Structure and bonding nature of the strained Lewis acid 3-methyl-1-boraadamantane: a case study employing a new data-analysis procedure in gas electron diffraction.

Base-free 3-methyl-1-boraadamantane was synthesized by starting from its known THF adduct, transforming it to a butylate-complex with n-butyllithium, cleaving the cage with acetyl chloride to give 3-n-butyl-5-methyl-7-methylene-3-borabicyclo[3.3.1]nonane and closing the cage again by reacting the latter with dicyclohexylborane.