Radical-Triggered Three-Component Coupling Reaction of Alkenylboronates, α-Halocarbonyl Compounds, and Organolithium Reagents: The Inverse Ylid Mechanism.

An operationally simple protocol to affect a radical addition to alkenylboronates that spontaneously undergo a [1,2]-metalate shift is described. Overall, the reaction is a three-component coupling of an organolithium, alkenylboronic ester, and halide which takes place with broad scope and good to excellent yields. Experimental mechanistic investigations support the formation of a boron inverse ylid intermediate.