Continuous Synthesis of Organozinc Halides Coupled to Negishi Reactions

Abstract

The Negishi cross‐coupling is a powerful CC bond forming reaction. The method is less commonly used relative to other cross‐coupling methods in part due to lack of availability of organozinc species. While organozinc species can be prepared, problems with reproducibility and handling of these sensitive species can complicate these reactions. Herein, we describe the continuous formation, using an activated packed‐bed of metallic zinc, and subsequent use of organozinc halides. We demonstrate that a single column of zinc can provide excellent yields of organozinc halides and that they can be used downstream in subsequent Negishi cross‐couplings. The preparation of the zinc column and the scope of the reaction are discussed.magnified image