HIGHLY DIASTEREOSELECTIVE COUPLING REACTIONS BETWEEN CHIRAL BENZALDEHYDE TRICARBONYLCHROMIUM COMPLEXES AND ACTIVATED DOUBLE-BONDS

The amine catalyzed coupling reaction of acrylic derivatives with benz aldehydes (Baylis-Hillman reaction) is more efficient when the arene i s complexed to the electrophilic Cr(CO)3 group. Reactions with planar chiral o-substituted benzaldehyde complexes are highly diastereoselect ive. 3-Hydroxy-2-methylenealkanoic acid derivatives can be obtained ef ficiently and with very high enantiomeric excess from readily accessib le enantiomerically pure complexes. The configuration of the benzylic stereogenic center relative to the planar chirality of the arene compl ex was determined in one case by an X-ray structural analysis. The rea ction has been extended to an o-anisaldehydeimine complex.