An approach to the synthesis and assignment of the absolute configuration of all enantiomers of ethyl hydroxy(phenyl)methane(P-phenyl)phosphinate

Ethyl butyryloxy(phenyl)methane(P-phenyl)phosphinate was hydrolyzed using four bacterial species as biocatalysts. In all cases the reaction was stereoselective and isomers bearing an α-carbon atom with an (S)-configuration were hydrolyzed preferentially. Also a lack of stereoselectivity toward the phosphorus atom was observed. Hydrolysis of one enantiomeric mixture, namely mixture of (SP,R) and (RP,S) configuration afforded enantiomerically pure ethyl (RP,S)-hydroxy(phenyl)methane(P-phenyl)phosphinate, configuration of which was established by X-ray crystallography. The observed 1H and 31P NMR chemical shifts of Mosher esters of ethyl hydroxy(phenyl)methane(P-phenyl)phosphinate were correlated with the configurations of both stereogenic centers of all four stereoisomers.

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Ethyl hydroxy(phenyl)methane(P-phenyl)phosphinateC15H17O3PEe = 87%[α]D23=+2.8 (c 1.67, CH3Cl, 23 °C)Source of chirality: kinetic resolutionAbsolute configuration: (RP,S)