External Photocatalyst-Free Visible Light-Promoted 1,3-Addition of Perfluoroalkyl Iodides to Vinyldiazoacetates

Abstract

Alkenes and alkynes are typical substrates used in atom transfer radical addition (ATRA) reactions, resulting in the formation of vicinal disubstituted products. In this report, vinyldiazoacetates were first developed as the radical acceptors in an ATRA reaction of RfI, leading to 1,3-difunctional adducts. The reaction is driven by visible light, without the need for external photocatalysts and additives. A series of control experiments and density functional theory (DFT) calculations indicate the 1,3-addition proceeds via a radical-chain process and the initial Rf radical was generated by homolytic dissociation of a radical pair complex of triplet free vinylcarbene and perfluoroalkyl iodide. After postreaction isomerization, various 1-iodo-3-perfluoroalkyl-alkenes were obtained in good yields with high Z selectivity. The synthetic utility of the ATRA 1,3-adduct was demonstrated by cross-coupling reactions and defluorination of perfluoroalkyl groups.