Mild Deprotection of Methylene Acetals in Combination with Trimethylsilyl Triflate-2,2′-Bipyridyl

The facile deprotection of methylene acetal protection of diols tinder mild conditions is established. The combination of trimethylsilyl triflate (TMSOTf) and 2,2'-bipyridyl followed by a weakly acidic hydrolysis is-as effective and the substrates having acid sensitive functional groups can be tolerated under the stated conditions. The selective deprotection between methylene acetal and benzophenone ketal was achieved.