A rhodium-catalysed Sonogashira-type coupling exploiting C-S functionalisation: orthogonality with palladium-catalysed variants.

Milan Arambasic,Manjeet K Majhail,Michael C Willis,Robert N Straker,James D Neuhaus

doi:10.1039/c9cc00092e

Abstract

This report concerns the development of an efficient Sonogashira-type coupling of arylmethylsulfides and terminal alkynes to generate aryl alkyne motifs. Orthogonal reactivity between traditional Pd catalysts, and the Rh catalysts employed, results in the ability to selectively activate either the C-S bond or C-X bond through catalyst choice. The Rh-bisphosphine catalyst has further been shown to be able to effect a hydroacylation-Sonogashira tandem sequence, and in combination with further onward reactions has been used in the synthesis of heterocycles and polycyclic systems.

Highlights

This report concerns the development of an efficient Sonogashiratype coupling of arylmethylsulfides and terminal alkynes to generate aryl alkyne motifs
The Rh–bisphosphine catalyst has further been shown to be able to effect a hydroacylation-Sonogashira tandem sequence, and in combination with further onward reactions has been used in the synthesis of heterocycles and polycyclic systems
A number of laboratories have looked at using C–H functionalisation chemistry to overcome this problem with some success, the use of simple terminal alkynes as the coupling partner remains rare,[6] with haloalkynes,[7] or hypervalent iodine reagents[8] being the reagents of choice in ‘‘inverse Sonogashira coupling reactions’’

Summary

Introduction

This report concerns the development of an efficient Sonogashiratype coupling of arylmethylsulfides and terminal alkynes to generate aryl alkyne motifs. The Rh–bisphosphine catalyst has further been shown to be able to effect a hydroacylation-Sonogashira tandem sequence, and in combination with further onward reactions has been used in the synthesis of heterocycles and polycyclic systems.

Results

Conclusion