S. Ramadas, G. L. D. Krupadanam / Tetrahedron: Asymmetry 15 (2004) 3381–3391
3387
5.17. ( )-cis-41-Chloro-4-acetoxyflavan 11d
78.0 (C-4), 79.7 (C-2), 120.9 (C-6), 118.6 (C-8), 125.2
(C-4a), 128.2 (C-5), 126.6 (C-21, 61), 127.5 (C-31, 51),
135.6 (C-41), 130.3 (C-7), 140.3 (C-11), 152.3 (C-8a),
and 170.5 (OCOCH3). MS (m/z) 302 (M+), 304 (M2+).
HRMS calcd for C17H15ClO3 (M+), 302.0763. Found:
302.0742.
1H NMR: d 2.10 (s, OCOCH3), 2.12 (m, He-3), 2.62 (m,
Ha-3), 5.20 (dd, J = 14.0, 2.0Hz, H-4), 6.18 (dd,
J = 14.0, 8.0Hz, H-2), 6.92 (m, H-6,8), 7.20 (m, H-5,7)
and 7.40 (m, H-21, 31, 51, 61). 13C NMR: 20.6
(OCOCH3), 37.1 (C-3), 75.4 (C-4), 75.2 (C-2), 115.4
(C-8), 120.7 (C-6), 121.3 (C-4a), 126.5 (C-21, 61), 127.8
(C-31, 51), 128.7 (C-5), 130.0 (C-7), 138.3 (C-41), 138.1
(C-11), 154.9 (C-8a), and 170.2 (OCOCH3). MS (m/z)
302 (M+), 304 (M2+). HRMS calcd for C17H15ClO3
(M+), 302.0763. Found: 302.0789.
5.22. ( )-cis-6-Chloro-41-methoxy-4-acetoxyflavan 11i
1H NMR: d 2.14 (s, OCOCH3), 2.10 (m, He-3), 2.60 (m,
Ha-3), 3.80 (s, OCH3), 5.11 (dd, J = 14.0, 2.0Hz, H-4),
6.10 (dd, J = 14.0, 8.0Hz, H-2), 6.80 (d, J = 10.0Hz,
H-8), 6.86 (d, J = 10.0Hz, H-31, 51), 7.15 (dd, J = 10.0,
2.0Hz, H-7), 7.25 (d, J = 2.0Hz, H-5), and 7.30 (d,
J = 10.0Hz, H-21, 61). 13C NMR: 21.1 (OCOCH3),
35.2 (C-3), 55.3 (OCH3), 77.6 (C-2), 78.2 (C-4), 119.1
(C-8), 128.2, (C-31, 51), 128.5 (C-5), 125.7 (C-4a),
127.4 (C-21, 61), 121.4 (C-6), 138.9 (C-7), 131.9 (C-11),
153.9 (C-8a), 138.7 (C-41), and 170.7 (OCOCH3). MS
(m/z) 332 (M+), 334 (M2+). HRMS calcd for
C18H17ClO4 (M+), 332.0826. Found: 332.0851.
5.18. ( )-cis-21-Chloro-4-acetoxyflavan 11e
1H NMR: d 2.12 (s, OCOCH3), 2.08 (m, He-3), 2.81 (m,
Ha-3), 5.18 (dd, J = 14.0, 2.0Hz, H-4), 5.95 (dd,
J = 14.0, 8.0Hz, H-2), 6.91 (dd, J = 10.0, 2.0, H-8),
7.05 (m, H-6), 7.19–7.52 (m, H-7, 31, 41, 51), 7.58 (dd,
J = 10.0, 2.0Hz, H-5), and 7.74 (dd, J = 10.0, 2.0Hz,
H-61). 13C NMR: d 20.9 (OCOCH3), 38.4 (C-3), 65.6
(C-4), 74.1 (C-2), 116.8 (C-8), 122.4 (C-6), 126.3 (C-
4a), 127.5 (C-51), 128.0 (C- 5), 138.4 (C-41), 129.7 (C-
7), 129.2 (C-61), 129.8 (C-31), 125.5 (C-21), 139.6 (11),
155.6 (C-8a), and 170.7 (OCOCH3). MS (m/z) 302
(M+), 304 (M2+). HRMS calcd for C17H15ClO3 (M+),
302.0763. Found: 302.0738.
5.23. ( )-cis-6-Bromo-4-acetoxyflavan 11j
1H NMR: d 2.11 (s, OCOCH3), 2.15 (m, He-3), 2.50 (m,
Ha-3), 4.91 (dd, J = 14.0, 2.0Hz, H-4), 5.15 (dd,
J = 14.0, 8.0Hz, H-2), 6.72 (d, J = 10.0Hz, H-8), 7.16
(dd, J = 10.0, 2.0 H-7), 7.35 (m, H-21–61), and 7.45 (d,
J = 2.0Hz, H-5). 13C NMR: 21.8 (OCOCH3), 37.4 (C-
3), 63.6 (C-4), 76.5 (C-2), 117.6 (C-8), 123.5 (C-6),
126.0, (C-4a), 127.7 (C-5), 128.3 (C-21, 61), 128.7
(C-31, 51), 136.2 (C-41), 131.5 (C-7), 142.0 (C-11),
151.3 (C-8a) and 171.8 (OCOCH3). MS (m/z) 346
(M+), 348 (M2+). HRMS calcd for C17H15BrO3 (M+),
346.0218. Found: 346.0245.
5.19. ( )-cis-31,41-Methylenedioxy-4-acetoxyflavan 11f
1H NMR: d 2.18 (s, OCOCH3), 2.12 (m, He-3), 2.47 (m,
Ha-3), 5.15 (dd, J = 14.0, 2.0Hz, H-4), 5.92 (dd,
J = 14.0, 8.0Hz, H-2), 6.10 (s, OCH2O), 6.87 (dd,
J = 10.0, 2.0Hz, H-8), 6.95–7.15 (m, H-6, 21, 51, 61),
7.25 (m, H-7), and 7.51 (dd, J = 10.0, 2.0Hz, H-5). 13C
NMR: d 20.1 (OCOCH3), 38.1 (C-3), 65.8 (C-4), 76.4
(C-2), 101.5 (OCH2O), 129.2, (C-21), 130.2 (C-51),
117.7 (C-8), 121.5 (C-6), 123.6 (C-61), 126.7 (C-4a),
128.2 (C-5), 132.6 (C-7), 137.8 (C-11), 136.9 (C-41),
148.2 (C-31), 155.4 (C-8a), and 171.4 (OCOCH3). MS
(m/z) 312 (M+). HRMS calcd for C18H16O5 (M+),
312.1025. Found: 312.1048.
5.24. ( )-cis-6-Bromo-7-methoxy-4-acetoxyflavan 11k
1H NMR: d 2.18 (s, OCOCH3), 2.16 (m, He-3), 2.48 (m,
Ha-3), 3.87 (s, OCH3), 4.90 (dd, J = 14.0, 2.0Hz, H-4),
5.16 (dd, J = 14.0, 8.0Hz, H-2), 6.64 (s, H-8), 7.12 (s,
H-5), and 7.54 (m, H-21–61). 13C NMR: 22.2
(OCOCH3), 36.2 (C-3), 56.3 (OCH3), 65.5 (C-4), 74.8
(C-2), 122.2 (C-6), 116.8 (C-8), 126.4, (C-5), 126.1
(C-4a), 127.9 (C-21, 61), 130.3 (C-31, 51), 137.5 (C-41),
137.6 (C-11), 150.3 (C-8a), 132.5 (C-7), and 171.4
(OCOCH3). MS (m/z) 376 (M+), 378 (M2+).
HRMS calcd for C18H17BrO4 (M+), 376.0335. Found:
376.0363.
5.20. ( )-cis-6-Chloro-4-acetoxyflavan 11g
1H NMR: d 2.10 (s, OCOCH3), 2.12 (m, He-3), 2.62 (m,
Ha-3), 5.18 (dd, J = 14.0, 2.0Hz, H-4), 6.10 (dd,
J = 14.0, 8.0Hz, H-2), 6.83 (d, J = 10.0Hz, H-8), 7.15
(m, H-7), and 7.35 (m, H-5, 21–61). 13C NMR: 20.9
(OCOCH3), 35.3 (C-3), 77.6 (C-2), 79.5 (C-4), 118.0
(C-8), 121.8 (C-6), 129.0 (C-5), 125.6 (C-4a), 128.5 (C-
31, 51), 128.0 (C-21, 61), 128.5 (C-7), 139.5 (C- 41),
139.7 (C-11), 150.8 (C-8a), and 170.7(OCOCH3). MS
(m/z) 302 (M+), 304 (M2+). HRMS calcd for
C17H15ClO3 (M+), 302.0763. Found: 302.07776.
5.25. ( )-cis-7,8-Dimethoxy-41-hydroxy-4-acetoxyflavan
11l
1H NMR: d 2.04 (s, OCOCH3), 2.75 (m, He-3), 3.16 (m,
Ha-3), 3.80 (s, OCH3-8), 3.92 (s, OCH3-7), 4.84 (dd,
J = 14.0, 2.0Hz, H-4), 5.41 (dd, J = 14.0, 8.0Hz, H-2),
6.62 (d, J = 10.0Hz, H-6), 6.78 (d, J = 10.0Hz, H-31,
51), 7.31 (d, J = 10.0Hz, H-21, 61), and 7.56 (d,
J = 10.0Hz, H-5). 13C NMR: 19.5 (OCOCH3), 38.6
(C-3), 55.7 (OCH3-7), 59.2 (OCH3-8) 65.5 (C-4), 78.4
(C-2), 124.8 (C-6), 127.3 (C-4a), 128.4 (C-31, 51), 126.8
(C-21, 61), 128.6 (C-5), 139.5 (C-11), 118.3 (C-8), 130.2
(C-7), 138.6 (C-41), 155.6 (C-8a), and 171.8 (OCOCH3).
5.21. ( )-cis-8-Chloro-4-acetoxyflavan 11h
1H NMR: d 2.10 (s, OCOCH3), 2.17 (m, He-3), 2.70 (m,
Ha-3), 5.35 (dd, J = 14.0, 2.0Hz, H-4), 6.17 (dd,
J = 14.0, 8.0Hz, H-2), 6.90 (dd, J = 10.0, 10.0Hz, H-
6), 7.13 (dd, J = 10.0, 2.0Hz, H-7), and 7.25–7.55 (m,
H-5, 21–61). 13C NMR: d 20.6 (OCOCH3), 39.6 (C-3),