Formation of 3-Alkynylidenephthalides by Gold(I)-Catalyzed Alkynylative Cyclization of o-Alkynylbenzoic Acids under
María Ballarín-Marión1, Jorge C Herrera-Luna1, Vincent Corcé1
1Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, 4 place Jussieu, 75005 Paris, France.
Abstract:
Herein, we report a Csp2-Csp cross-coupling process involving the merger of gold catalysis and visible light photocatalysis leading to the alkynylative cyclization of o-alkynyl benzoic acids. The corresponding and previously undescribed alkynylidenephthalide products were obtained as mixtures of E:Z isomers. The key C-C bond formation is based on the photoactivation of the oxidative addition of an alkynyliodide to a vinylgold(I) intermediate resulting from an initial 5-exo-dig cyclization pathway, as supported by mechanistic studies including DFT calculations.
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