The reaction of methyllithium with trimethoxyborane at-78 “C in ethyl ether yields a mixture of methylated boranes and their corresponding “ate” complexes. We have found that under the same conditions triisopropoxyborane reacts cleanly with methyllithium to form the lithium methyltriisopropoxyborate complex. Protonation of this complex with anhydrous hydrogen chloride quantitatively yields methyl diisopropoxyborane. This reaction of organolithium ...
