1.1: sodium dihydrogenphosphate; 3-chloro-benzenecarboperoxoic acid / dichloromethane / 10 h / 0 °C / Inert atmosphere 2.1: dipyridinium dichromate / dichloromethane / 2 h / 20 °C / Inert atmosphere; Molecular sieve 3.1: Mes3B; sodium / tetrahydrofuran / 3 h / -78 °C / Inert atmosphere 3.2: -78 - 20 °C / Inert atmosphere 4.1: toluene-4-sulfonic acid / toluene / 2 h / Inert atmosphere; Reflux View Scheme