A general organocatalytic enantioselective malonate addition to alpha,beta-unsaturated enones.

A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to alpha,beta-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic enones can be used and the reaction with ethyl malonates 3 b provides the Michael addition products in high yields with good to excellent enantioselectivities.

Diastereoselective aldol reactions with butane-2,3-diacetal protected glyceraldehyde derivatives.

Diastereoselective aldol coupling reactions with butane-2,3-diacetal (BDA) protected glyceraldehyde derivatives are reported. Good selectivities of up to 20:1 for the homologated aldol products have been achieved in preparatively useful yields.

Asymmetric organocatalytic conjugate addition of malonates to enones using a proline tetrazole catalyst.

5-Pyrrolidin-2-yltetrazole performs as a useful organocatalyst for the asymmetric addition of malonates to a range of enones, with good to excellent enantioselectivities.

The use of a continuous flow-reactor employing a mixed hydrogen-liquid flow stream for the efficient reduction of imines to amines.

Imines have been reduced to amines in high yield, and with excellent chemoselectivity, by catalytic hydrogenation in a continuous flow-reactor, utilising an electrochemically-generated hydrogen source to produce a mixed hydrogen-liquid flow stream.

A chiral molecular recognition approach to the formation of optically active quaternary centres in aza-Henry reactions.

An approach to asymmetric catalysis based on chiral molecular recognition by the combination of chiral Lewis acids and chiral organocatalysis for the formation of optically active quarternary centers in the aza-Henry reaction is presented; this procedure leads to products with up to 98% ee and a diastereomeric ratio of 14 : 1 in excellent yields with catalyst loadings of 5 mol%.

Mimicking enzymatic transaminations: attempts to understand and develop a catalytic asymmetric approach to chiral alpha-amino acids.

Attempts are made to build a bridge between asymmetric catalysis and enzymatic reactions by mechanistic investigations and the development of a catalytic and enantioselective approach to amination of alpha-keto esters by primary amines catalyzed by chiral Lewis acids as a model for transamination enzymes. Different Lewis acids can catalyze the half-transamination of alpha-keto esters using primary amine nitrogen sources such as pyridoxamine and 4-picolylamine. The mechanistic studies of the Lewis-acid catalyzed half-transamination using deuterium-labelled compounds show the incorporation of deuterium atoms in several positions of the alpha-amino acid derivative, indicating that the enol of the alpha-keto ester plays an important role along the reaction path.

Catalytic enantioselective transamination of alpha-keto esters: an organic approach to enzymatic reactions.

The half-transamination reaction of alpha-keto esters with pyridoxamine or 4-picolylamine was found to be catalysed by different metal catalysts in organic solvents giving moderate yields and enantioselectivities of up to 37% ee for methyl-3-indole pyruvate.