Unusual and Unexpected Reactivity of t-Butyl Dicarbonate (Boc2O) with Alcohols in the Presence of Magnesium Perchlorate. A New and General Route to t-Butyl Ethers

In the past few years, metal perchlorates have been widely exploited as Lewis acid promoters in various organic transformations. A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4)2 and Boc2O and shows general applicability. The procedure provides a very good method for obtaining t-butyl ethers from alcohols, since it works under mildly acidic conditions and many functional groups survive the protection process. Moreover, all side products of the reaction are volatile compounds, so that the purification of the products is very simple and convenient. Typically, t-butyl ethers have to be separated only from the residual starting materials. Finally, a simple and mild method for deprotecting t-butyl ethers based on the CeCl3.7H2O/NaI system gives very satisfactory preliminary results.