Ni-Catalyzed Carboxylation of C(sp<sup>2</sup>)–S Bonds with CO<sub>2</sub>: Evidence for the Multifaceted Role of Zn
作者:Tomoyuki Yanagi、Rosie J. Somerville、Keisuke Nogi、Ruben Martin、Hideki Yorimitsu
DOI:10.1021/acscatal.9b05141
日期:2020.2.7
Nickel-catalyzed reductive carboxylation reactions of aryl electrophiles typically require the use of metallic reducing agents. At present, the prevailing perception is that these serve as both a source of electrons and as a source of Lewis acids that may aid CO2 insertion into the Ni–C bond. Herein, we provide evidence for the in situ formation of organometallic species from the metallic reductant
芳基亲电子试剂的镍催化的还原羧化反应通常需要使用金属还原剂。目前,普遍的看法是它们既可以作为电子来源,又可以作为路易斯酸的来源,可以帮助CO 2插入Ni-C键。本文中,我们提供了从金属还原剂原位形成有机金属物种的证据,该步骤在与金属粉末还原剂的催化羧化反应中已经被排除或未被探索。具体来说,我们证明Zn(0)充当还原剂,并且Zn(II)生成可能在芳基ulf盐的C(sp 2)-S羧化反应中起作用的芳基锌物质。总体而言,还原性镍催化的C(sp 2)–S羧化反应在温和的条件下在非酰胺溶剂中进行,显示出较宽的底物范围,可用于芳烃的正式对位C–H羧化反应。