Short synthesis of (±)-hirsutine: Direct addition of dimethyl malonate anion to a 1,4-conjugate iminium salt of appropriate 3-ethylindolo[2,3-a]quinolizidine
作者:Mauri Lounasmaa、Jari Miettinen、Pirjo Hanhinen、Reija Jokela
DOI:10.1016/s0040-4039(97)00056-7
日期:1997.2
Direct addition of dimethyl malonate anion to a 1,4-conjugate iminium salt of 3-ethylindolo[2,3-a]quinolizidine 4a (regenerated from the corresponding alpha-aminonitrile 4b) afforded enamine 5. Catalytic hydrogenation of compound 5, led stereoselectively to compound 6 (pseudo), which is the highly desired intermediate for the preparation of several Corynanthe alkaloids, including (+/-)-hirsutine 7. (C) 1997 Elsevier Science Ltd.