Reactivity of Methyl Mandelate-Ti(IV)-enediolate: Oxidative Homocoupling versus Aldol and DirectMannich-Type Syn-Diastereoselective Condensation

摘要

Methyl mandelate undergoes quantitative oxidative homo-coupling on treatment with TiCl_4/amine at room temperature. In the presence of ArCHO, quantitative syn-diastereo-selective aldol condensation takes over the dimerization, whereas exclusive Mannich-type syn-diastereoselective reaction is observed in the presence of both ArCHO and PhNH_2. The subsequent reactions of the title intermediate do not depend on how it is generated.