A rapid and efficient access to renieramycin-type alkaloids featuring a temperature-dependent stereoselective cyclization

Abstract

A flexible and practical protocol for the asymmetric synthesis of renieramycin-type antitumor alkaloids is described, in which the stereoselective Pictet–Spengler cyclization of amino ester 16 and aldehyde 15 by regulating temperature and the automatic lactamization after N-deprotection of the cyclization product are exploited to rapidly construct the common pentacyclic framework. (–)-Renieramycin G and (–)-jorunnamycin A, as representative members of the two subgroup renieramycin-type alkaloids, are obtained in 19 steps from L-tyrosine with 15.8% and 14.3% overall yield respectively.