Visible light-induced iridium(iii)-sensitized [2 + 2] and [3 + 2] photocycloadditions of 2-cyanochromone with alkenes??

Organic & Biomolecular Chemistry Pub Date: 2023-07-11 DOI: 10.1039/D3OB00862B

Abstract

2-Cyanochromone (1) readily undergoes visible light-induced photocycloadditions with diverse alkene partners mediated by (Ir[dF(CF3)ppy]2(dtbpy))PF6 as the photosensitizer. While mono-, di- and trisubstituted styrenes and acrylonitriles as the reactants lead to [2 + 2] cycloadducts with good regiocontrol and high diastereoselectivity, the use of trialkyl-substituted alkenes allows for the isolation of cyclopentenone-fused chromones resulting from a [3 + 2] cycloaddition process in moderate yields.

Graphical abstract: Visible light-induced iridium(iii)-sensitized [2 + 2] and [3 + 2] photocycloadditions of 2-cyanochromone with alkenes
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