Total syntheses of the lycopodium alkaloids (.+-.)-fawcettimine and (.+-.)-8-deoxyserratinine.
作者:TAKASHI HARAYAMA、MUNEO TAKATANI、YASUO INUBUSHI
DOI:10.1248/cpb.28.2394
日期:——
Total syntheses of (±)-fawcettimine (1) and (±)-8-deoxyserratinine (3) have been accomplished. Selective hydrogenation of the conjugated nitrile (6) over (Ph3P)3RhCl, followed by reduction with LiAlH4 and treatment of the product with N3CO2-tert-Bu yielded the carbamate (8). Successive treatment of 8 with Na-liquid NH3, the Jones reagent, N-hydroxysuccinimide-DCC, CF3CO2H, and n-Bu3N in CH3CN afforded the nine-membered lactam (18). Reduction of 18 with LiBH4 gave the epimeric alcohols, 22 and 23. Both 22 and 23 were converted into the same ketone (28) via the same sequence of reactions ; reduction with LiAlH4, acylation with (CF3CO)2O-pyridine, selective hydrolysis with 0.2N KOH-MeOH, and Jones oxidation. Epoxidation of 28 gave the epimeric epoxides, 29 and 30. The epoxide (29) was successively treated with BF3·Et2O, the Jones reagent, H2-5% Pd/C, and 1N KOH-MeOH to provide (±)-fawcettimine (1). The other epoxide (30) was converted into (±)-8-deoxyserratinine (3) by successive treatments with 1N KOH-MeOH, the Jones reagent, and NaBH4.
我们完成了 (±)-fawcettimine (1) 和 (±)-8-deoxyserratinine (3) 的全合成。用 (Ph3P)3RhCl 对共轭腈 (6) 进行选择性氢化,然后用 LiAlH4 还原,并用 N3CO2-tert-Bu 处理产物,得到氨基甲酸酯 (8)。用 Na-liquid NH3、琼斯试剂、N-羟基琥珀酰亚胺-DCC、CF3CO2H 和正-Bu3N 在 CH3CN 中连续处理 8,可得到九元内酰胺(18)。用 LiBH4 还原 18 得到了 22 和 23 这两种二元醇。通过相同的反应顺序:用 LiAlH4 还原、用 (CF3CO)2O 吡啶酰化、用 0.2N KOH-MeOH 选择性水解和琼斯氧化,22 和 23 被转化成相同的酮 (28)。28 的环氧化反应生成了环氧化物 29 和 30。环氧化物(29)先后用 BF3-Et2O、琼斯试剂、H2-5% Pd/C 和 1N KOH-MeOH 处理,得到 (±)-fawcettimine (1)。用 1N KOH-MeOH、琼斯试剂和 NaBH4 连续处理另一个环氧化物 (30) 后,可将其转化为 (±)-8-deoxyserratinine (3)。