The methoxymethyl ether (MOM) group is a well-known acid-labile protecting group for alcohols and phenols due to its ease of installation and high stability in strongly basic condition. A number of methods are available for removal of the MOM group and while each of these cleavage conditions has its own attributes, synthetic applications of these methods have been hampered due to the high reactivity, use of expensive stoichiometric reagents and tedious work-up procedures. We recently reported a mild method for removal of phenolic MOM ethers using 30 mol% of bismuth trichloride in acetonitrile/water at 50oC. We have now extended this mild protocol to MOM esters of carboxylic acids, primary, secondary, tertiary and alkenyl alcohol substrates. The deprotection of the MOM groups proceeded in good to excellent yields. Notable features of the cleavage protocol entail use of a “green” bismuth reagent, ease of handling, low cost, operationally simple and good functional group compatibility. While a number of organic reactions involving bismuth (III) compounds have been reported, little is known about the exact nature of the reactive bismuth species and hence, the mechanisms of these reactions are still poorly understood. We are currently investigating the mechanistic pathway of the bismuth trichloride mediated MOM cleavage reaction using ab initio methods and preliminary results will be discussed.

General mild method for cleavage of methoxymethyl ethers using bismuth trichoride

255th National Meeting (2018)

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