Organocatalytic Vinylogous Michael Additions

Significance

The catalytic enantio-, diastereo- and γ-selective Michael addition of β-substituted cyclohexenones to nitroalkenes and nitrostyrenes is reported. The catalytic concept relies on the dien­amine formation of amino salt 1 with the carbonyl compound, enabling nucleophilic attack on the nitro­alkene from the exo-γ position. Possible side products arising from an endo-γ or crossed dien­amine α-attack to the electrophile are not observed. Furthermore, the reported method enabled the construction of quaternary stereocenters since β,β-disubstituted nitrostyrenes and α-methyl cinnamates could be transformed into the corresponding Michael products equally well.