Stereoselective synthesis of (Z)-alpha-haloacrylic acid derivatives, and (Z)-haloallylic alcohols from aldehydes and trihaloesters or amides promoted by Rieke manganese.

A Mn*-promoted sequential process directed toward the synthesis of (Z)-alpha-halo-alpha,beta-unsaturated esters or amides is described. In both cases, the process takes place with complete Z-stereoselectivity. In addition, (Z)-alpha-chloro-alpha,beta-unsaturated ketones and carboxylic acids, and (Z)-haloallylic alcohols were readily prepared from (Z)-alpha-halo-alpha,beta-unsaturated amides derived from morpholine, or esters. A mechanism has been proposed to explain the sequential process and the stereoselectivity observed.