L-Proline Derived Bifunctional Organocatalysts: Enantioselective Michael Addition of Dithiomalonates to trans-β-Nitroolefins

A series of novel L-proline derived tertiary amine bifunctional organocatalysts 9 are reported, which were applied to the asymmetric Michael addition of dithiomalonates 2 to trans-β-nitroolefins 1. The reaction proceeded in high yields (up to 99%) with high enantioselectivities (up to 97% ee). The synthetic utility of this methodology was demonstrated in the short synthesis of (R)-phenibut in high yield.

Organocatalytic asymmetric Michael addition of aldehydes and ketones to nitroalkenes catalyzed by adamantoyl l-prolinamide

A series of adamantoyl l-prolinamides have been synthesized.

Synthesis of γ-nitroaldehydes containing quaternary carbon in the α-position using a 4-oxalocrotonate tautomerase whole-cell biocatalyst

Synthetically valuable quaternary carbon containing γ-nitroaldehydes were obtained from branched chain aldehydes and a range of α,β-unsaturated nitroalkenes by a whole-cell biocatalytic reaction using 4-oxalocrotonate tautomerase as catalyst.

Promiscuous catalysis of asymmetric Michael-type additions of linear aldehydes to β-nitrostyrene by the proline-based enzyme 4-oxalocrotonate tautomerase

Exploiting catalytic promiscuity: The proline-based enzyme 4-oxalocrotonate tautomerase (4-OT) promiscuously catalyzes asymmetric Michael-type additions of linear aldehydes--ranging from acetaldehyde to octanal--to trans-β-nitrostyrene in aqueous solvent. The presence of 1.4 mol% of 4-OT effected formation of the anticipated γ-nitroaldehydes in fair to good yields with dr values of up to 93:7 and ee values of up to 81 %.