An environmentally benign and high-rate Appel type reaction

Abstract

A high rate, selective, and productive Appel type reaction was developed. The method allows for ipso-substitution of the alcoholic hydroxy group with halogens ∈ [Cl, Br, I]. The method demands mild reaction conditions that include a very short reaction time, <15 min only, versus reaction times of several hours or days using the classical Appel reaction conditions (PPh₃ + CCl₄ + R–OH). The method was demonstrated to operate with the cheap and easily available 1,3-dihalo-5,5-dimethylhydantoins and N-halo succinimides (halo ∈ [Cl, Br, I]) as the reagent that performs the halogenation of PPh₃. The reaction protocol operated with several acceptable solvents rather than DCM that was used in the classical Appel reaction. Furthermore, the batch protocol was also translated and successfully implemented on a flow reactor platform (t < 5 min, y = 95%).