Although the reaction of dienolate (1) with aldehydes is frequently lacking in regio- and diastereo-selectivity, the γ-tin substituted derivatives (5), easily obtainable from (1), give (3) and (4) diastereoselectively by controlling the reaction conditions.
Stabilization and activation of dienolates with germanium and tin. Stereo- and regioselective aldol reactions, regioselective coupling reactions, and regioselective synthesis of amino acid derivatives