Total synthesis of the bacterial RNA polymerase inhibitor ripostatin B.

A modular and highly stereoselective synthesis of the title compound was developed. Key steps in the assembly of the carbon framework of ripostatin B were a stereoselective Paterson aldol reaction and a high-yielding ring-closing metathesis mediated by Grubbs first generation catalyst. The C15 hydroxy group was established through Tishchenko-Evans reduction in excellent yield and selectivity.