Stereoselective Total Syntheses of the Racemic Form and the Natural Enantiomer of the Marine Alkaloid Lepadiformine via a Novel <i>N</i>-Acyliminium Ion/Allylsilane Spirocyclization Strategy
作者:Pu Sun、Cuixiang Sun、Steven M. Weinreb
DOI:10.1021/jo0201070
日期:2002.6.1
subsequent protection of the primary alcohol gave amino acetal 27. The synthesis was concluded from 27 by a four-step procedure: acid-catalyzed ring closure, amino nitrile formation, introduction of the hexyl chain by a Grignard reaction to an iminium salt, and removal of the O-benzyl protecting group to give (+/-)-lepadiformine (6). The enantioselective total synthesis of 6 started from known optically