMR d
103.1, 33.4.
1
2.54:1 46a/46b (476 mg, 90%) as a colorless oil; 46a: H
NMR d 5.34 (br, 1H), 5.09 (t, J¼6.9 Hz, 1H), 4.71 (s, 2H),
2.75 (br, 2H), 2.31–1.92 (m, 8H), 1.67 (s, 3H), 1.58 (s, 3H);
13C NMR d 146.3, 137.8, 131.4, 124.3, 119.8, 107.2, 37.6,
33.5, 31.9, 30.8, 26.5, 25.7, 17.7; 46b: 1H NMR d 5.43 (br,
1H), 5.09 (t, J¼6.9 Hz, 1H), 4.71 (s, 2H), 2.68 (br, 2H),
2.31–1.92 (m, 8H), 1.67 (s, 3H), 1.58 (s, 3H); 13C NMR d
146.5, 137.1, 131.5, 124.3, 120.6, 107.1, 37.4, 36.9, 31.9,
31.6, 27.4, 26.4, 17.7; EI GC–MS m/z 176 (Mþ, 9%), 107
(26%), 91 (64%), 79 (45%), 69 (100%). The structure of the
compound was established by heating a portion of 46a,b
(190 mg, 1.08 mmol) with sulfur (34.5 mg, 1.08 mmol) at
200 8C for 12 h. Chromatography (hexanes0) of the product
gave as the major product 4-methyl-1-(4 -methylpent-30-
enyl)benzene (46c; 50 mg, 26%) which could be identified
by the simplicity of its 1H and 13C NMR spectra, compared
to the spectra expected for the meta isomer; 1H NMR d 7.08
(s, 4H), 5.19 (m, 1H), 2.55–2.62 (m, 2H), 2.31 (s, 3H),
2.35–2.05 (m, 2H), 1.69 (s, 3H), 1.58 (s, 3H); 13C NMR d
139.4, 135.1, 132.1, 129.0, 128.2, 123.9, 35.8, 30.2, 25.8,
21.1, 17.8.
4.2.42. 4-[(Dichloromethyl)sulfonyl]-1,2-dimethylcyclo-
hexene (50) [Table 1, entry 19]. A solution of 6 (1.0 g,
5.7 mmol) and 2,3-dimethylbuta-1,3-diene (1.0 g, 11.4 mmol)
in toluene (2 mL) was heated to 100 8C in a sealed tube
overnight, the mixture concentrated in vacuo and chro-
matographed (5:1 hexane/ethyl acetate) giving 50 (1.36 g,
1
93%) as colorless crystals, mp 71–72 8C; H NMR d 6.28
(s, 1H), 3.70–3.82 (m, 1H), 2.47 (t, J¼13.2 Hz, 1H), 2.20–
2.32 (m, 2H), 2.10–2.20 (m, 2H), 1.80–1.90 (m, 1H), 1.64
(s, 3H), 1.61 (s, 3H); 13C NMR d 126.0, 122.0, 55.6, 30.2,
19.0, 18.7; IR (neat): 777 (CCl2), 1140, 1332 (SO2), 1643,
1659 cm21 (CvC). Anal. Calcd for C9H14Cl2O2S: C,
42.03; H, 5.49. Found C, 42.21; H, 5.16.
4.2.43. 4-(Dichloromethylene)-1,2-dimethylcyclohexene
(51) [Table 1, entry 19]. A solution of 50 (300 mg,

E. Block et al. / Tetrahedron 60 (2004) 7525–7541
7539
1.17 mmol) and MeSO2CCl3 (300 mg, 1.62 mmol) in THF
(12 mL) was cooled to 23 8C under Ar. A solution of
KOtBu in THF (1 M, 2.34 mL, 2.34 mmol) was added
dropwise. The reaction mixture was stirred for 1 h at 0 8C
and was quenched with saturated aqueous NH4Cl solution.
The mixture was extracted with ether (2£20 mL). The
combined ether layers were dried, concentrated in vacuo
and chromatographed (hexane) to give the title compound
(566 mg, 2.0 mmol) and 49 (742 mg, 4.0 mmol) in THF
(15 mL) was cooled to 0 8C under Ar. A solution of KOtBu
in THF (1 M, 4.0 mL, 4.0 mmol) was added dropwise. The
reaction mixture was stirred for 1 h at 0 8C and was
quenched with saturated aqueous NH4Cl. The mixture was
extracted with ether (2£20 mL), dried, concentrated in
vacuo and chromatographed (hexane) yielding 55 (150 mg,
1
65%) as a colorless oil; H NMR d 2.79 (s, 2H), 2.51 (t,
1
(160 mg, 72%) as a colorless oil; H NMR d 2.85 (s, 2H),
J¼6.5 Hz, 2H), 2.02 (t, J¼6.5 Hz, 2H), 1.83–1.88 (m, 4H),
1.59–1.63 (m, 4H); 13C NMR d 135.5, 128.4, 125.7, 111.6,
35.7, 30.4, 29.9, 29.8, 29.7, 28.5, 22.9; EI MS: m/z 218
(Mþþ2, 62), 216 (Mþ, 93), 181 (100), 145 (80), 117 (30),
91 (55); IR (neat): 715 (CCl2), 1643, 1664 cm21 (CvC).
2.50 (t, J¼6.5 Hz, 2H), 2.09 (t, J¼5.5 Hz, 2H), 1.66 (s, 6H);
13C NMR d 135.7, 126.1, 123.3, 111.5, 36.7, 31.6, 29.7,
28.7, 18.7; EI MS m/z 192 (Mþþ2, 63), 190 (Mþ, 99), 177
(50), 175 (81), 155 (76), 139 (66), 119 (96), 91 (100), 77
(83), 51 (63); IR (neat): 1622 cm21 (CvC).
4.2.48. Chloromethylene-1,2,3,4,5,6,7,8-octahydro-
naphthalene (56) [Table 1, entry 22]. To a solution of 54
(283 mg, 1.0 mmol) in 60 mL of THF KOt-Bu in THF (1 M,
1.5 mL, 1.5 mmol) was added dropwise. The mixture was
stirred at 20 8C for 2 h and then warmed to 55 8C, and stirred
for an additional 8 h. The mixture was quenched with
saturated aqueous NH4Cl solution, extracted with ether
(2£20 mL), and the organic phase was dried, concentrated
in vacuo and chromatographed (hexane) to afford a brown
oil which by GC–MS consists of a 1:10:1 42/56/55 mixture
(120 mg, 66%).
4.2.44. 5-[(Dichloromethyl)sulfonyl]bicyclo[2.2.2]oct-2-
ene (52) [Table 1, entry 20]. A mixture of cyclohexa-1,3-
diene (800 mg mL, 10 mmol) and 6 (2.6 g, 15 mmol) in
toluene (5 mL) was heated in a sealed tube at 120–130 8C
for 12 h. The product was concentrated in vacuo and
chromatographed (5:1 hexane/EtOAc) yielding 52 (2.34 g,
92%) as colorless crystals, mp 121–122 8C which by NMR
was found to be a 3:1 endo/exo mixture; 1H NMR d 6.41 (t,
J¼6.8 Hz, 1H), 6.27 (t, J¼6.8 Hz, 1H), 6.10 (s, 1H), 3.80–
3.85 (m, 1H), 3.20–3.3 (m, 1H), 2.70–2.80 (m, 1H), 1.90–
2.20 (m, 2H), 1.55–1.67 (m, 2H), 1.31–1.43 (m, 2H); 13C
NMR d 135.4, 130.1, 78.2, 57.9, 30.0, 29.9, 29.3, 25.7, 23.0;
IR (CH2Cl2) 1147, 1336 cm21 (SO2). Anal. Calcd for
C9H12Cl2O2S: C, 42.36; H, 4.74. Found: C, 42.41; H, 5.10.
4.2.49. 5-exo-6-endo-Bis[(chloromethyl)sulfonyl]bi-
cyclo[2.2.1]hept-2-ene (57). Freshly distilled cyclopenta-
diene (0.21 mL, 2.6 mmol) was added to a suspension of
(E)-7 (0.33 g, 1.3 mmol) in CH2Cl2 (4 mL) and the reaction
mixture was stirred at room temperature until a colorless
clear solution was obtained (ca. 10 min). Concentration in
vacuo followed by chromatography of the residue afforded
57 as a colorless solid (0.35 g, 83%), mp 144–145 8C; IR
(film) 1322 (SO2), 1149 (SO2), 1121 (SO2) cm21; 1H NMR
d 6.44 (dd, J¼3.00, 5.4 Hz, 1H), 6.39 (dd, J¼3.00, 5.4 Hz,
1H), 4.75 (d, J¼8.4 Hz, 1H), 4.71 (d, J¼8.4 Hz, 1H), 4.57
(d, J¼12.6 Hz, 1H), 4.44 (dd, J¼3.3, 5.1 Hz, 1H), 4.42 (d,
J¼12.6 Hz, 1H), 3.73 (dd, J¼2.1, 5.1 Hz, 1H), 3.52 (m, 2H),
2.03 and 1.71 (ABq, J¼9.6 Hz, 2H); 13C NMR d 136.8,
136.2, 61.1, 60.5, 56.4, 56.2, 47.6, 46.6, 45.2. Anal. Calcd
for C9H12Cl2O4S2: C, 33.86; H, 3.79. Found: C, 33.51;
H, 3.09.
4.2.45. 5-(Dichloromethylene)bicyclo[2.2.2]oct-2-ene
(53) [Table 1, entry 20]. Compound 52 (255 mg,
1.0 mmol) and 49 (296 mg, 1.5 mmol) in THF (12 mL)
were cooled to 23 8C under Ar and KOt-Bu (1 M in THF,
2.0 mL, 2.0 mmol) was added dropwise. The reaction
mixture was stirred for 1 h at 0 8C, quenched with saturated
aqueous NH4Cl solution, extracted with ether (2£20 mL),
the combined ether layers dried, concentrated in vacuo and
the residue chromatographed (hexane) to yield 53 (136 mg,
72%) as a colorless oil; 1H NMR d 6.39 (t, J¼6.7 Hz, 1H),
6.26 (t, J¼6.7 Hz, 1H), 3.63–3.65 (m, 1H), 2.80–2.82 (m,
1H), 2.06–2.22 (m, 2H), 1.50–1.67 (m, 2H), 1.34–1.46 (m,
2H); 13C NMR d 140.0, 135.8, 131.1, 36.9, 31.2, 29.7, 24.6,
24.2; EI MS: m/z 190 (Mþþ2, 10), 188 (Mþ, 16), 160 (54),
125 (100); IR (neat): 3048, 1626, 1444, 899 (CvC), 1463,
709 cm21 (CCl2).
4.2.50. 5-endo-6-endo-Bis[(chloromethyl)sulfonyl]bi-
cyclo[2.2.1]hept-2-ene (58). Freshly distilled cyclopenta-
diene (0.1 mL, 1.2 mmol) was added to a suspension of
(Z)-7 (0.15 g, 0.6 mmol) in CH2Cl2 (4 mL) and the reaction
mixture was stirred at room temperature until a clear
colorless solution was obtained (ca. 10 min). The product
was concentrated in vacuo and the residue chromatographed
(hexanes/EtOAc 5:1) affording 58 as a colorless solid
(0.16 g, 84%), mp 184–186 8C; IR (film) 1331 (SO2), 1152
4.2.46. 2-[(Dichloromethyl)sulfonyl]-1,2,3,4,5,6,7,8-octa-
hydronaphthalene (54) [Table 1, entry 21]. A solution of
6 (1.0 g, 5.7 mmol) and 1,2-bis(methylene)cyclohexane
(1.23 g, 11.4 mmol) in toluene (2 mL) was heated to
100 8C in a sealed tube overnight. The mixture was
concentrated in vacuo and chromatographed (5:1 hexane/
EtOAc) yielding 54 (1.52 g, 94%) as colorless crystals, mp
91–93 8C; 1H NMR d 6.27 (s, 1H), 3.75–3.85 (m, 1H), 2.42
(t, J¼12.6 Hz, 1H), 2.15–2.30 (m, 2H), 2.03–2.11 (m, 2H),
1.80–1.90 (m, 5H), 1.62–1.75 (m, 2H), 1.40–1.52 (m, 2H);
13C NMR d 128.4, 124.5, 55.5, 30.0, 29.8, 29.1, 22.8, 21.8;
IR (CHCl3) 1140, 1322 cm21 (SO2). Anal. Calcd for
C11H16Cl2O2S: C, 46.65; H, 5.69. Found: C, 46.81; H, 5.32.
1
(SO2) cm21; H NMR (CD3COCD3) d 6.50 (m, 2H), 5.14
and 4.98 (ABq, J¼12.6 Hz, 4H), 4.79 (m, 2H), 3.82 (m, 2H),
1.76 and 1.65 (ABq, J¼9.0 Hz, 2H); 13C NMR (CD3COCD3)
d 130.9, 60.3, 53.4, 43.7, 42.8. Anal. Calcd for
C9H12Cl2O4S2: C, 33.86; H, 3.79. Found: C, 33.72; H, 3.48.
4.2.51. 2-[(Chloromethyl)sulfonyl]bicyclo[2.2.1]hepta-
2,5-diene (59). Method 1. A solution of KOt-Bu in THF
(1.88 mL, 1.88 mmol, 1 M) was added to 57 (0.3 g,
0.94 mmol) in THF (10 mL) at 0 8C. The reaction mixture
4.2.47. 2-(Dichloromethylene)-1,2,3,4,5,6,7,8-octahydro-
naphthalene (55) [Table 1, entry 21]. A solution of 54

7540
E. Block et al. / Tetrahedron 60 (2004) 7525–7541
was stirred at room temperature for 1 h and the reaction was
quenched with NH4Cl solution. The mixture was extracted
with ether (2£20 mL), washed with brine (2£20 ml), dried,
concentrated in vacuo and the residue chromatographed
(hexanes/EtOAc 5:1, Rf¼0.31) yielding 59 as a colorless oil
(40 mg, 2%): 1H NMR d 7.84 (d, J¼3.4 Hz, 1H), 6.97 (dd,
J¼3.2, 5.0 Hz, 1H), 6.79 (dd, J¼3.2, 5.0 Hz, 1H), 4.40 and
4.36 (d, J¼6.6 Hz, 2H), 3.94 (m, 1H), 3.87 (m, 1H), 2.35
and 2.23 (ABq, J¼7.2 Hz, 2H); 13C NMR d 161.5, 153.2,
142.9, 141.8, 75.4, 56.6, 52.3, 51.8; IR (neat) 1319,
1161 cm21 (SO2); EI-MS m/z: 204 (Mþ, 14%), 154
(28%), 91 (100%), 65 (98%). Method 2. A solution of
KOt-Bu in THF (0.62 mL, 0.62 mmol, 1 M) was added to 58
(0.1 g, 0.31 mmol) in THF (6 mL) at 0 8C. The reaction
mixture was stirred at room temperature for 1 h, quenched
with NH4Cl solution, extracted with ether (2£20 mL),
washed with brine (2£20 ml), dried, concentrated in vacuo
and the residue chromatographed (hexanes/EtOAc 5:1,
Rf¼0.31) yielding the title compound (10 mg, 16%).
Method 3. [(Chloromethyl)sulfonyl]ethyne (8) (139 mg,
1.0 mmol) was placed in a 50 mL flask and cooled to 0 8C.
Cyclopenta-1,3-diene (200 mg, 3.0 mmol) was added, then
the mixture was stirred for 6 h at 0 8C. The reaction mixture
was chromatographed (hexane/ethyl acetate¼5:1) to yield
59 (186 mg, 91%) as a colorless oil. Compound 59
decomposes upon standing at room temperature.
4.2.54. (E)-2-Buta-1,3-dienyl-6,6-dimethylbicyclo[3.3.1]-
hept-2-ene (63). A solution of KOt-Bu in THF (3.1 mL,
3.1 mmol, 1 M) was added to b-pinene adduct 61 (0.57 g,
1.46 mmol) in THF (30 mL) at 0 8C. The reaction mixture
was refluxed for 1 h, quenched with NH4Cl solution, and
extracted with CHCl3 (5£30 mL). The organic layer was
washed with brine (2£30 mL) and dried, concentrated in
vacuo and the residue chromatographed (hexanes) yielding
1
63 (30 mg, 12%) as a colorless oil: H NMR d 6.39 (dd,
J¼9.9, 16.8 Hz, 1H), 6.23 (d, J¼15.6 Hz, 1H), 6.01 (d,
J¼15.6 Hz, 1H), 5.58 (s, 1H), 5.16 (d, J¼16.8 Hz, 1H), 5.01
(d, J¼9.9 Hz, 1H), 2.56 (m, 1H), 2.45–2.28 (m, 3H), 2.01
(m, 1H), 1.32 (s, 3H), 1.12 (d, J¼8.7 Hz, 1H), 0.78 (s, 3H);
13C NMR d 146.5, 137.7, 134.6, 125.9, 125.5, 115.9, 41.0,
37.8, 32.2, 31.4, 29.7, 26.4, 21.1; GC/MS (rel. intensity) m/z
174 (Mþ, 10), 131 (44), 91 (100), 77 (41); UV (CH2Cl2)
lmax 278 nm.
Acknowledgements
This work was supported by NSF (CHE-9906566) and the
Petroleum Research Fund, administered by the American
Chemical Society.
4.2.52. 2-{20,30-Bis[(chloromethyl)sulfonyl]propyl}-6,6-
dimethylbicyclo[3.1.1]hept-2-ene (61). A mixture of
(E)-7 (0.57 g, 2.25 mmol) and b-pinene (0.64 g,
4.67 mmol) in toluene (1.5 mL) were placed in a sealed
tube and flushed with argon. The white slurry was heated at
135 8C for 1.5 h and then concentrated in vacuo at 60 8C and
the residue chromatographed (hexanes/EtOAc 5:1) yielding
61 as a colorless solid (0.63 g, 72%), mp 108–110 8C; IR
(film) 1323 (SO2), 1122 (SO2) cm21; 1H NMR d 5.09–5.51
(m, 1H), 4.63 and 4.77 (ABq, J¼12.6 Hz, 2H), 4.45 and 4.77
(ABq, J¼12.6 Hz, 2H), 4.01–4.13 (m, 2H), 3.29–3.35
(m, 1H), 2.74–2.82 (m, 1H), 2.40–2.50 (m, 2H), 2.26–2.28
(m, 2H), 2.01–2.12 (m, 2H), 1.88 (s, 3H), 1.15 (d, J¼9 Hz,
1H), 0.83 (s, 3H); 13C NMR d 141.9, 123.1, 57.2, 55.9, 52.0,
47.6, 45.3, 40.3, 38.2, 36.5, 31.7, 31.5, 26.0, 21.1. Anal.
Calcd for C9H12Cl2O4S2: C, 43.29; H, 5.70. Found: C,
43.39; H, 5.78.
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