Thexylborane is a borane with the formula [Me<sub>2</sub>CHCMe<sub>2</sub>BH<sub>2</sub>]<sub>2</sub> (Me = methyl). The name derives from "t-hexylborane" (although the group is not the standard tert-hexyl group), and the formula is often abbreviated ThxBH<sub>2</sub>. A colorless liquid, it is a monoalkylborane. It is produced by the hydroboration of tetramethylethylene:
Thexylborane is generated in situ. In solution, it isomerizes over the course several days to the 2,3-dimethyl-1-butyl derivative, shown as the monomer here:
Thexylborane allows the synthesis of ketones by coupling a pair of alkenes with carbon monoxide, which serves as a carbonyl linchpin:
An important feature of this reagent is that the thexyl group almost never undergoes anionotropic 1,2-migration from boron to a neighboring atom.