Organic Letters 2010-11-19

One-pot enantioselective syntheses of iminosugar derivatives using organocatalytic anti-michael-anti-aza-Henry reactions.

Ritsuo Imashiro, Hisatoshi Uehara, Carlos F Barbas

Index: Org. Lett. 12(22) , 5250-3, (2010)

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Abstract

Organocatalyst-controlled asymmetric anti-Michael reactions of (tert-butyldimethylsilyloxy)acetaldehyde with a range of nitroolefins, followed by an intermolecular aza-Henry reaction with imine, provided iminosugar derivatives with five contiguous stereocenters in very high enantiomeric excess in one pot. The stereochemistry of the aza-Henry reaction was substrate controlled and is explained by a six-membered cyclic transition-state model.