Chloramphenicol base chemistry. Part 11: chloramphenicol base-derived thiourea-catalyzed enantioselective Michael addition of malononitrile to α,β-unsaturated ketones

Abstract

The first chloramphenicol base-derived thiourea-catalyzed enantioselective Michael addition of malononitrile to α,β-unsaturated ketones is reported. The Michael adducts were obtained in good to excellent yields (up to 98% yield) and enantioselectivities (up to 94% ee). This reaction has a broad substrate scope to various α,β-unsaturated ketones. With this in mind, this methodology was successfully applied to the synthesis of a chiral piperidone, an advanced building block for dihydropyridinone P2X7 receptor antagonists.