Palladium-Catalyzed Direct Arylation of Selenophene

Paulo H Schneider,Daniel S Rampon,Ludger A Wessjohann

doi:10.5151/chempro-15bmos-bmos2013_2013915174110

Abstract

An efficient and convenient method was developed for the regioselective formation of 2-aryl- or 2,5-diarylselenophenes via a palladium-catalyzed direct arylation. This protocol is suitable for a wide range of aryl halides containing different functional groups. The 2-arylated substrates can undergo an additional regioselective direct arylation event furnishing symmetrical or unsymmetrical 2,5-diaryl selenophenes in good yield. Competition experiments and the role of the acid additive are in agreement with a concerted metalation deprotonation (CMD) pathway.

Highlights

The palladium-catalyzed direct arylation of severalarenes via direct C−H bond activation using aryl halides has brought significative advances on the synthetic area in recent years.[1]
To promote a cross-coupling reaction with the selenophene ring (1), a previous activation, either as a halide or as an organometallic (B, Mg, Sn and Zn) is required.[3]. This fact and our continuous interest in the synthesis of organoselenium compounds, prompted us to explore a new approach on the palladium-catalyzed direct arylation of selenophene
The suitable reaction conditions were developed with commercially available selenophene (1) and bromobenzene (2a)

Summary

Introduction

The palladium-catalyzed direct arylation of several (hetero)arenes via direct C−H bond activation using aryl halides has brought significative advances on the synthetic area in recent years.[1]. The palladium-catalyzed direct arylation of several (hetero)arenes via direct C−H bond activation using aryl halides has brought significative advances on the synthetic area in recent years.[1] Such couplings are very attractive to replace classical palladium catalyzed type couplings, once they do not require the preliminary synthesis of one or two organometallic derivatives.[2] these reactions are atom-economical and produce less waste.

Results

Conclusion