Catalytic asymmetric Michael and Mannich-type reactions of glycine Schiff hases with chiral two-center organocatalysts, tartrate-derived diammonium salts (TaDiASs), are described. On the basis of conformational studies, optimized TaDiASs with a 2,6-disubstituted cyclohexane spiroacetal were newly designed. These TaDiASs catalyzed the asymmetric Michael and Mannich-type reactions of glycine Schiff bases with higher enantioselectivity than previous catalysts. In the Mannich-type reaction, aromatic N- Boc-protected imines (Boc = tert-butoxycarbonyl) as well as enolizable alkyl imines were applicable. As a synthetic application of the catalytic asymmetric Mannich-type reaction with the optimized TaDiASs. we developed a catalytic asymmetric total synthesis of (+)-nemonapride, which is an antipsychotic agent.
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