Polymer-supported manganese-catalysed transformation of esters and aldehydes to alcohols

Abstract

Compared to precious metals, manganese has emerged as a more earth-abundant and potentially safer metal to catalyse important chemical transformations. In contrast to homogeneous Mn catalysts, the use of heterogeneous Mn catalysts, is rare. Herein we describe the preparation of a Mn catalyst supported on a simple phosphine-containing polymer, that efficiently provides alcohols from esters and aldehydes, and facilitates the reduction of amides. Surprisingly, the catalyst gave improved yields upon recycling, which prompted a short study into the structural and oxidative changes of the catalyst using SEM-EDX and XAFS. Breakage of the microspheres and increased Mn oxidation states were observed upon recycling. Ultimately a priming procedure was developed that enabled direct procurement of an active and viable catalyst system.