Remote Asymmetric Bromination Reaction with Vinylketene Silyl N,O-Acetal and Its Application to Total Synthesis of Pellasoren A.

Stereoselective bromination of the E,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary has been achieved and applied to introduction of heteroatom at γ-position of α,β-unsaturated imide. The reactions proceeded in high stereoselectivity. Total synthesis of pellasoren A, an antitumor propionate from the myxobacteriun Sorangium cellulosum, has been accomplished in short steps by this methodology and our method of reduced polypropionate synthesis.