Recent Advances in Base-assisted Michael Addition Reactions

Abstract

The Michael addition is an important, highly efficient, and atom-economical method for the diastereoselective and enantioselective C-C bond formation. MA used in the synthesis of natural products and drugs is tandem sequenced reactions. An important tandem sequence of Michael and Aldol additions is the Robinson annulation. MA is a versatile reaction employed for efficient bond formation between electron-poor olefins as Michael acceptors with varied nucleophiles as Michael donors. Apart from being involved in C-C bond formation, MA is also employed in the formation of C-X bond (X=O, N, S, P etc.) giving rise oxa-, aza-, thia-, phospha-Michael addition products. In recent years many articles have been published on MA. The mechanism of MA gives an insight into the reaction is initiated by the base. The present review provides comprehensive information on recent advancements in base-assisted Michael addition reactions including varied organic and inorganic bases, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,4-Diazabicyclo[2.2.2]octane (DABCO), 4-dimethylaminopyridine (DMAP), triethylamine (Et3N), tributylamine (Bu3N), N,N-diisopropylethylamine (DIEPA), diethylamine (NHEt2), guanidine derivatives, and bifunctional thiourea. A variety of inorganic bases including metal alkoxides, metal acetates, metal hydroxides, metal hydrides, metal carbonates, metal halides, and triphenylphosphine (TPP) can also be successfully used in Michael reactions.

Hydrotalcite-based catalysts for 1,4-conjugate addition in organic synthesis

“…3 It results in a new carbon-carbon, carbon-nitrogen, carbon-oxygen, or carbonsulfur bond through the addition of nucleophiles to acceptor substituted double and triple bonds in this reaction. Numerous well-known reactions, including the Bohlmann-Rahtz pyridine synthesis, 4 Michael addition, 5 Robinson annulation, 6 Stork enamine reaction, 7 Nagata hydrocyanation, 8 Giese radical addition, 9 etc., are based on the conjugate addition concept, recognizing its significance in organic chemistry. Consequently, enough progress was observed in this field, which was summarised in several review articles.…”