Total Syntheses of (+)-Haplophytme

摘要

Haplophytine (1) is a heterodimeric alkaloid found in the leaves of the Mexican plant Haplophyton cimicidum. Hap-lophytine possesses an intriguing complex skeleton which can be subdivided into two domains: a left-hand domain made of a tetracyclic heterocycle, which includes a bridged ketone, and a right-hand indolic domain known as aspidophitine, which incorporates a fused lactone. The two domains are connected at a quaternary carbon center. Upon exposure to HBr, haplophytine undergoes a unique 1,2-rearrangement leading to the imminium compound 2 (Scheme 1).