Microwave heating and conventionally-heated continuous-flow processing as tools for performing cleaner palladium-catalyzed decarboxylative couplings using oxygen as the oxidant – a proof of principle study

Abstract

A microwave unit interfaced with a gas-loading accessory is used as a tool for facilitating the palladium-catalyzed decarboxylative Heck reaction of 2,6-dimethoxybenzoic acid and methyl acrylate, using molecular oxygen as the oxidant. The reaction is complete in less time and at a lower catalyst loading than when using conventional approaches. The reaction is scaled up using continuous-flow processing, employing a reactor in which both gas input and heating can be performed simultaneously. An 86% isolated product yield is obtained. This proof-of-principle study paves the way for the technology to be used in other cases of these increasingly popular decarboxylative coupling reactions.

Keywords

• decarboxylative coupling
• flow chemistry
• microwave heating