Stereoselective Synthesis of Functionalized Chiral 2-Nitrocyclohexanecarboxylic Esters via Catalytic Dienamine Addition to beta-Substituted beta-Nitroacrylates

A metal-free stereoselective catalytic addition of in situ generated dienamine to -nitroacrylates has been developed. Starting from simple ,-unsaturated ketones, highly functionalized chiral -nitrocyclohexanecarboxylic esters were obtained in a single step, in good yields and up to 98% ee. By an unprecedented mechanistic pathway, starting from the synthetically readily available E-nitroacrylate, the present methodology allowed us to obtain as major product the isomer bearing a cis relative disposition between the nitro and the ester groups, which is not accessible via a classical Diels-Alder reaction.