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A. Anikin et al. / Tetrahedron 59 (2003) 5295–5305
HMQC, HMBC) d 0.79 (s, 3H, CH3-19), 0.86 (s, 3H, CH3-
18), 0.89 (m, 1H, 1-Ha), 1.01 (s, 3H, CH3-20), 1.18 (m, 1H,
3-Ha), 1.30 (s, 3H, CH3-17), 1.33 (s, 3H, CH3-16), 1.34–
1.40 (m, 2H, 2-Ha, 3-Hb), 1.43–1.53 (m, 2H, 5-H, 6-Hb),
1.56–1.68 (m, 1H, 2-Hb), 1.82–1.91 (m, 1H, 6-Ha), 2.42
(ddd, 1H, J1b,2a¼1.7 Hz, J1b,2b¼4.8 Hz, J1b,1a¼13.1 Hz,
1-Hb), 2.55 and 2.71 (AB system, 1H, J¼17.6 Hz, CH2-12),
2.86 (s, 1H, 9-H), 3.67 (dd, 1H, J7,6a¼2.4 Hz, J7,6b¼3.5 Hz,
7-H), 5.04 (d, 1H, J15b,14¼17.5 Hz, 15-Hb), 5.05 (d, 1H,
J15a,14¼10.8 Hz, 15-Ha) 5.88 (ddd, 1H, Jlong range¼0.7 Hz,
J14,15a¼10.8 Hz, J14,15b¼17.5 Hz, 14-H); 13C NMR
(75.4 MHz, APT, HMQC, HMBC) d 15.27 (C-20, 2),
18.47 (C-2, þ), 21.73 (C-19, 2), 24.71 (C-6, þ), 27.06
(C-17, 2), 30.76 (C-16, 2), 32.79 (C-4, þ), 33.34 (C-18,
2), 37.07 (C-10, þ), 39.07 (C-1, þ), 41.96 (C-3, þ), 46.00
(C-5, 2), 49.72 (C-12, þ), 61.71 (C-9, 2), 72.67 (C-7, 2),
75.67 (C-13, þ), 79.65 (C-8, þ), 112.32 (C-15, þ), 145.82
(C-14, 2), 207.99 (C-11, þ); C20H32O3 (320.47, 320.2351),
FAB MS: m/z¼342.8 [MþNa]þ. Crystal data for C20H32O3:
diketone 14b (106.0 mg, 0.333 mmol) in ethanol (10 mL).
The mixture was stirred for 15 min and after addition of
water (0.2 mL) for another 30 min. Solvent evaporation and
FC (petroleum ether–CHCl3–EtOAc 5:5:2) furnished 14a
(12.1 mg, 11%) and 14c (93.6 mg, 88%). Mp 86–888C
(from petroleum ether); [a]2D0¼2106 (c 2.0, CHCl3); IR
(KBr): 3469, 1714, 1388, 1178, 1072 cm21 1H NMR
;
(600 MHz, H,H COSY, HMQC, HMBC) d 0.75–0.79 (m,
1H, 1-Ha), 0.81 (s, 3H, CH3-19), 0.87 (s, 3H, CH3-18), 0.91
(dd, 1H, J5,6a¼2.1 Hz, J5,6b¼12.5 Hz, 5-H), 1.01 (s, 3H,
CH3-20), 1.06–1.16 (m, 1H, 3-Ha), 1.28/1.29 (2s, 6H, CH3-
16, CH3-17), 1.29 (m mostly hidden by the 1.28/1.29
singlets, 1H, 6-Hb), 1.36–1.40 (m, 2H, 2-Ha, 3-Hb), 1.59–
1.67 (m, 1H, 2-Hb), 1.84 (ddd, 1H, J6a,5¼2.1 Hz,
J6a,7¼4.2 Hz, J6a,6b¼13.1 Hz, 6-Ha), 2.22 (br s, 1H, OH),
2.41–2.45 (m, 1H, 1-Hb), 2.51 (s, 1H, 9-H), 2.56 and 2.62
(AB system, 2H, J¼17.8 Hz, CH2-12), 3.83 (dd, 1H,
J7,6a¼4.2 Hz, J7,6b¼11.5 Hz, 7-H), 5.04 (dd, 1H,
J15a,15b¼1.1 Hz, J15a,14¼10.5 Hz, 15-Ha) and 5.19 (dd,
1H, J15b,15a¼1.1 Hz, J15b,14¼17.3 Hz, 15-Hb), 5.93 (dd,
1H, J14,15a¼10.5 Hz, J14,15b¼17.3 Hz, 14-H); 13C NMR
(150.9 MHz, APT, HMQC, HMBC) d 15.75 (C-20, 2),
18.41 (C-2, þ), 21.79 (C-19, 2), 22.24 (C-17, 2), 26.80
(C-6, þ), 31.31 (C-16, 2), 33.33 (C-4, þ), 33.67 (C-18, 2),
37.68 (C-10, þ), 39.28 (C-1, þ), 41.82 (C-3, þ), 50.22
(C-12, þ), 53.28 (C-5, 2), 65.44 (C-9, 2), 75.43 (C-13, þ),
80.52 (C-8, þ), 80.79 (C-7, 2), 112.35 (C-15, þ), 146.58
(C-14, 2), 206.71 (C-11, þ); C20H32O3 (320.47, 320.2351),
FAB MS: m/z 343.1 [MþNa]þ.
˚
˚
space group P21, a¼7.2382(11) A, b¼11.6093(17) A,
˚
c¼11.0671(16) A, b¼96.558(3)8. Full crystallographic
details have been deposited with the Cambridge Crystal-
lographic Data Centre (CCDC 196904). Copies may be
obtained free of charge on application to the Director,
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (e-mail:
deposit@c.ck.cam.ac.uk).
4.1.10. (8S,13R)-8,13-Epoxy-14-labdene-7,11-dione
(14b). A solution of olefin 14a (0.75 mg, 2.34 mmol) in
DMSO (30 mL) was added at 208C to a stirred solution of
IBX (1.31 mg, 4.68 mmol) in DMSO (20 mL). After 2 h
water (50 mL) was added and the white precipitated was
removed by filtration and washed carefully with water
(2£10 mL), and CH2Cl2 (5£40 mL). Extraction of the water
phase with CH2Cl2 (3£20 mL), combining of the CH2Cl2
solutions, solvent removal and FC (petroleum ether–
CHCl3–EtOAc 5:5:1) gave diketone 14b (0.73 g, 99%).
Mp 173–1748C (from petroleum ether); [a]2D0¼2129 (c 2.0,
4.1.12. (7S,8S,13R)-7-Acetoxy-8,13-epoxy-14-labden-11-
one (14d). Acetic anhydride (54.0 mL) was added to a
solution of 7b-hydroxy compound 14c (61.0 mg,
0.190 mmol), anhydrous pyridine (0.5 mL) and a catalytic
amount of DMAP in CH2Cl2 (6 mL) and the reaction
mixture was stirred for 2 h. Stirring was maintained for
30 min after addition of water (2 mL). Standard work-up
(10% aqueous HCl, water, dichloromethane) and purifi-
cation by FC (petroleum ether–CHCl3–EtOAc 5:5:1) gave
7b-acetoxy derivative 14d (67.8 mg, 98%). Mp 127–1288C
(from petroleum ether); [a]2D0¼2122 (c 2.0, CHCl3); IR
(KBr): 1732, 1392, 1243, 1034 cm21; 1H NMR (600 MHz,
HMQC, HMBC) d 0.75–0.78 (m, 1H, 1-Ha), 0.79 (s, 3H,
CH3-19), 0.86 (s, 3H, CH3-18), 0.97 (dd, 1H, J5,6a¼2.1 Hz,
J5,6b¼13.1 Hz, 5-H), 1.04 (s, 3H, CH3-20), 1.11–1.16 (m,
1H, 3-Ha), 1.21 (s, 3H, CH3-16), 1.30 (s, 3H, CH3-17),
1.32–1.40 (m, 3H, 2-Ha, 3-Hb, 6-Hb), 1.57–1.66 (m, 1H,
2-Hb), 1.82 (ddd, 1H, J6a,5¼2.1 Hz, J6a,7¼4.7 Hz,
J6a,6b¼13.1 Hz, 6-Ha), 2.09 (s, 3H, CH3CO), 2.39–2.43
(m, 1H, 1-Hb), 2.50 and 2.61 (AB system, 2H, J¼18.3 Hz,
CH2-12), 2.67 (s, 1H, 9-H), 5.05 (dd, 1H, J15a,15b¼1.0 Hz,
J15a,14¼10.6 Hz, 15-Ha), 5.08 (dd, 1H, J7,6a¼4.7 Hz,
J7,6b¼12.0 Hz, 7-H), 5.27 (d, 1H J15a,15b¼1.0 Hz,
J15b,14¼17.2 Hz, 15-Hb), 5.93 (dd, 1H, J14,15a¼10.6 Hz,
J14,15b¼17.2 Hz, 14-H); 13C NMR (75.4 MHz, APT,
HMQC, HMBC) d 15.70 (C-20, 2), 18.36 (C-2, þ), 21.52
(CH3CO, 2), 21.72 (C-19, 2), 23.11 (C-17, 2), 25.71 (C-6,
þ), 31.52 (C-16, 2), 33.33 (C-4, þ), 33.48 (C-18, 2), 37.23
(C-10, þ), 39.14 (C-1, þ), 41.73 (C-3, þ), 50.37 (C-12, þ),
53.02 (C-5, 2), 65.60 (C-9, 2), 75.23 (C-13, þ), 78.77
(C-8, þ), 81.08 (C-7, 2), 112.77 (C-15, þ), 146.39 (C-14, 2),
170.55 (CH3CO, þ), 206.68 (C-11, þ); C22H34O4 (362.51,
362.2457), FAB MS: m/z 363.2 [MþH]þ. Crystal data for
1
CHCl3); IR (KBr): 1722 cm21; H NMR (400 MHz, H,H
COSY, HMQC, HMBC) d 0.72–0.76 (m, 1H, 1-Ha), 0.77 (s,
3H, CH3-19), 0.79 (s, 3H, CH3-18), 1.08 (dd, 1H,
J5,6a¼3.2 Hz, J5,6b¼13.8 Hz, 5-H), 1.10–1.13 (m, 1H,
3-Ha), 1.18 (s, 3H, CH3-20), 1.30 (s, 3H, CH3-16), 1.34–
1.41 (m, 2H, 2-Ha, 3-Hb), 1.38 (s, 3H, CH3-17), 1.55–1.62
(m, 1H, 2-Hb), 2.40 (dd, 1H, J6a,5¼3.2 Hz, J6a,6b¼14.1 Hz,
6-Ha), 2.44–2.48 (m, 1H, 1-Hb), 2.47 (dd, 1H,
J6b,5¼13.8 Hz, J6b,6a¼14.1 Hz, 6-Hb), 2.53 and 2.60 (AB
system, 2H, J¼18.7 Hz, CH2-12), 2.99 (s, 1H, 9-H), 5.04
(dd, 1H, J15a,15b¼1.1 Hz, J15a,14¼10.9 Hz, 15-Ha), 5.21 (dd,
1H, J15b,15a¼1.1 Hz, J15b,14¼17.3 Hz, 15-Hb), 5.88 (dd, 1H,
J14,15a¼10.9 Hz, J14,15b¼17.3 Hz, 14-H); 13C NMR
(75.4 MHz, APT, HMQC, HMBC) d 15.08 (C-20, 2),
18.07 (C-2, þ), 21.09 (C-19, 2), 26.88 (C-17, 2), 31.70
(C-16, 2), 32.90 (C-18, 2), 33.75 (C-4, þ), 36.19 (C-6, þ),
37.19 (C-10, þ), 39.20 (C-1, þ), 41.40 (C-3, þ), 49.70
(C-12, þ), 54.89 (C-5, 2), 66.14 (C-9, 2), 75.24 (C-13, þ),
81.40 (C-8, þ), 113.96 (C-15, þ), 145.65 (C-14, 2), 205.28
(C-11, þ), 207.85 (C-7, þ); C20H30O3 (318.46, 318.2195),
FAB MS: m/z 319.2 [MþH]þ.
4.1.11. (7S,8S,13R)-8,13-Epoxy-7-hydroxy-14-labden-
11-one (14c). A solution of NaBH4 (6.3 mg, 0.167 mmol)
in ethanol (0.8 mL) was added to a cooled (08C) solution of