Stereoselective Aza-Henry Reaction of Chiral tert-Butanesulfinyl Imines with Methyl or Ethyl 4-Nitrobutanoate: Easy Access to Enantioenriched 6-Substituted Piperidine-2,5-diones

The base-catalyzed addition of 4-nitrobutanoates 6 to N-tert-butanesulfinyl imines 8 under solvent-free reaction conditions proceeded with high face diastereoselectivity. The resulting β-nitroamine derivatives 9 were easily transformed into 6-substituted piperidine-2,5-diones 11 upon removal of the sulfinyl group with concomitant δ-lactam formation and functional group transformation under Nef reaction conditions.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (Grant Nos. CTQ2011-24165, and Consolider Ingenio 2010-CSD-2007-00006), the Generalitat Valenciana (Grant No. PROMETEO/2009/039 and FEDER) and the University of Alicante. M.J.G.M. thanks the University of Alicante for a predoctoral fellowship