Green Synthesis and Theoretical Study of β‐Amino Esters via PPh₃‐Catalyzed Mannich Reaction

Abstract

A new, efficient and simple method was designed for the synthesis of novel β‐carbonyl ester derivatives by using the PPh3‐catalyzed one‐pot method, three‐component condensation from aryl amines, aryl aldehydes and dicarbonyl ester under solvent‐free conditions. The comparative results from syntheses under these conditions provide a very simple reaction procedure that produces excellent yields and high stereoselectivity, avoids column chromatographic separation and provides an easy aqueous work‐up compared with the conventional reaction. DFT calculations were utilized to confirm and understand the mechanism of the PPh3‐catalyzed Mannich reaction. Detailed analysis of the two‐reaction pathway and their energy difference proves the stereo‐selectivity effect of the Mannich reaction, favouring anti‐isomer formation.

Synthesis of imidazo[1, 2‐a]pyridines via the silver acetate‐catalyzed Groebke‐Blackburn‐Bienayme reaction with ethylene glycol as a biodegradable and sustainable solvent

“…This new protocol has unique features due to green reaction conditions, nontoxic, economical catalyst, reduced pollution, and operational simplicity. In continuation of our research program on the development of MCRs with a greener method, herein, we develop the green synthesis of 3‐aminoimidazo‐fused heterocycles via the GBBR by using 2‐amino substituted heterocycles, aldehydes, and isocyanides with AgOAc catalyst having coordination capability with unsaturated bonds and activate isocyanide (NC) . Furthermore, EG was used as the promoter, with a high boiling point, low viscosity, high specific energy, and easily miscible with many other organic solvents …”

H3PW12O40 Anchored on the Three-Dimensional and Networked SBA-15 as an Efficient and Recyclable Catalyst for Mannich Reaction

“…Mannich reaction is an important reaction to produce β-amino carbonyl compounds, which can be catalyzed by some acidic catalysts. However, these strategies suffer from several shortcomings, such as low yields [6], long reaction times [7], and the use of environmentally unfriendly solvents [8]. Therefore, there is high interest in developing new catalysts to overcome the drawbacks of the classical methods [9].…”