Vinylogous Mannich reactions. Stereoselective formal synthesis of pumiliotoxin 251D
作者:Stephen F. Martin、Scott K. Bur
DOI:10.1016/s0040-4020(99)00452-4
日期:1999.7
A concise synthesis of (−)-3, a known precursor of pumiliotoxin 251D, has been completed using a vinylogous Mannich reaction as a key construction. Silyloxyfuran 10 added to methoxypyrrolidine 20 in the presence of TMS-OTf to give a mixture (4.8:1) of 21 and 22 in 57% yield. Reduction and global deprotection of 21 afforded the bicyclic lactam 23. Raney Nickel mediated extrusion of the hydroxymethyl
使用乙烯基曼尼希反应作为关键结构,完成了已知的pumiliotoxin 251D前体(-)- 3的简明合成。在TMS-OTf存在下,将甲硅烷氧基呋喃10加至甲氧基吡咯烷20中,以57%的收率得到21和22的混合物(4.8:1)。还原和整体脱保护的21提供了双环内酰胺23。Raney Nickel介导的23羟甲基的挤出得到(-)- 3。