Copper-Catalyzed Hydroboration of Enamides with Bis(pinacolato)diboron: Promising Agents with Antimicrobial Activities

Abstract

We reported in this study the hydroboration of enamides in methanol at room temperature catalyzed by copper complexes. Under such conditions, a Gram-scale reaction with a high yield was also completed. Hydroboration of 3-methylene, 2-(alkyl and phenylisoindolin-1-one 5 with bis(pinacolato)diboron yields the respective compounds 6 in good yields with high-to-moderate enantioselectivity (58% ee). Furthermore, the antimicrobial properties of the synthesized compounds were tested against four indicator microorganisms: the two Gram-positive bacteria L. monocytogenes ATCC 1911 and S. aureus ATCC 6538, the Gram-negative bacterium S. typhimurium ATCC 14028, and the fungus C. albicans (ATCC 90028). The MIC values of compounds 5-6 range from 0.312 to 2.5 (μg/mL) against L. monocytogenes, from 2.1 to 0.136 (μg/mL) against S. aureus, and from 0.126 to 0.923 (μg/mL) against S. typhimurium.