Brønsted Base Catalyzed One-Pot Synthesis od Stereodefined Six-Member Carbocycles Featuring Transient Trienolates and a Key Intramolecular 1,6-Addition

Abstract

Acatalyst-driven one-pot reaction sequence is developed for the enantio- and diastereoselective synthesis of tetrasubstituted cyclohexenes from simple unsaturated ketones or thioesters.The method involves atertiary amine/squara- mide-catalyzed a-selective addition of transiently generated trienolates to nitroolefins,subsequent base-catalyzed double bond isomerization, and an intramolecular (vinylogous) 1,6- addition reaction, arare key carbocyclization step that proceeded with essentially perfect stereocontrol