Thexylborane

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 rare, easily accessed monoalkylborane. It is produced by the hydroboration of tetramethylethylene:
 * B2H6 +  2 Me2C=CMe2  →  [Me2CHCMe2BH2]2

Reactions
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:
 * Me2CHCMe2BH2 →  Me2CHCH(Me)CH2BH2

Thexylborane allows the synthesis of ketones by coupling a pair of alkenes with carbon monoxide, which serves as a carbonyl linchpin:
 * Me2CHCMe2BH2 +  2 RCH=CH2  →  Me2CHCH(Me)CH2B(CH2CH2R)2
 * Me2CHCH(Me)CH2B(CH2CH2R)2 +  CO  +  H2O  →   O=C(CH2CH2R)2  +  ...

An important feature of this reagent is that the thexyl group almost never undergoes anionotropic 1,2-migration from boron to a neighboring atom.