Bifunctional Ligand Enables Gold-Catalyzed Propargyl C-H Functionalization via Reactive Gold Allenylidene Intermediate

Angew Chem Int Ed Engl. 2024 Apr 25:e202402286. doi: 10.1002/anie.202402286. Online ahead of print.ABSTRACTGold allenylidene species have been seldom exploited as reactive intermediates in synthetically versatile catalytic reactions. By employing alkynylbenziodoxoles as the substrates and bifunctional WangPhos as the metal ligand, this work demonstrated ready catalytic access to these intermediates of general substitution patterns and their electrophilic reactivities at the γ-carbon center with a diverse range of nucleophiles. The reaction is driven by the reductive decomposition of the benziodoxole moiety and achieves the replacement of a propargylic proton with a N/O/C-based nucleophile, hence realizing reactivity umpolung. Corroborated by DFT calculations, the reaction mechanism involves a mild propargylic deprotonation. In contrast to prior works employing a tertiary amine functionality, A barely BrØnsted-basic amide group in WangPhos is surprisingly effective in deprotonation at the propargylic position under a gold-ligand cooperation regime.PMID:38659404 | DOI:10.1002/anie.202402286

Source: Angewandte Chemie - April 25, 2024 Category: Chemistry Authors: Yongliang Wei Jingxing Jiang Yaru Jing Zhuofeng Ke Liming Zhang Source Type: research