PROTEO, CCVC, Département de chimie, Université Laval, 1045 avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
Department of Chemistry and Centre for Sustainable Chemistry, Ghent University, Krijgslaan 281, S-3, 9000, Ghent, Belgium.
Chemistry. 2022 Jan 19;28(4):e202103886. doi: 10.1002/chem.202103886. Epub 2021 Nov 24.
An efficient and chemoselective methodology deploying gold-N-heterocyclic carbene (NHC) complexes as catalysts in the hydrofluorination of terminal alkynes using aqueous HF has been developed. Mechanistic studies shed light on an in situ generated catalyst, formed by the reaction of Brønsted basic gold pre-catalysts with HF in water, which exhibits the highest reactivity and chemoselectivity. The catalytic system has a wide alkyl substituted-substrate scope, and stoichiometric as well as catalytic reactions with tailor-designed gold pre-catalysts enable the identification of various gold species involved along the catalytic cycle. Computational studies aid in understanding the chemoselectivity observed through examination of key mechanistic steps for phosphine- and NHC-coordinated gold species bearing the triflate counterion and the elusive key complex bearing a bifluoride counterion.
一种高效且具有化学选择性的方法，利用金-氮杂环卡宾（NHC）配合物作为催化剂，在水相 HF 中实现末端炔烃的氢氟化反应，已经被开发出来。机理研究揭示了一种原位生成的催化剂，它是由 Brønsted 碱性金前催化剂与水相中的 HF 反应形成的，该催化剂表现出最高的反应活性和化学选择性。该催化体系具有广泛的烷基取代底物范围，并且使用设计好的金前催化剂进行的计量和催化反应能够鉴定出催化循环中涉及的各种金物种。计算研究通过考察带有三氟甲磺酸根阴离子的膦和 NHC 配位的金物种以及难以捉摸的带有双氟化物阴离子的关键配合物的关键机理步骤，有助于理解观察到的化学选择性。
