Visible light-mediated metal-free alkyl Suzuki–Miyaura coupling of alkyl halides and alkenylboronic acids/esters: a green method for the synthesis of allyl difluoride derivatives

Abstract

The Suzuki–Miyaura reaction has greatly facilitated the construction of C–C bonds and is well appreciated in medicinal chemistry, yet transition metal residues in this process are an unavoidable challenge. Herein, we report the first visible-light-driven photocatalyst-free coupling reaction of alkenylboronic acids/esters with α-bromodifluoroacylarenes, providing streamlining access to a series of Suzuki coupling products. The reactions proceed under metal-free conditions with a wide substrate scope. Mechanistic experiments and DFT calculation studies revealed that halogen bonding interactions, mainly generated in situ between α-bromodifluoroacylarenes and tertiary amines, could promote the C_sp³–Br bond homolytic cleavage from difluorobromoaryl ketones.