Thexylborane is a borane with the formula [Me2CHCMe2BH2]2 (Me = methyl).

The name derives from "t-hexylborane" (although the group is not the standard tert-hexyl group), and the formula is often abbreviated ThxBH2.

A colorless liquid, it is a monoalkylborane.

It is produced by the hydroboration of tetramethylethylene:[1] 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:[1] An important feature of this reagent is that the thexyl group almost never undergoes anionotropic 1,2-migration from boron to a neighboring atom.