A new synthesis of alkylidenecyclopropanes by the Julia-Lythgoe-type olefination using sulfones and sulfoxides

Article abstract of DOI:10.1055/s-2004-822899

The first use of the Julia-Lythgoe-type olefination with cyclopropylsulfones and cyclopropylsulfoxides for the synthesis of alkylidenecyclopropanes is reported.

Full text of DOI:10.1055/s-2004-822899

1064
LETTER
A New Synthesis of Alkylidenecyclopropanes by the Julia–Lythgoe-type
Olefination Using Sulfones and Sulfoxides
A
New Synthesis
o
n
f
A
lkylidene
g
cyclopropan
e
es la M. Bernard,* Angelo Frongia, Pier Paolo Piras,* Francesco Secci
Dipartimento di Scienze Chimiche, Università di Cagliari, Complesso Universitario di Monserrato, S.S. 554, Bivio per Sestu,
09042 Monserrato (Cagliari), Italy
Fax +39(070)6754388; E-mail: pppiras@unica.it
Received 19 January 2004
Dedicated to Jacques Salaun, Orsay-Paris, on the occasion of his 65th birthday.
transition-metal catalyzed reactions like silaboration,15
Abstract: The first use of the Julia–Lythgoe-type olefination with
silylcyanation,16 hydrosilylation,17 diboration,18 hydroam-
cyclopropylsulfones and cyclopropylsulfoxides for the synthesis of
alkylidenecyclopropanes is reported.
ination,19 hydroalkoxylation,20 and hydrocarbonation.21
On the other hand, despite their high level of strain they
Key words: olefination, carbocycles, sulfones, sulfoxides, alky-
are very often stable and their carbon skeleton can be
lidenecyclopropanes
found in several natural products that display relevant
biological properties.22
Among the several synthetic strategies reported we are
particularly interested in the methods that involve 1,2-
elimination from twofold functionally substituted cyclo-
propane derivatives.23a–f As a matter of fact, in continua-
tion of our studies of the chemistry of alkylidene-
cyclopropanes,14 we recently reported24 their synthesis by
using the Ramberg–Backlund reaction. Now here we
report our successful use of the Julia–Lythgoe-type olefi-
nation, both in its sulfone25 and sulfoxide26 version for the
synthesis of alkylidenecyclopropanes.27
Methylene and alkylidenecyclopropanes are particularly
interesting molecules due to their unique reactivity com-
ing from their high level of strain, that have served as use-
ful building blocks in organic synthesis.1 They undergo
Ni(0)- or Pd(0)-catalyzed reaction with alkenes and
alkynes for the synthesis of five-membered rings,2a,3–7
ring opening with palladium chloride to give p-allyl palla-
dium complexes,8 1,3-dipolar cycloaddition2b,9 and are
suitable precursors of cyclobutanones10–13 and cyclobu-
tanols.14 More recently they have been used in several
Scheme 1 a) n-BuLi, THF, RCHO, 0 °C to r.t.; b) MCPBA, CH2Cl2, 0 °C; c) MCPBA, CH2Cl2, –20 °C; d) Ac2O, DMAP, CH2Cl2, 0 °C to
r.t.; e) Different conditions: n-BuLi, THF, TsCl, 0 °C to r.t.; BzCl, Et3N, DMAP, 0 °C to r.t.; SOCl2, CCl4, reflux; f) Na/Hg 10%, THF–MeOH,
–20 °C or Mg, HgCl2 cat., anhyd EtOH, r.t.; g) n-BuLi, THF, –78 °C.
SYNLETT 2004, No. 6, pp 1064–1068
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Advanced online publication: 25.03.2004
DOI: 10.1055/s-2004-822899; Art ID: G02404ST
© Georg Thieme Verlag Stuttgart · New York

LETTER
A New Synthesis of Alkylidenecyclopropanes
1065
For this purpose, the cyclopropyl carbinols 1a–d, pre- Next we checked the possibility of synthesizing alkyl-
pared from reaction of the lithium cyclopropylphenyl idenecyclopropanes carrying a substituent on the cyclo-
sulfide28 with the corresponding aldehydes, were trans- propyl ring. This target was achieved according to the
formed into the corresponding sulfones 2a–d and the sul- sequence of reactions reported in the Scheme 2. The de-
foxides 8a,b,d by oxidation with MCPBA at different rivatives 10a–c obtained by Knoevenagel condensation of
temperatures (Scheme 1).
phenylthioacetone with the corresponding aldehyde, were
cyclopropanated as usual with the Corey ylide to give
11a–c that were reduced to the corresponding alcohols
12a–c.
By transformation of their alcoholic function into differ-
ent X groups (Ac, Ts, Cl, Bz), the cyclopropyl sulfones
2a–d led to the derivatives 3a–6a, 3b–d, 4b, which were
treated with Na/Hg in THF–MeOH at –20 °C or with Mg/ Transformation of 12a,b into the sulfones 13a,b and reac-
HgCl2 (cat.) in anhydrous EtOH at room temperature. tion of these latter derivatives with Ac2O gave the acetoxy
Good yields of 7a,b29 were obtained with the first method sulfones 14a,b which, after treatment with sodium amal-
(Na/Hg) when the leaving group was the tosylate, and gam, led to the methylcyclopropilidene 15a,b (yields 56%
with the second method (Mg/HgCl2) when the leaving and 65% respectively) as a 60:40 mixture of geometric
group was the chloride. On the other hand 7c30 was ob- isomers, accompanied by 20% of 16a,b as a 65:35 and
tained in low yields (Table 1).
50:50 syn/anti-mixture, respectively, which arise from
desulfonation and deacetylation reaction. Unexpectedly,
the cyclopropylsulfoxide 18c, obtained by oxidation and
acetylation of 12c, when reacted with n-BuLi, gave only
the cyclopropylsulfoxide alcohol 17c through a deacetyla-
tion reaction. The reason for this failure is now being in-
vestigated as well as the examination of substrates
carrying a tertiary leaving group, which, from preliminary
experiments, appear to be unreactive under our experi-
mental conditions.
The sulfoxides 8a,b,d were transformed into the corre-
sponding acetates 9a,b,d that were treated with n-BuLi to
give reasonable to good yields of 7a,b and 7d14 with no
traces of side products, coming from simple desulfonyla-
tion and deacetylation, which were formed with the other
methods (Table 1). By comparing the yields of entries 1,
2, 7, 8, 11 and 12–14 (Table 1) it can be seen that better
results were obtained by using the sulfoxide version of the
Julia–Lithgoe olefination which, moreover, avoids the use
of the polluting sodium amalgam.
Table 1 Synthesis of Alkylidenecyclopropanes 7a–d from Cyclopropylsulfones 3a–6a, 3b–d, 4b and Cyclopropylsulfoxides 9a,b,d
Entry
Starting Material
R
X
Reagent
Na/Hg
Yield (%)
7a (53)
7a (53)
7a (35)
7a (75)
7a (30)
7a (95)
7b (50)
7b (48)
7b (89)
7c (26)
7d (0)
1
2
3a
3a
4a
5a
6a
6a
3b
3b
4b
3c
3d
p-Me-C6H4
p-Me-C6H4
p-Me-C6H4
p-Me-C6H4
p-Me-C6H4
p-Me-C6H4
(CH2)9CH3
(CH2)9CH3
(CH2)9CH3
CH=CH2
-OCOCH3
-OCOCH3
-OCOC6H4
-OTs
Mg/HgCl2
Na/Hg
3
4
Na/Hg
5
-Cl
Na/Hg
6
-Cl
Mg/HgCl2
Na/Hg
7
-OCOCH3
-OCOCH3
-Cl
8
Mg/HgCl2
Mg/HgCl2
Na/Hg
9
10
11
-OCOCH3
-OCOCH3
Na/Hg
12
13
14
9a
9b
9d
p-Me-C6H4
-OCOCH3
-OCOCH3
-OCOCH3
n-BuLi
n-BuLi
n-BuLi
7a (76)
7b (60)
7d (42)
(CH2)9CH3
Synlett 2004, No. 6, 1064–1068 © Thieme Stuttgart · New York

1066
A. M. Bernard et al.
LETTER
Scheme 2 a) Trimethylsulfoxonium iodide, NaH, DMSO, r.t. to 50 °C; b) LiAlH4, THF, –30 °C; c) MCPBA, CH2Cl2, 0 °C; d) Ac2O, DMAP,
CH2Cl2, 0 °Cr.t.; e) Na/Hg 10%, THF–MeOH, –20 °C; f) MCPBA, CH2Cl2, –20 °C; g) n-BuLi, THF, –78 °C.
(9) Pisaneschi, F.; Cordero, F. M.; Goti, A.; Paugam, R.;
Ollivier, J.; Brandi, A.; Salaun, J. Tetrahedron: Asymmetry
2000, 11, 897.
(10) Salaun, J. Rearrangements Involving the Cyclopropyl
Group, In The Chemistry of the Cyclopropyl Group;
Rappoport, Z., Ed.; Wiley: New York, 1987, 809.
(11) Salaun, J.; Conia, J. M. J. Chem. Soc., Chem. Commun.
1971, 1579.
(12) Salaun, J.; Champion, J.; Conia, J. M. Org. Synth. 1977, 57,
36.
(13) Salaun, J. Top. Curr. Chem. 1988, 144, 1.
(14) Bernard, A. M.; Floris, C.; Frongia, A.; Piras, P. P.
Tetrahedron 2000, 56, 4555.
In conclusion we have reported a new method for the syn-
thesis of alkylidenecyclopropanes in moderate to good
yields that compares favorably with the already published
methods. The easy access to cyclopropanes carrying a
sulfur atom makes the method particularly versatile and
substituents can be easily introduced on the cyclopropane
ring.
Acknowledgment
Financial support from the Ministero dell’Università e della Ricerca
Scientifica e Tecnologica, Rome, and by the University of Cagliari
[National Projects ‘Stereoselezione in Sintesi Organica. Metodolo-
gie ed Applicazioni’ (PRIN) and ‘Design, synthesis and biological
and pharmacological evaluation of organic molecules as innovative
drugs’ (FIRB)] is gratefully acknowledged.
(15) Suginome, M.; Matsuda, T.; Ito, Y. J. Am. Chem. Soc. 2000,
122, 11015.
(16) Ishiyama, T.; Momota, S.; Miyaura, N. Synlett 1999, 1790.
(17) Bessmertnykh, A. G.; Blinov, K. A.; Grishin, Y. K.;
Donskaya, N. A.; Tveritinova, E. V.; Yurieva, N. M.;
Beletskaya, I. P. J. Org. Chem. 1997, 62, 6069.
(18) Chatani, N.; Takeyasu, T.; Hanafusa, T. Tetrahedron Lett.
1988, 29, 3979.
References
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(22) For the aminoacid hypoglycine see: (a) Hassall, C. H.;
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Tetrahedron 1994, 50, 12015. (d) For the
(4) Ohta, T.; Takaya, H. In Comprehensive Organic Synthesis,
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Org. Chem. 1989, 54, 6056.
methylenecyclopropyl glycine see: Grey, D. O.; Fowden, L.
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derivative, isolated from the fermentation broth of
Synlett 2004, No. 6, 1064–1068 © Thieme Stuttgart · New York

LETTER
Cytophaga Johnsonii, that has antibiotic activity against a
A New Synthesis of Alkylidenecyclopropanes
1067
101(100), 91(16). Anal. Calcd for C15H20O3S: C, 64.26; H,
7.19; S, 11.43. Found: C, 64.41; H, 7.26; S, 11.39. Major
isomer. Yellow oil. Yield 40%. [a]D27 –25.74 (c 4.00,
CHCl3). IR (neat): 3430 cm–1. 1H NMR (CDCl3): d = 0.93–
1.28 (m, 4 H), 1.31 (s, 3 H), 1.38 (s, 3 H), 2.65 (br s, 1 H),
3.51 (d, 1 H, J = 5.7 Hz), 3.91 (dd, 1 H, J = 6.3 Hz and
J = 8.4 Hz), 4.04 (dd, 1 H, J = 8.4 Hz and 6.3 Hz), 4.31 (q,
1 H, J = 6.3 Hz), 7.12–7.48 (m, 5 H). 13C NMR (CDCl3): d
= 13.3, 13.6, 25.1, 26.1, 27.3, 65.5, 75.0, 78.7, 108.5, 125.6,
128.1, 128.5, 136.0. MS: m/z (%) = 280 (14) [M+], 265 (20),
204 (4), 191(23), 179 (20), 149 (14), 101(100), 91(15). Anal.
Calcd for C15H20O3S: C, 64.26; H, 7.19; S, 11.43. Found: C,
64.36; H, 7.28; S, 11.34.
Sulfoxide 8d: (Obtained by oxidation of the minor isomer of
1d): Colorless oil. Yield 90%. Spectral data refer to a 70:30
mixture of two inseparable diastereoisomers. IR (neat):
1040, 3430 cm–1. 1H NMR (CDCl3): d = 0.98 (s, 3 H), 1.18–
1.57 (m, 8 H), 1.22 (s, 3 H), 1.27 (s, 3 H), 1.43 (s, 3 H), 1.84
(s, 2 H), 3.64–4.29 (m, 8 H), 7.51–7.70 (m, 10 H). Major
isomer: MS: m/z (%) = 281 (39) [M+ – 15], 221 (18), 195
(100), 153 (77), 125 (34), 109 (18), 101(59), 95 (64), 77
(25). Minor isomer: MS: m/z (%) = 281 (34) [M+ – 15], 221
(18), 195 (100), 153 (77), 125 (40), 109 (21), 101 (86), 95
(98), 77 (30). Anal. Calcd for C15H20O4S: C, 60.79; H, 6.80;
S, 10.82. Found: C, 60.64; H, 6.68; S, 10.61.
Acetate 9d: Yield 90%. A 70:30 mixture of two inseparable
diastereoisomers: IR (neat): 1060, 1740 cm–1. Major isomer:
1H NMR (CDCl3): d = 1.20–1.36 (m, 4 H), 1.30 (s, 3 H,),
1.34 (s, 3 H), 1.84 (s, 3 H), 3.73 (dd, 1 H, J = 6.3 Hz and
J = 8.7 Hz), 4.07 (dd, 1 H, J = 6.3 Hz and J = 8.7 Hz), 4.48
(q, 1 H, J = 6.3 Hz), 4.85 (d, 1 H, J = 6.9 Hz), 7.47–7.70 (m,
5 H). Minor isomer: 1H NMR (CDCl3): d = 1.20–1.36 (m, 4
H), 1.28, (s, 3 H), 1.32 (s, 3 H), 1.83 (s, 3 H), 3.78 (dd, 1 H,
J = 6.3 Hz and J = 8.7 Hz), 4.02 (dd, 1 H, J = 6.3 Hz and
J = 8.7 Hz), 4.39 (q, 1 H, J = 6.3 Hz), 5.03 (d, 1 H, J = 6.3
Hz), 7.47–7.70 (m, 5 H). MS (identical for the two isomers):
m/z (%) = 323 (7) [M+ – 15], 281 (6), 207 (43), 191 (12), 153
(27), 125 (13), 95 (59), 43 (100). Anal. Calcd for C17H22O5S:
C, 60.34; H, 6.55; S, 9.47. Found: C, 60.44; H, 6.78; S, 9.61.
Methylcyclopropilidene 15b: Colorless oil. Yield 65%. Data
worked out from the unseparable 60:40 E/Z-mixture: 1H
NMR (CDCl3): d = 1.05–1.12 (m, 2 H), 1.63–1.70 (m, 2 H),
1.76–1.80 (m, 3 H, E-isomer), 1.84–1.89 (m, 3 H, Z-isomer),
2.29 (s, 3 H, Z-isomer), 2.30 (s, 3 H, E-isomer), 2.52–2.55
(m, 2 H), 5.91–5.95 (m, 2 H), 6.98–7.08 (m, 8 H). 13C NMR
(CDCl3): d = 13.3, 15.0, 16.8, 17.0, 19.2, 19.7, 19.8, 20.9,
21.0, 114.3, 114.5, 126.1, 126.3, 128.9, 129.0, 135.0, 135.1,
139.2, 139.5. MS (identical for the two isomers): m/z (%) =
158 (12) [M+], 143 (100), 128 (65), 115 (25), 91 (7), 77 (12).
Anal. Calcd for C12H14: C, 91.08; H, 8.92. Found: C, 91.15;
H, 8.98.
Compound 16b: A 50:50 mixture of two E-diastereoisomers
(syn + anti). Colorless oil. Yield 20%. IR (neat): 3400 cm–1.
anti-Diastereoisomer: 1H NMR (CDCl3): d = 0.85–0.90 (m,
2 H), 1.24–1.26 (m, 1 H), 1.34 (d, 3 H, J = 5.7 Hz), 1.57 (br
s, 1 H), 1.75–1.78 (m, 1 H), 2.30 (s, 3 H), 3.36 (q, 1 H,
J = 5.7 Hz), 6.95–7.08 (m, 4 H). 13C NMR (CDCl3): d =
13.6, 20.9, 22.7, 30.6, 71.9, 76.6, 125.8, 129.0, 135.2, 139.3.
syn-Diastereoisomer: 1H NMR (CDCl3): d = 0.91–0.98 (m, 2
H), 1.20–1.22 (m, 1 H), 1.32 (d, 3 H, J = 5.7 Hz), 1.57 (br s,
1 H), 1.84–1.92 (m, 1 H), 2.30 (s, 3 H), 3.34 (q, 1 H, J = 5.7
Hz), 6.95–7.08 (m, 4 H). 13C NMR (CDCl3): d = 13.1, 20.4,
22.3, 30.6, 71.9, 76.6, 125.7, 129.0, 135.1, 139.4. MS
(identical for the two isomers): m/z (%) = 176 (5) [M+], 143
(21), 131 (40), 121 (96), 117 (100), 91 (55), 77 (20). Anal.
Calcd for C12H16O: C, 81.77; H, 9.15. Found: C, 81.65; H,
8.86.
few bacteria see: Evans, J. R.; Napier, E. J.; Fletton, R. A. J.
Antibiot. 1978, 31, 952.
(23) For some examples see: (a) Salaun, J.; Bennani, F.;
Compain, J. C.; Fadel, A.; Ollivier, J. J. Org. Chem. 1980,
45, 4129. (b) Cohen, T.; Sherbine, J. P.; Matz, J. R.;
Hutchins, R. R.; McHenry, B. M.; Willey, P. R. J. Am.
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(24) Bernard, A. M.; Frongia, A.; Piras, P. P. Synth. Commun.
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(25) (a) Julia, M.; Paris, J.-M. Tetrahedron Lett. 1973, 4833.
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2000, 56, 6223.
(27) Typical Procedure for the Reductive Elimination of the
Sulfones with Na/Hg.
To a stirred suspension of sodium amalgam (10%, 422 mg,
1.85 mmol) in THF (6 mL) and MeOH (2 mL) at –20 °C,
under Argon was added a solution of the appropriate
cyclopropylsulfone (0.37 mmol) in THF (2 mL). After 30
min at same temperature the reaction mixture was diluted
with Et2O, washed with brine, dried and concentrated in
vacuo. Chromatography with light petroleum-Et2O, (1:1)
yielded the corresponding alkylidenecyclopropanes.
Typical Procedure for the Reductive Elimination of the
Sulfones with Mg/HgCl2 cat.
A mixture of the cyclopropylsulfone (0.76 mmol), Mg
powder (54.7 mg, 2.28 mmol) and few crystals of HgCl2 in
dry EtOH (10 mL) was stirred for 1 h at r.t. The reaction
mixture was then poured into cold 0.5 N HCl and extracted
with Et2O. The organic layer was washed with sat. aq
NaHCO3, dried (Na2SO4), filtered and then concentrated in
vacuo to give the crude products which were purified as
above.
Typical Procedure for the Reductive Elimination of the
Sulfoxides with n-BuLi.
To a solution of n-BuLi (1.5 M in hexane, 1.6 mL, 2.4 mmol)
at –78 °C, under an argon atmosphere, a solution of the
cyclopropylsulfoxide (0.6 mmol) in THF (10 mL) was added
dropwise with stirring. After stirring for 5 min, the reaction
was quenched with sat. aq NH4Cl and the mixture was
extracted with Et2O. The organic layer, dried and
evaporated, gave the corresponding alkylidenecyclo-
propanes that were purified as above.
All new compounds have been fully characterized by 1H
NMR (300 MHz), 13C NMR (75.4 MHz), IR, GLC mass
spectra (70 eV) and elemental analyses.
Selected analytical data for some representative derivatives
are reported.
Cyclopropyl carbinol 1d: A 65:35 mixture of two
diastereoisomers. Minor isomer. White crystals, mp 58–
60 °C. Yield: 21%. [a]D25 +39.30 (c 3.89, CHCl3). IR (film):
3400 cm–1.1H NMR (CDCl3): d = 0.91–1.30 (m, 4 H), 1.34
(s, 3 H), 1.39 (s, 3 H), 2.62 (br s, 1 H), 3.49 (d, 1 H, J = 5.1
Hz), 3.78 (t, 1 H, J = 8.1 Hz), 4.04 (dd, 1 H, J = 8.1 Hz and
6.6 Hz), 4.43 (q, 1 H, J = 6.6 Hz), 7.12–7.46 (m, 5 H). 13
C
NMR (CDCl3): d = 11.3, 13.9, 25.2, 26.4, 26.8, 66.8, 73.4,
77.5, 109.1, 125.7, 128.1, 128.7, 136.1. MS: m/z (%) = 280
(13) [M+], 265 (15), 207(10), 191 (13), 178 (14), 149 (13),
Synlett 2004, No. 6, 1064–1068 © Thieme Stuttgart · New York

1068
A. M. Bernard et al.
LETTER
(30) For a more efficient preparation of the alkylidene-
(28) Cyclopropylphenyl sulfide is a rather expensive commercial
product, which can be conveniently prepared using cheap
starting materials: Tanaka, K.; Uneme, H.; Matsui, S.; Kaji,
A. Bull. Chem. Soc. Jpn. 1982, 55, 2965.
(29) (a) Salaun, J.; Hanack, M. J. Org.Chem. 1975, 40, 1994.
(b) Halazy, S.; Dumont, W.; Krief, A. Tetrahedron Lett.
1981, 22, 4737. (c) Krief, A.; Ronvaux, A.; Tuch, A. Bull.
Soc. Chim. Belg. 1997, 106, 699.
cyclopropane 7c see: (a) Zefirov, N. S.; Kozhushkov, S. I.;
Kuznetsova, T. S.; Lukin, K. A.; Kazimirchik, I. V. J. Org.
Chem. USSR (Engl. Transl.) 1988, 24, 605. (b) Meagher, T.
P.; Yet, L.; Hsiao, C.-N.; Shechter, H. J. Org. Chem. 1998,
63, 4181.
Synlett 2004, No. 6, 1064–1068 © Thieme Stuttgart · New York