Selective reductive α-methylation of chalcone derivatives using methanol

• Published in: Journal of catalysis 2022-10, Vol.414, p.225-235
• Main Authors: Sau, Anirban, Panja, Dibyajyoti, Dey, Sadhan, Kundu, Rahul, Kundu, Sabuj
• Format: Article
• Language: English
• Subjects: Chemoselective; Methanol activation; Reductive methylation; α,β-unsaturated ketones
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2022.08.035

[Display omitted] •An efficient tandem, chemoselective reductive methylation of α,β-unsaturated ketones is reported using methanol.•An electron rich, new Ir(III) complex is employed for this transformation with very low catalyst loading (0.05-0.1 mol%).•Practical applicability of the protocol is demonstrated with a wide variety of substrate scopes.•To understand this catalytic process, several kinetic studies and detailed DFT calculations were carried out. An electron rich, new co-operative iridium(III) complex catalysed tandem conversion of α,β-unsaturated ketones to the α-methylated ketones is described using methanol. Employing this chemoselective protocol, reductive methylation of a wide range of chalcone derivatives, variety of aryl and aliphatic fragment containing α,β-unsaturated ketones along with few biologically important molecules were effectively carried out. Several control experiments, kinetic studies, Hammett study, and DFT calculations were accomplished to comprehend this co-operative iridium(III) catalysed tandem reductive methylation of α,β-unsaturated ketones.