Methylation of Alcohols with Diazomethane

Methylation of alcohols by the Williamson synthesis requires strongly basic conditions and there is no satisfactory general methylation procedure effective under neutral or mildly acidic conditions. In principle, diazomethane with an acidic catalyst should methylate alcohols, but the usual protonic acid, such as hydrochloric acid, is unsatisfactory because it is itself methylated with diazomethane. Fluoroboric acid, however, promised to serve as a useful catalyst since it would be consumed in reaction with diazoinethane only by some process involving rupture of a B-F bond. This expectation was indeed realized and a novel method has been developed for methylation of alcohols in high yields under mild conditions