Manganese-catalyzed nucleophilic addition of aldehydes to carbonyl compounds via hydrazone umpolung on water

Abstract

Hydrazones as organometallic equivalents have emerged as a general and sustainable strategy to utilize naturally abundant aldehydes and ketones as feedstocks while only releasing water and nitrogen gas as byproducts. Yet the addition of these carbanion equivalents to carbonyl compounds has been limited to the use of precious metals as catalysts and hazardous solvents under an inert atmosphere. Herein, we report the development of a manganese-based catalyst system for the addition of aldehydes to carbonyl compounds producing secondary and tertiary alcohols with yields of up to 91%. Furthermore, this method has proven robust and reproducible under aqueous and aerobic conditions to employ an earth-abundant metal catalyst, hence advancing hydrazone umpolung chemistry to be more sustainable and operationally simple.