Photocatalyzed C–F Bond Heteroarylation of Trifluoromethyl­arenes with Heteroarenes: Two Roles of Bu₃SnI as Fluoride Ion Scavenger and Activator for Photocatalyst

Abstract

We report the C–F bond heteroarylation of trifluoromethylarenes with heteroarenes by using Ir(ppy)₃ catalyst and Bu₃SnI under visible-light irradiation. Various heteroarenes such as pyrrole, furan, and thiophene derivatives were applied to the present reaction. The present heteroarylation enables the transformation of various functionalized trifluoromethylarenes because of the mild reaction conditions. Notably, the late-stage transformation of a drug molecule, bicalutamide, was demonstrated. Mechanistic studies including a light on–off interval experiment, Stern–Volmer luminescence-quenching measurements, and DFT calculations clarified two critical roles of Bu₃SnI for the successful progress of the heteroarylation. Bu₃SnI functions as a fluoride ion scavenger to suppress the undesired C–F bond re-formation. Bu₃SnI also acts as a single-electron source for the reduction of photoexcited Ir(ppy)₃* to generate Ir(II) species to effectively reduce ArCF₃.

Key words

C–F bond transformation - diaryldifluoromethanes - heteroarylation - photocatalysis - organostannanes - pyrroles - furans - thiophenes

Publication History

Received: 28 November 2023

Accepted after revision: 22 December 2023

Accepted Manuscript online:
22 December 2023

Article published online:
29 January 2024

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