A Mild and Chemoselective Hydrosilylation of α-Keto Amides by Using a Cs2CO3/PMHS/2-MeTHF System

A Cs2CO3-catalyzed hydrosilylation reaction of alpha-keto amides that proceeds through the in situ formation of MeSiH3 has been developed by using inexpensive polymethylhydrosiloxane in 2-methyltetrahydrofuran (2-MeTHF) as the solvent. A wide range of aryl and alkyl alpha-keto amides, prepared from anilines and alkylamines, were subjected to the hydrosilylation conditions to afford alpha-hydroxy amides in moderate to excellent yields. This transition-metal-free protocol was applied to a chemoselective hydrosilylation, in which reduction occurred at the carbonyl of the alpha-keto amide functionality over that of the simple ketone, and further extended to a gram-scale protocol.