Phase-transfer-catalyzed asymmetric aza-Henry reaction using N-carbamoyl imines generated in situ from α-amido sulfones

(Chemical Equation Presented) A general approach to the catalytic asymmetric aza-Henry reaction has been developed. The combination of a commercially available phase-transfer catalyst (PTC) with a base is able to promote the in situ formation of N-carbamoyl imines from α-amido sulfones and activate nitromethane towards the asymmetric addition reaction, thus furnishing N-carbamoyl-protected β-nitroamines in good yields and with up to 98% ee (see scheme; PG = protecting group). © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.