Palladium-catalyzed elimination reactions of stereodefined enol triflates.

摘要

The following dissertation will describe palladium-catalyzed reactions of stereodefined enol triflates, which are readily accessible from the corresponding beta-ketoesters. Both 2,4- dienoate esters and chiral allenic esters are highly referenced synthetic intermediates. Through manipulation of reaction conditions, a general procedure for obtaining 2,4-dienoate esters from either [Z]- or [E]- enol triflates is presented. Using a chiral palladium catalyst, a highly enantioselective synthesis of allenic esters is demonstrated, which is proposed to proceed through a mechanism involving enantioselective beta-hydride elimination. The development of novel chiral ligands for this purpose is put forth. This methodology is applied to a formal total synthesis of the natural product (+) epibatidine.