Cyclic alkyl phosphino carbenes – a synthetic investigation

Abstract

A proposed synthetic pathway to produce a cyclic (alkyl)(phosphino) carbene (CAPC)has been investigated. 1-bromo-2,4,6-tritertbutylbenzene (-2,4,6-tritertbutylbenzene =mes*) was used to produce Mes*PCl₂. A ring closure to form a phosphacycle was performed, a methyl group was added to the phosphorus and was reacted with <em>N</em>-bromosuccinimide to form the carbene precursor. The purpose for this synthesis is to attempt to replicate CAACs and improve their properties by replacing nitrogen with phosphorus. A less sterically bulky approach was done using only one <em>ortho</em> tBu to allow the use of more sterically bulky substituents at phosphorus. This synthesis provides a start to synthesizing the first CAPC.