IN233623: A stereoselective chemoenzymatic process for the preparation of optically enriched phenylglycidates alkyl(2S,3R) - phenylglycidate and alkyl(2R,3S)- phenylglycidate as precursors of taxol side chain

The invention relates to a stereoselective chemoenzymatic process for the preparation of optically enriched phenylglycidates i.e. alkyl(2S,3R)-phenylglycidate and alkyl(2R,3S)-phenylglycidate as precursors of taxol side chain. The process involves preparation of halohydrins from alkyl cinnamates by the action of a halogenating agent followed by their conversion to alkyl acylates, incubating alkyl acylates with dry powder of lipase from Aspergillus niger. Separation of hydrolyzed halohydrins, acid followed by base catalyzed reaction for the cyclization of resolved esters. There are a number of reports on the preparation of these chiral intermediates by biochemical or chemoenzymatic methods besides asymmetric synthesis. No prior art discloses the application of lipase from Aspergillus niger for the preparation of (2S,3R)-phenylglycidate and alkyl(2R,3S)-phenylglycidate.