One-Pot Synthesis of Aza-Morita-Baylis-Hillman Adducts via Zinc-Mediated Allylation of 4-Bromocrotonates and Imines

Abstract

An approach to the synthetically valuable β-substituted aza-Morita–Baylis–Hillman (MBH) type products, through zinc-mediated allylation of imines with 4-bromocrotonates followed by subsequent isomerization of the double bond, was developed. Complementary to classical MBH reaction, this reaction utilizes easily available 4-bromocrotonates as the reaction partners, providing a rapid alternative to the traditional use of α,β-unsaturated carbonyl compounds. The short reaction time, one-pot operation, broad substrate scopes, gram-scale synthesis, and synthetic application exemplified the utility and practicability of this method.

Novel Synergistic Catalysis by Ethylcarbodiimide Hydrochloride Salt and CuI Towards Morita‐Baylis‐Hillman Reaction

“…[8] Accordingly, various methods have been developed for the synthesis of MBH adduct using different catalysts/catalyst systems viz. trimethylamine, [9] DABCO in ionic liquid, [10] TTMPP, [11] transition metal catalyst, [12][13][14] Lewis acid, [15][16][17][18] Lewis base, [19][20][21][22][23][24][25] organometallic catalyst, [26] organocatalyst [27][28][29][30][31] etc. However, the inverse environmental impact of catalysts like transition metal catalysts, toxicity and availability issue of ILs, [32] obtaining of racemic products, leaching of metal during the course of reaction and difficulties in the preparation of the organometallic catalysts, use of N 2 atmosphere, use of acid as an additive, long reaction time, poor yield and high reaction temperature in some cases of the above-reported methods still demand the search of new catalytic routes for this venerable reaction.…”