Stereoselective Organocatalytic One-Pot α,α-Bifunctionalization of Acetaldehyde by a Tandem Mannich Reaction/Electrophilic Amination

The first asymmetric organocatalyzed one-pot alpha,alpha-bifunctionalization of acetaldehyde with two different electrophiles is described. A diarylprolinol silyl ether-catalyzed reaction of acetaldehyde with an imine and di-tert-butyl azodicarboxylate affords syn-2,3-diaminoalcohols with excellent ee values of up to 98%. This methodology was successfully applied to the synthesis of a chiral alpha,beta-diaminocarboxylic acid.