Nickel-Catalyzed Carbonylative Coupling of Alkylzinc Reagents and α-Bromo-α,α-difluoroacetamides

Abstract

Herein, we report a nickel catalyzed carbonylative cross coupling of alkyl zinc reagents and α,α-difluorobromoaceamides to obtain α,α,-difluoro-α-ketoamides in moderate to good yields. The reaction is catalyzed by a bench stable nickel(II) pincer complex, in contrast to other reports based on palladium catalysts. The carbonylative reaction is performed in a two-chamber system (COware®), in which carbon monoxide (CO) is generated ex situ from the solid precursor, SilaCOgen, and consumed in the adjacent chamber. The reaction operates at low temperatures using near stoichiometric amounts of CO, and isotopically labeled products are effortlessly accessed as demonstrated using 13C-labeled SilaCOgen.

Cluster Preface: Special Issue Honoring Masahiro Murakami’s Contributions to Science

“…22 Nakao describes a new protocol for the catalytic denitrative generation of openshell species from simple nitroalkanes by using 9-fluorenol as a single-electron-transfer catalyst. 23 Following up their interest in carbon-labelling, Neumann and Skrydstrup describe a Ni-catalyzed carbonylative coupling of alkyl zincs with ,-difluorobromoacetamides by using near-stoichiometric CO. 24 A contribution from Rovis shows the potential of electronically controlled Ru-catalyzed olefin metathesis with only electricity as a stimulus. 25 While decarboxylation techniques are certainly rare, Shigeno and Kondo provide an interesting endeavor that meets such a challenge, allowing access to dicarboxylated structures by harnessing the potential of combined Brønsted bases.…”

“…22 Nakao describes a new protocol for the catalytic denitrative generation of open-shell species from simple nitroalkanes by using 9-fluorenol as a single-electron-transfer catalyst. 23 Following up their interest in carbon-labelling, Neumann and Skrydstrup describe a Ni-catalyzed carbonylative coupling of alkyl zincs with α,α-difluorobromoacetamides by using near-stoichiometric CO. 24…”