Carbonyl-Catalyzed Biomimetic Asymmetric Mannich Reaction

Key words

carbonyl catalysis - Mannich reaction - pyridoxal - α,β-diamino acid esters

Significance

The Zhao group reports the activation of primary amines by carbonyls. Using an N-quaternized pyridoxal catalyst for the direct asymmetric Mannich reaction of glycinate with aryl N-diphenylphosphinyl imines, α,β-diamino acid esters were obtained in good yields and excellent stereoselectivities.

Comment

Based on their recently developed chiral pyridoxal and pyridoxamine catalysts for transamination reactions (J. Am. Chem. Soc. 2016, 138, 10730), the authors developed a catalyst that activates primary amines through carbonyl catalysis. In contrast to other α-functionalizations of primary amines, this fascinating catalysis strategy does not require protecting-group manipulation.