Brønsted Acid-Promoted Intermolecular Dearomative Photocycloaddition of Bicyclic Azaarenes with Olefins under Aerobic Conditions
Manotosh Bhakat, Bitasik Khatua, Promita Biswas, Joyram Guin
Abstract
Herein, we present a simplified reaction protocol for the dearomatization of bicyclic azaarenes via photochemical cycloaddition with alkenes using an Ir(III) photosensitizer, trifluoroacetic acid (TFA), dichloroethane, and a blue light-emitting diode. An efficient protonation of azaarenes with TFA enhances the reactivity of triplet azaarene toward olefins, enabling the photocycloaddition under aerobic conditions. The protocol applies to a broad range of substrates. Control experiments indicate a strong correlation between the degree of protonation of azaarene and the product yield.
Topics & Concepts
ChemistryBicyclic moleculeProtonationTrifluoroacetic acidCycloadditionPhotosensitizerYield (engineering)Intermolecular forceBrønsted–Lowry acid–base theoryPhotochemistryMedicinal chemistryOrganic chemistryCatalysisMoleculeMetallurgyMaterials scienceIonRadical Photochemical ReactionsCatalytic C–H Functionalization MethodsSulfur-Based Synthesis Techniques