Grignard reagents-catalyzed hydroboration of aldehydes and ketones

• DOI: 10.1016/j.tet.2020.131145
• Publication Date: 2020-03-17T10:58:00Z
• Authors: Weifan Wang; Kai Lu; Yi Qin; Weiwei Yao; Dandan Yuan; Sumod A. Pullarkat; Li Xu; Mengtao Ma
• Keywords: Hydroboration; Chemoselectivity; Boranes; Functional group; Stoichiometry

Abstract Simple, commercially available Grignard reagents have been used as highly efficient precatalysts for the hydroboration of a wide range of aldehydes and ketones. The reaction employs very low catalyst loadings (aldehydes: 0.05 mol%, ketones: 0.5 mol%), and proceeds rapidly (aldehydes: 10 min, ketones: 20 min) under neat condition at room temperature. The Grignard reagent catalyst demonstrated good substrate scope, functional group tolerance, and high chemoselectivity in the carbonyl hydroboration. DFT calculations were performed to investigate the possible reaction mechanism. In contrast to the traditional stoichiometric use of Grignard reagents, this newly developed protocol provides a catalytic application of these reagents for molecular transformations.