An exceptionally stereoselective and general synthesis of (Z)-α-haloacrylates, ready to undergo various synthetic transformations, has been demonstrated from α-haloacetates and aldehydes in a one-pot manner via the titanium-enolate based asymmetric aldol condensation. Besides being an expedient synthetic procedure, the ready availability of diverse α-haloacetates, exceptional stereoselectivity, and high yields make the process a versatile transformation in organic synthesis. The potential of this method in up-scaling operations has been illustrated.
Biocatalyzed Enantioselective Reduction of Activated C=C Bonds: Synthesis of Enantiomerically Enriched α-Halo-β-arylpropionic Acids
作者:Elisabetta Brenna、Francesco G. Gatti、Alessia Manfredi、Daniela Monti、Fabio Parmeggiani
DOI:10.1002/ejoc.201100537
日期:2011.7
The enantioselective biocatalyzed reduction of the C=C bond of some (Z)-methyl α-halo-β-arylacrylates was investigated. The reaction was performed by baker'syeast fermentation and Old Yellow Enzymes 1–3 mediated biotransformations. The final products were, respectively, enantiomerically enriched (S)-α-halo-β-arylpropionic acids and their methyl esters, and ester hydrolysis was promoted in the whole