1214
P. R. Blakemore et al.
PAPER
(Z,S)-2-[2-[5-(tert-Butyldimethylsilyloxy)-2-methylenecyclo-
hexylidene]ethylsulfanyl]benzothiazole (19)
(S,Z)-4-[(Benzothiazol-2-yl)sulfonyl]methyl-1-[(1,1-dimethyl-
ethyl)dimethylsilyl]oxy-3-vinylcyclohex-3-ene (20)
To a stirred solution of the A-ring dienol 7 (540 mg, 2.0 mmol),
PPh3 (630 mg, 2.4 mmol) and 2-sulfanylbenzothiazole (550 mg, 3.3
mmol) in anhyd THF (10 mL) at r.t. under N2 was added dropwise
neat diisopropyl azodicarboxylate (0.48 g, 2.4 mmol). The resultant
solution was stirred for 12 h and then concentrated in vacuo. The
crude residue was further purified via column chromatography
(eluting with 5% Et2O in hexanes) to yield the sulfide 19 (747 mg,
1.79 mmol, 89%) as a clear oil: [a]D = +36.9 (c = 1.04, CHCl3).
IR (film): n = 2929 (s), 2856 (s), 1472 (s), 1334 (s), 1252 (s), 1152
(s), 1097 (s), 1006 (m), 882 (m), 837 (s), 763 (s), 729 (m) cm–1.
1H NMR (360 MHz, CDCl3): d = 8.23 (1H, dm, J = 7.9 Hz), 7.99
(1H, dm, J = 8.4 Hz), 7.64 (1H, ddd, J = 8.2, 7.2, 1.4 Hz), 7.59 (1H,
ddd, J = 8.1, 7.2, 1.3 Hz), 6.50 (1H, dd, J = 17.1, 10.9 Hz), 5.01
(1H, d, J = 16.4 Hz), 4.79 (1H, d, J = 11.1 Hz), 4.42 (1H, d, J = 14.2
Hz), 4.33 (1H, d, J = 14.0 Hz), 3.97–3.90 (1H, m), 2.59–2.34 (3H,
m), 2.07 (1H, ddm, J = 17.2, 7.0 Hz), 1.84–1.75 (1H, m), 1.68–1.58
(1H, m), 0.89 (9H, s), 0.07 (3H, s), 0.06 (3H, s).
13C NMR (90 MHz, CDCl3): d = 165.4 (0), 153.0 (0), 137.7 (0),
136.7 (0), 133.1 (1), 128.1 (1), 127.8 (1), 125.6 (1), 122.3 (1), 121.9
(0), 114.8 (2), 67.1 (1), 58.8 (2), 35.3 (2), 31.5 (2), 30.1 (2), 26.0
(3C, 3), 18.3 (0), –4.4 (3), –4.5 (3).
IR (film): n = 2934 (s), 2855 (s), 1460 (s), 1428 (s), 1252 (m), 1092
(s), 997 (s), 902 (m), 869 (m), 836 (s), 774 (s), 755 (s), 726 (m) cm–1.
1H NMR (360 MHz, CDCl3): d = 7.88 (1H, dm, J = 8.2 Hz), 7.76
(1H, dm, J = 8.0 Hz), 7.42 (1H, ddd, J = 8.4, 7.3, 1.2 Hz), 7.30 (1H,
ddd, J = 8.1, 7.0, 1.2 Hz), 5.51 (1H, tm, J = 7.8 Hz), 5.06 (1H, br s),
4.87 (1H, br s), 4.19 (1H, dd, J = 12.8, 7.9 Hz), 4.11 (1H, ddd,
J = 12.8, 7.6, 1.1 Hz), 3.83 (1H, tt, J = 8.2, 3.7 Hz), 2.50–2.38 (2H,
m), 2.22 (1H, dd, J = 12.9, 8.1 Hz), 2.11 (1H, dddm, J = 14.4, 8.4,
4.4 Hz), 1.90–1.82 (1H, m), 1.62 (1H, dddd, J = 12.9, 9.8, 8.2, 4.6
Hz), 0.87 (9H, s), 0.04 (6H, s).
13C NMR (90 MHz, CDCl3): d = 167.1 (0), 153.5 (0), 145.1 (0),
142.9 (0), 135.5 (0), 126.2 (1), 124.3 (1), 121.7 (1), 121.1 (1), 119.0
(1), 112.1 (2), 70.1 (1), 46.3 (2), 36.2 (2), 32.6 (2), 32.5 (2), 26.0
(3C, 3), 18.3 (0), –4.5 (3), –4.5 (3).
LRMS (CI mode, isobutane): m/z = 450 (100%), 136 (16).
(S,Z)-4-[(Benzothiazol-2-yl)sulfinyl]methyl-1-[(1,1-dimethyl-
ethyl)dimethylsilyl]oxy-3-vinylcyclohex-3-ene (21)
IR (film): n = 2928 (s), 2856 (s), 1472 (m), 1252 (s), 1007 (s), 1004
(m), 881 (m), 836 (s), 774 (m), 760 (m) cm–1.
1H NMR (360 MHz, CDCl3, isomeric mixture - * denotes a resolved
signal arising from a single isomer): d = 8.06 (1H, dm, J = 8.2 Hz),
7.99 (1H, dm, J = 8.1 Hz), 7.56 (1H, ddd, J = 8.4, 7.3, 1.3 Hz),
7.51–7.45 (1H, m), 6.65 (1H, dd, J = 17.1, 11.0 Hz), 5.15 (1H, d,
J = 17.1 Hz), 4.96 (1H, d, J = 11.0 Hz), 4.17 (1H*, d, J = 13.1 Hz),
4.09 (1H*, d, J = 13.0 Hz), 4.03 (1H*, d, J = 13.1 Hz), 3.96 (1H*, d,
J = 12.8 Hz), 3.99–3.90 (1H, m), 2.52–2.20 (3H, m), 2.19–2.08
(1H, m), 1.85–1.74 (1H, m), 1.68–1.56 (1H, m), 0.89 (9H*, s), 0.88
(9H*, s), 0.07 (3H, s), 0.07 (3H, s).
LRMS (EI+mode): m/z = 417 (37%), 370 (25), 285 (17), 252 (17),
224 (26), 193 (17), 149 (18), 119 (100), 91 (52), 73 (64).
HRMS (EI+mode): Found M+•, 417.1619. C22H31NOS2Si requires
417.1616.
13C NMR (90 MHz, CDCl3, isomeric mixture - † denotes signals
common to both isomers): d = 177.6† (0), 153.9† (0), 136.1 (0),
136.0 (0), 135.4 (0), 135.4 (0), 133.4 (1), 133.3 (1), 127.0† (1),
126.3† (1), 124.5 (0), 124.3 (0), 124.1 (1), 124.0 (1), 122.4 (1),
122.4 (1), 114.4 (2), 114.3 (2), 67.4 (1), 67.2 (1), 61.9 (2), 61.8 (2),
35.1† (2), 31.6 (2), 31.4 (2), 31.0 (2), 30.6 (2), 26.0† (3C, 3), 18.3†
(0), –4.5† (3), –4.5† (3).
Oxidation of Thioether 19
A stirred solution of the thioether 19 (200 mg, 0.48 mmol) in EtOH
(5 mL) at 0 °C was treated with ammonium heptamolybdate tet-
rahydrate (150 mg, 0.12 mmol) in 30% H2O2 (230 mg, 2.0 mmol).
The resulting yellow suspension was allowed to stir for 2 h at 0 °C
and then for a further 4 h at r.t. The mixture was then diluted with
H2O (10 mL) and extracted (4 ¥ 10 mL Et2O). The combined organ-
ic extracts were then dried (MgSO4) and concentrated in vacuo. The
residue was then further purified via column chromatography (elut-
ing with 10–25% Et2O in hexanes) to yield in order of elution: the
sulfone 17 (44 mg, 0.10 mmol, 21%), the isomeric sulfone 20 (28
mg, 0.06 mmol, 13%) and its parent sulfoxides 21 (113 mg, 0.26
mmol, 54%, dr = 1:1) all as clear oils.
LRMS (CI mode, isobutane): m/z = 434 (100%), 251 (20), 184 (20),
119 (39).
Acknowledgement
We thank the EPSRC; the Committee of Scientific Research, Repu-
blic of Poland (grant No. 3T09A 007 10, travel grant No. WAR/
992/067); the British Council and Rhône-Poulenc Rorer for a CASE
studentship (PRB).
(Z,S)-2-[2-[5-(tert-Butyldimethylsilyloxy)-2-methylenecyclo-
hexylidene]ethylsulfanyl]benzothiazole (17)
[a]D = +9.2 (c = 0.48, CHCl3).
IR (film): n = 2930 (s), 2856 (s), 1472 (m), 1332 (s), 1252 (m), 1149
(s), 1091 (s), 868 (m), 837 (m), 763 (m) cm–1.
1H NMR (360 MHz, CDCl3): d = 8.23 (1H, dm, J = 7.6 Hz), 8.02
(1H, dm, J = 7.6 Hz), 7.65 (1H, ddd, J = 7.2, 7.2, 1.4 Hz), 7.60 (1H,
ddd, J = 7.3, 7.3, 1.3 Hz), 5.35 (1H, t, J = 7.6 Hz), 4.99 (1H, br s),
4.83 (1H, m), 4.57 (1H, dd, J = 14.2, 8.9 Hz), 4.28 (1H, ddd,
J = 13.0, 6.2, 1.2 Hz), 3.55 (1H, tt, J = 8.8, 3.8 Hz), 2.42 (1H, dd,
J = 12.9, 3.9 Hz), 2.25 (1H, dt, J = 12.1, 4.4 Hz), 2.23–2.16 (1H,
m), 1.77–1.67 (2H, m), 1.55–1.46 (1H, m), 0.84 (9H, s), 0.00 (3H,
s), –0.01 (3H, s).
13C NMR (90 MHz, CDCl3): d = 166.0 (0), 152.9 (0), 149.0 (0),
144.5 (0), 137.0 (0), 128.2 (1), 127.8 (1), 125.6 (1), 122.5 (1), 112.8
(2), 108.9 (1), 70.3 (1), 55.4 (2), 46.8 (2), 36.1 (2), 32.3 (2), 26.0
(3C, 3), 18.3 (0), –4.6 (3), –4.6 (3).
References
(1) Okamura, W. H.; Zhu, G. Chem. Rev. 1995, 95, 1877.
(2) Kocienski, P. J.; Lythgoe, B.; Ruston, S. J. Chem. Soc., Perkin
Trans. I 1979, 1290.
(3) Kocienski, P. J. Comprehensive Organic Synthesis; Trost, B.
M., Fleming, I., Eds.; Pergamon: Oxford, 1991; Vol. 6, p 975–
1010.
(4) Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel, O. Tetrahedron
Lett. 1991, 32, 1175.
(5) Baudin, J. B.; Hareau, G.; Julia, S. A.; Ruel, O. Bull. Soc.
Chim. Fr. 1993, 130, 336.
(6) Baudin, J. B.; Hareau, G.; Julia, S. A.; Lorne, R.; Ruel, O.
Bull. Soc. Chim. Fr. 1993, 130, 856.
(7) Toh, H. T.; Okamura, W. H. J. Org. Chem. 1983, 48, 1414.
(8) Wang, Y.; Ting, H.-S.; Huang, J.-J.; Chow, Y.-C.; Huang, Y.-
T. Acta Chim. Sin. 1958, 24, 126.
LRMS (CI mode, isobutane): m/z = 450 (100%), 136 (26).
HRMS (CI mode): Found (M+H)+, 450.1595. C22H32NO3S2Si re-
quires 450.1593.
Synthesis 1999, No. 7, 1209–1215 ISSN 0039-7881 © Thieme Stuttgart · New York