Novel anionic polycyclisation cascade. Highly stereocontrolled assembly of functionalised tetracycles akin to the middle core of the manzamines
摘要:
Substituted gramines, in the presence of iotaBuOK, react with acrolein and beta-keto-phosphonates, via a novel sequence involving a multicomponent condensation followed by an anionic polycyclisation cascade, to afford in excellent overall yields, highly functionalised tetracyclic structures akin to the middle core of the manzamines. In this unique process, Lip to eight elementary transformations take place with remarkably high chemo- and stereocontrol. (C) 2002 Elsevier Science Ltd. All rights reserved.