STEREOCHEMICALLY PURE ALLYLMETALS - AN APPLICATION TO DIASTEREOSELECTIVE GAMMA-ALLYLATION OF ALDEHYDES

A new methodology, the preparation of stereochemically homogeneous all ylic metals (Mg and Ba) from the corresponding allylic chlorides, was successfully applied to a diastereoselective gamma-allylation reaction of aldehydes using B-methoxy-9-borabicyclo[3.3.1]nonane (B-OMe-9-BBN) as an additive. Using this method, threo-homoallylic alcohols were se lectively obtained from (E)-allylic metal compounds and erythro-isomer s from (Z)-allylic metal compounds in high yields.