摘要:
Reduction of 3 followed by acid-catalyzed cyclization provides alpha,beta-unsaturated ester 5. As 3 can be prepared in two steps from succinimide, acrolein, and trimethyl phosphonoacetate, this is a practical method for the assembly of the indolizidine nucleus. The structure of 5 was secured by conversion to elaeokanine A, 7.