7122
T. G. van Aardt et al. / Tetrahedron 57 12001) 7113±7126
2H), 3.69±3.77 62-H, m, 1H), 3.75, 3.84, 3.88 63£OCH3,
3£s, 3£3H), 4.27 63-H, d, J11.5 Hz, 1H), 6.51 6500-H, d,
J9.0 Hz, 1H), 6.54 650-H, dd, J2.5, 8.5 Hz, 1H), 6.55
630-H, d, J2.5 Hz, 1H), 6.68 660-H, d, J8.5 Hz, 1H),
7.10±7.14 6ArH, m, 2H), 7.19 6600-H, d, J9.0 Hz, 1H),
7.24±7.33 6ArH, m, 3H), 7.45±7.51 6ArOH, m, 1H);
EI-MS found [M1H]1, 571.2550;C 31H43O6SiS [M1H]1
requires 571.2550.
trans: Rf 0.63 6Benzene) as a yellow oil; 1H NMR 6CDCl3) d
0.30, 0.32 6SiCH3, 2£s, 2£3H), 1.07 6tBu, s, 9H), 3.70, 3.83
6ArCH2S, 2£d, J12.9 Hz, 2£1H), 3.78, 3.81, 3.82
63£OCH3, 3£s, 3£3H), 3.87 63-H, ddd, J3.0, 3.9,
4.5 Hz, 1H), 3.96 64-H, dd, J1.1, 3.9 Hz, 1H), 4.24
62-Heq, ddd, J1.1, 4.5, 11.0 Hz, 1H), 4.55 62-Hax, dd,
J3.0, 11.0 Hz, 1H), 6.37 68-H, d, J2.5 Hz, 1H), 6.40
650-H, d, J8.9 Hz, 1H), 6.50 660-H, d, J8.9 Hz, 1H),
6.52 66-H, dd, J2.5, 8.5 Hz, 1H), 7.22 65-H, d,
J8.5 Hz, 1H), 7.22±7.30 6ArCH2S, m, 5H);EI-MS found
[M1H]1, 553.2445;C 31H41O5SiS [M1H]1 requires
553.2444.
1
threo: Rf 0.57 6Benzene±Me2CO 9:1) as a yellow oil; H
NMR 6CDCl3) d 0.12, 0.20 62£SiCH3, 2£s, 2£3H), 1.03
6tBu, s, 9H), 1.79±1.87 6C1±OH, m, 1H), 3.45, 3.59
6ArCH2S, 2£d, J13.0 Hz, 2£1H), 3.55, 3.74, 3.80
63£OCH3, 3£s, 3£3H), 3.89±3.97 61-CH2;2-H, m, 3H),
4.20 63-H, d, J8.5 Hz, 1H), 6.25 650-H, dd, J2.5,
8.5 Hz, 1H), 6.37 630-H, d, J2.5 Hz, 1H), 6.42 6500-H, d,
J8.9 Hz, 1H), 6.66 660-H, d, J8.5 Hz, 1H), 6.67 6600-H, d,
J8.9 Hz, 1H), 7.15±7.19 6ArH, m, 2H), 7.21±7.32 6ArH,
ArOH, m, 4H);EI-MS found [M 1H]1, 571.2576;
C31H43O6SiS [M1H]1 requires 571.2550.
3.9. 4-Benzylsulfonyliso¯avans 25 and 26
4-Benzylsulfanyliso¯avans 23 and 24 60.30 mmol),
dissolved in MeOH 65 mL), were separately treated with
4 M NaIO4 61.20 mmol) and stirred for 16 h at rt, after
which a further portion of NaIO4 60.5 equiv.) was added
and the mixture stirred for 30 min. After ®ltration the
solvent was evaporated and the residue redissolved in
EtOAc 650 mL). The organic layer was washed with
water, dried 6Na2SO4) and evaporated under reduced
pressure. The products were puri®ed by PLC.
3.8. 4-Benzylsulfanyliso¯avans 2320 and 24
Benzylsulfanylpropanols 21 and 22 60.2 mmol) in dry THF
62 mL) were separately treated with a solution of TPP-
DEAD complex [TPP 62 mmol) and DEAD 61 mmol) in
dry THF 61 mL)] at 258C for 4 h. After evaporation of the
THF the mixture was redissolved in DCM and separated by
PLC affording iso¯avans 23 and 24.
3.9.1. cis- and trans-4-Benzylsulfonyl-20-t-butyldimethyl-
silyloxy-40,7-dimethoxyiso¯avan 25. 128 mg, 680%).
cis: Rf 0.40 6Benzene±Me2CO 9:1) as a yellow oil; 1H NMR
6CDCl3) d 0.21, 0.33 6SiCH3, 2£s, 2£3H), 0.92 6tBu, s, 9H),
3.25, 3.56 6ArCH2SO, 2£d, J13.0 Hz, 2£1H), 3.79, 3.84
62£OCH3, 2£s, 2£3H), 3.94 63-H, ddd, J3.5, 4.0, 12.0 Hz,
1H), 4.23 64-H, dd, J2.0, 4.0 Hz, 1H), 4.46 62-Heq, ddd,
J2.0, 3.5, 10.5 Hz, 1H), 4.91 62-Hax, dd, J10.5, 12.0 Hz,
1H), 6.46±6.51 66-,8-,30-H, m, 3H), 6.57 650-H, dd, J2.5,
8.5 Hz, 1H), 6.61 65-H, d, J8.5 Hz, 1H), 7.02 660-H, d,
J8.5 Hz, 1H), 7.07±7.12 6ArH, m, 2H), 7.28±7.32 6ArH,
m, 3H);EI-MS found [M 1H]1, 539.2289;C 30H39O5SiS
[M1H]1 requires 539.2288.
3.8.1. cis- and trans-4-Benzylsulfanyl-20-t-butyldimethyl-
silyloxy-40,7-dimethoxyiso¯avans 23. 89mg, 686%).20
cis: 13C NMR 6CDCl3) d 24.2, 23.3 6Si6CH3)2), 18.5
6SiC6CH3)3), 26.0 6SiC6CH3)3), 36.6 6C-3), 38.2
6ArCH2S), 44.2 6C-4), 55.6, 55.7 62£OCH3), 66.2 6C-2),
101.2 6C-8), 105.4 6C-30), 106.0 6C-50), 108.4 6C-6), 115.9
6C-10), 122.4 6C-4a), 127.2 6Ar±C), 128.7 62£Ar±C), 128.9
6C-60), 129.5 62£Ar±C), 132.1 6C-5), 139.0 6Ar±C), 155.0
6C-20, C-8a), 160.0 6C-40, C-7).
1
trans: Rf 0.44 6Benzene±Me2CO 9:1) as a yellow oil; H
trans: 13C NMR 6CDCl3) d 23.6 6Si6CH3)2), 18.8
6SiC6CH3)3), 26.3 6SiC6CH3)3), 36.0 6ArCH2S), 37.6
6C-3), 43.7 6C-4), 55.5, 55.7 62£OCH3), 67.3 6C-2), 101.5
6C-8), 105.6 6C-30), 106.0 6C-50), 108.6 6C-6), 114.4 6C-4a),
123.8 6C-10), 127.4 6Ar±C), 128.9 62£Ar±C, C-60), 129.4
62£Ar±C), 132.0 6C-5), 138.3 6Ar±C), 154.4 6C-20), 156.6
6C-8a), 159.5 6C-40), 160.1 6C-7).
NMR 6CDCl3) d 0.34, 0.35 6SiCH3, 2£s, 2£3H), 1.06 6tBu,
s, 9H), 3.71±3.76 63-H, m, 1H), 3.76, 3.80 62£OCH3, 2£s,
2£3H), 3.84, 4.08 6ArCH2SO, 2£d, J13.0 Hz, 2£1H),
3.95±3.97 64-H, m, 1H), 4.24 62-Heq, dm, J11.0 Hz,
1H), 4.43 62-Hax, dd, J3.8, 11.0 Hz, 1H), 6.39 650-H, dd,
J2.5, 8.5 Hz, 1H), 6.45 68-H, d, J2.5 Hz, 1H), 6.49 630-
H, d, J2.5 Hz, 1H), 6.57 66-H, dd, J2.5, 8.5 Hz, 1H),
6.88 660-H, d, J8.1 Hz, 1H), 7.09 65-H, d, J8.5 Hz,
1H), 7.21±7.26 6ArH, m, 2H), 7.30±7.35 6ArH, m, 3H);
EI-MS found [M1H]1, 539.2287;C 30H39O5SiS [M1H]1
requires 539.2288.
3.8.2. cis- and trans-4-Benzylsulfanyl-20-t-butyldimethyl-
silyloxy-30,40,7-trimethoxyiso¯avans 24. 98 mg, 688%).
cis: Rf 0.63 6Benzene) as a yellow oil; 1H NMR 6CDCl3) d
0.15, 0.35 6SiCH3, 2£s, 2£3H), 0.86 6tBu, s, 9H), 2.76, 3.05
6ArCH2S, 2£d, J13.0 Hz, 2£1H), 3.75, 3.84, 3.91
63£OCH3, 3£s, 3£3H), 3.88 63-H, ddd, J3.0, 3.8,
11.5 Hz, 1H), 4.19 64-H, dd, J2.0, 3.8 Hz, 1H), 4.33 62-
Heq, ddd, J2.0, 3.0, 10.1 Hz, 1H), 4.65 62-Hax, dd, J10.1,
11.5 Hz, 1H), 6.33 68-H, d, J2.5 Hz, 1H), 6.40 66-H, dd,
J2.5, 8.2 Hz, 1H), 6.66 650-H, d, J8.9 Hz, 1H), 6.67
660-H, d, J8.9 Hz, 1H), 6.88 65-H, d, J8.2 Hz, 1H),
7.17±7.34 6ArCH2S, m, 5H);EI-MS found [M 1H]1,
553.2441;C 31H41O5SiS [M1H]1 requires 553.2444.
3.9.2. cis- and trans-4-Benzylsulfonyl-20-t-butyldimethyl-
silyloxy-30,40,7-trimethoxyiso¯avan 26. 103 mg, 660%).
cis: Rf 0.24 6Benzene±Me2CO 9:1) as a yellow oil; 1H NMR
6CDCl3) d 0.14, 0.34 6SiCH3, 2£s, 2£3H), 0.89 6tBu, s, 9H),
3.10, 3.65 6ArCH2SO, 2£d, J13.1 Hz, 2£1H), 3.78, 3.80,
3.92 63£OCH3, 3£s, 3£3H), 4.00 63-H, ddd, J4.0, 4.0,
12.0 Hz, 1H), 4.28 64-H, dd, J2.5, 4.0 Hz, 1H), 4.46
62-Heq, ddd, J2.5, 4.0, 10.9 Hz, 1H), 4.87 62-Hax, dd,
J10.9, 12.0 Hz, 1H), 6.45 6ArH, m, 3H), 6.61 65-H, d,