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Free keywords:
aldehydes; diastereoselectivity; enantioselectivity; Mannich reaction; organocatalysis
Abstract:
Double‐cross: Proline catalyzes the double Mannich reaction of acetaldehyde with N‐Boc imines in excellent yields (up to 99 %; Boc=tert‐butoxycarbonyl) and close to perfect diastereo‐ and enantioselectivities. Depending on the choice of catalysts, both the chiral, pseudo‐C2‐symmetric diastereomer and the corresponding meso compound can be prepared. Cross double Mannich reactions of acetaldehyde with two different imines are also demonstrated.