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Gold N‐Heterocyclic Carbene Catalysts for the Hydrofluorination of Alkynes Using Hydrofluoric Acid: Reaction Scope, Mechanistic Studies and the Tracking of Elusive Intermediates
Author(s) -
Gauthier Raphaël,
Tzouras Nikolaos V.,
Zhang Ziyun,
Bédard Sandrine,
Saab Marina,
Falivene Laura,
Van Hecke Kristof,
Cavallo Luigi,
Nolan Steven P.,
Paquin JeanFrançois
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202103886
Subject(s) - chemoselectivity , carbene , catalysis , chemistry , phosphine , combinatorial chemistry , reactivity (psychology) , trifluoromethanesulfonate , counterion , substrate (aquarium) , organic chemistry , medicine , ion , oceanography , alternative medicine , pathology , geology
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.