A tandem reduction of primary amines, carbonyl compounds, CO2, and boranes catalyzed by in situ formed frustrated Lewis pairs?

Organic Chemistry Frontiers Pub Date: 2022-07-26 DOI: 10.1039/D2QO00504B

Abstract

2-Aminothiazole in combination with a borane?trimethylamine complex exhibits efficient catalytic activity for four-component reductive methylation of primary amines, carbonyl compounds, boranes, and CO2 (1 atm) under metal-free conditions. A wide range of highly functionalized tertiary N-methylamines are efficiently synthesized in one pot. In particular, multicomponent reductive reactions involving less reactive ketones are realized for the first time. This protocol is also applicable to the gram-scale synthesis of butenafine and late-stage modifications of several drugs. Mechanistic studies and DFT calculations indicate that an intramolecular FLP-type catalyst is generated and serves as the key for CO2 activation.

Graphical abstract: A tandem reduction of primary amines, carbonyl compounds, CO2, and boranes catalyzed by in situ formed frustrated Lewis pairs
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