Catalytic enantioselective construction of quaternary stereocenters by direct vinylogous Michael addition of deconjugated butenolides to nitroolefins

A direct vinylogous Michael reaction of gamma-substituted deconjugated butenolides with nitroolefins has been developed with the help of a newly identified quinine-derived bifunctional catalyst, allowing the synthesis of densely functionalized products with contiguous quaternary and tertiary stereocenters in excellent yield with perfect diastereoselectivity (>20 : 1 dr) and high enantioselectivity (up to 99 : 1 er).

Catalytic Asymmetric Synthesis of alpha,beta-Disubstituted alpha,gamma-Diaminophosphonic Acid Precursors by Michael Addition of alpha-Substituted Nitrophosphonates to Nitroolefins

Michael additions of alpha-substituted nitrophosphonates to various nitroolefins are shown to proceed with high diastereo- and enantioselectivity when catalyzed by a quinine-derived thiourea-tertiary amine bifunctional catalyst and generate alpha,gamma-diaminophosphonic acid precursors with contiguous quaternary and tertiary stereocenters.

Catalytic Aldol-Cyclization Cascade of 3-Isothiocyanato Oxindoles with alpha-Ketophosphonates for the Enantioselective Synthesis of beta-Amino-alpha-hydroxyphosphonates

A cascade aldol cyclization reaction between 3-isothiocyanato oxindoles and alpha-ketophosphonates has been developed for the synthesis of beta-amino-alpha-hydroxyphosphonate derivatives. Catalyzed by a quinine-based tertiary amino-thiourea derivative, this reaction delivers 2-thioxooxazolidinyl phosphonates based on a spirooxindole scaffold bearing two contiguous quaternary stereogenic centers in high yields with excellent diastereo- (up to >20:1 dr) and enantioselectivities (up to >99:1 er).