Free-radical-mediated carbonylative cyclisation of alk-4-enyl halides leading to cyclopentanones

Abstract

Alk-4-enyl bromides and iodides 1, when treated with the tributyltin hydride/CO system, undergo carbonylative cyclisation to give Cyclopentanones in good yields (AIBN cat., benzene, 75–90 atm, [1]= 0.025–0.05 mol dm–3, 80 °C, 2–3 h).