Chemodivergent Photocatalytic Synthesis of Dihydrofurans and β,γ-Unsaturated Ketones

A synthetic procedure, catalysed by Ir(ppy)(3) under visible-light irradiation, for the chemodivergent synthesis of 2,3-dihydrofurans (3) or beta,gamma-unsaturated ketones (7) starting from alpha-halo ketones (1) and alkenes (2) has been developed. The mild reaction conditions and the redox-neutral nature of the process make it particularly sustainable avoiding the use of both sacrificial reactants and stoichiometric strong oxidants. Careful experimental investigations, supported by DFT calculations, allowed to disclose in details a possible mechanistic pathway and to direct the synthesis chemodivergently either toward 3 or 7, depending not only on the nature of the substrates, but also on the choice of the experimental conditions.

Automated summary

A new synthetic method has been developed for the generation of 2,3-dihydrofurans or beta,gamma-unsaturated ketones starting from alpha-halo ketones and alkenes catalysed by Ir(ppy)(3) under visible-light irradiation. The redox-neutral nature of the process and mild reaction conditions make it sustainable by avoiding the use of sacrificial reactants and stoichiometric strong oxidants. Detailed mechanistic pathways have been disclosed through experimental investigations and DFT calculations, showing that the synthesis can be directed towards different products depending on the substrates and experimental conditions chosen.