Methylation of Alcohols (Diazomethane Method)

An alcohol reacted with diazomethane (CH2N2) in the presence of a catalyst such as fluoroboric acid (HBF4) gives the corresponding methyl ether, releasing nitrogen gas: CH3-CH2-OH + CH2N2 (HBF4, heat) gives CH3-CH2-O-CH3 + N2. This method is a mild, high-yielding way to methylate a sensitive alcohol without the acidic conditions of dehydration, and it is the ONLY route among the three ether-preparation methods here that can methylate an alcohol without also risking elimination or carbo …