Innovative catalysis in Michael addition reactions for C-X bond formation

The Michael addition reaction is one of the most classical reactions in organic synthesis as it is widely applied to synthesis of C-X (XC, = O, N, S) bonds to produce natural compounds, and drugs. It covers a nucleophilic addition to alpha, beta-unsaturated carbonyl compound using a carbanion or another nucleophile and deals with larger class of conjugate additions. In this review, we have explored different important Michael acceptors such as nitroolefins, alpha,beta-unsaturated carbonyl compounds, imides, etc. for asymmetric organocatalytic Michael reactions. It covers reports on organocatalysts based on ferrocene, amine, pyrrolidine, etc. and heterogeneous catalysts based on metal oxides with all pros and cons. Future scope is also delineated.