Total Syntheses of the Lycopodium Alkaloids (±)-Fawcettimine and (±)-8-Deoxyserratinine

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.