Morita–Baylis–Hillman, Vinylogous Morita–Baylis–Hillman, and Rauhut–Currier Reactions

Recent advances in the synthetic applications of Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

“…RC 7 and MBH 8 reactions are significant in organic synthesis because these reactions enable the coupling between two electron-deficient molecules. Several alkenes were employed in these classical reactions, including acrylic esters, acrylonitriles, vinyl ketones, vinyl sulfones, etc .…”

Catalyst- and Base-Free Synthesis of Morita–Baylis–Hillman and Rauhut–Currier Adducts of β-Aminonitroalkenes

“…Rauhut–Currier (RC) and Morita–Baylis–Hillman (MBH) reactions are important organic transformations because they enable the coupling between two electron-deficient molecules in the absence of any metal but usually in the presence of a nucleophilic Lewis base catalyst. Rauhut and Currier, in 1963, reported the dimerization of electron-deficient alkenes catalyzed by organophosphines .…”

“…Later, several electrophiles such as aldehydes, imines, azodicarboxylates, vinyl ketone, vinyl sulfone, vinyl esters, in situ generated imines, etc ., were used in MBH and RC reactions of nitroalkenes. , The MBH and RC adducts of nitroalkenes thus obtained have also been found to possess significant biological properties − as well as useful in the construction of various drugs and natural products . However, in many MBH and RC reactions, the use of stoichiometric amounts of nucleophilic bases such as DABCO, DMAP, quinuclidine, phosphine, etc ., was necessary for the complete conversion of the starting material(s) which was less appealing. ,, Therefore, reagent- and catalyst-free synthesis of MBH and RC adducts via modification of substrate(s) and/or reaction conditions is of keen interest from the perspective of synthetic efficiency and sustainability. Incidentally, Nemes et al reported the reaction of 2-nitromethylene-pyrrolidine with di- and tricarbonyl compounds and a one-pot reaction with glyoxylate and aniline with limited substrate scope .…”

“…In 1972, a similar transformation was reported by Baylis and Hillman using DABCO as the catalyst . Several alkenes and electrophiles were used in these reactions thereafter, including conjugated ketones, esters, sulfones, acrylates, etc . , In 2004, for the first time, our group reported the MBH reaction of conjugated nitroalkenes using formaldehyde as the electrophile to synthesize various α-hydroxymethylated nitroalkenes . Later, several electrophiles such as aldehydes, imines, azodicarboxylates, vinyl ketone, vinyl sulfone, vinyl esters, in situ generated imines, etc ., were used in MBH and RC reactions of nitroalkenes. , The MBH and RC adducts of nitroalkenes thus obtained have also been found to possess significant biological properties − as well as useful in the construction of various drugs and natural products .…”