Synthetic Studies on Poecillastrin C: Synthesis of the C14-C35 Segment of the Macrolide Ring Model

A synthesis of the C14-C35 segment of the macrolide ring model of poecillastrin C has been achieved. The C14-C23 segment was synthesized by the stereoselective Mukaiyama aldol reaction between ketene silyl N,O-acetal possessing chiral oxazolidinone auxiliary and O-acetyl lactol prepared by the stereoselective conjugate addition followed by iodolactonization. The C24-C35 segment was constructed by three stereoselective vinylogous Mukaiyama aldol reactions. Both segments were coupled by the aldol reaction followed by diisobutylaluminium hydride (DIBALH) reduction to produce the C14-C35 moiety of the macrocyclic model.