ABSTRACT
The direct asymmetric vinylogous Mannich reaction of 3,4-dihalofuran-2(5H)-one with aldimine catalyzed by quinine was first reported, and γ-butenolides have been obtained in excellent yield (up to 98%) and enantioselectivities (up to 95% ee). The synthetic applications of this protocol are demonstrated in the preparations of γ-substituted amino butyrolactones and vicinal amino alcohols.
ABSTRACT
A series of primary-tertiary diamine catalysts were successfully applied to promote the enantioselective aldol reaction of acetone with ß,γ-unsaturated α-keto esters in excellent yields (up to 99%) and enantioselectivities (up to 96% ee).
Subject(s)
Acetone/chemistry , Diamines/chemistry , Esters/chemistry , Aldehydes/chemistry , Catalysis , Molecular Structure , StereoisomerismABSTRACT
A stereoselective [3+2] cycloaddition of isocyanoesters to methyleneindolinones catalyzed by a quinine-based thiourea-tertiary amine has been successfully developed. Just by tuning the protecting groups on substrates, a variety of optically enriched 3,3'-pyrrolidinyl spirooxindole diastereomers could be obtained in excellent enantioselectivities (up to 99% ee).
Subject(s)
Indoles/chemistry , Pyrrolidines/chemistry , Amines/chemistry , Catalysis , Crystallography, X-Ray , Cyclization , Indoles/chemical synthesis , Molecular Conformation , Quinine/chemistry , Stereoisomerism , Thiourea/chemistryABSTRACT
An effective double Michael reaction has been disclosed to access spirocyclic oxindoles in high yields (up to 98%) and excellent enantioselectivities (up to 98% ee).