Highly efficient asymmetric vinylogous Mannich reaction induced by O-pivaloylated D-galactosylamine as the chiral auxiliary.

Carbohydrates as Chiral Templates : Stereoselective Synthesis of ( R ) - and ( S ) - ~ - Aminophosphonic Acid Derivatives

The stereoselective synthesis of diethyl (S)or (R)-IX-[( O-pivaloylhexapyranosyl)amino]benzylphosphonates is achieved via Lewis acid catalyzed addition of diethyl phosphite to O-pivaloylated Nbenzylidene-{3-D-galactosylamine or N-benzylidene-IX-D-arabinopyranosylamine. The process can also be performed by a one-pot procedure selectively giving (S)-aminophosphonic acid derivatives from galactosy...

An Efficient and One-pot Procedure for the Synthesis of Chiral Isoxazolidine via Catalytic Highly Enantioselective 1,3-dipolar cycloaddition

Synthesis of enantiomerically pure isoxazolidine via an asymmetric 1,3- dipolar cycloaddition reaction of nitrone with electron-deficient dipolarophile was described. The process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendate bis(imine)–Cu(II)triflate complex as catalyst. The reaction mechanism is discussed on the basis of the assignment of t...

A highly efficient and practical method for catalytic asymmetric vinylogous Mannich (AVM) reactions.

Merging chiral organocatalysts: enantio- and diastereoselective direct vinylogous Mannich reaction of alkylimines.

An enantio- and diastereoselective direct vinylogous Mannich reaction of alpha,alpha-dicyanoolefins and N-sulfonyl alkylimines has been developed by the catalysis of a new family of bifunctional organocatalysts merging chiral BINOL and 9-amino-9-deoxyepi-cinchona alkaloid skeletons, from which chiral beta-, delta- or gamma-amino compounds could be efficiently derived.

Regioselectivie Synthesis of New Spiro-Oxindolopyrrolidines via a Three-Component Asymmetric 1,3-Dipolar Cycloaddition Reaction of Azomethine Ylides aAnd Chiral Menthyl Cinnamate

An efficient, one-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,wit...