Transformations of Organoboranes at Elevated Temperatures

Abstract

Abstract Trialkylboranes with identical or different groups on the boron are stable to alkyl exchange at room temperature. Mixed trialkylboranes only undergo disproportionation in the presence of catalysts such as aluminum trialkyls and boron‐hydrogen compounds. At temperatures above 100 °C, organoboranes such as trialkylboranes and B‐alkylboracyclanes isomerize as a result of migration of the boron along the aliphatic hydrocarbon radical via dehydroboration‐hydroboration equilibria. Alkyl, cycloalkyl, as well as aralkyl and certain arylboranes can be converted irreversibly by pyrolysis at 200–300 °C into other organoboranes (methylboranes and boron‐heterocycles of various structures).