1: 2,2'-bis-(diphenylphosphino)-1,1'- binaphthyl; copper(l) chloride / methanol / 1 h / Reflux; Inert atmosphere 2: toluene-4-sulfonic acid / toluene / 60 h / Molecular sieve; Reflux; Inert atmosphere; Dean-Stark trap 3: 3-chloro-benzenecarboperoxoic acid / dichloromethane / 0.5 h / -78 °C / Inert atmosphere View Scheme