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

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 stereocontrolSupport has been provided by the University of the Basque Country UPV/EHU (UFI QOSYC 11/22), the Basque Government (GV grant No IT-1236-19), and the Ministerio de Economía y Competitividad (MEC Grant CTQ2016-78487-C2), Spain. I.I. and O.O. thank GV for a fellowship. G.Z. and E.G.-B thank the European Funding Horizon 2020-MSCA (ITN-EJD CATMEC 14/06-721223)