Organoboron compounds : CCCXCIX. The matteson-pasto rearrangement in the series of 3-borabicyclo[3.3.1]nonane compounds

Bromination of 3-isopropyl-7-methyl- and 3-isopropyl-7-bromomethyl-3-borabicyclo3.3.1]nonane leads to corresponding 3-(2-bromo-2-propyl) derivatives, which, on treatment with alcohols or pyridine as well as on heating, undergo the Matteson-Pasto rearrangement to convert into 3-X-4,4,8-trimethyl- and 3-X-4,4-dimethyl-8-bromomethyl-3-borabicyclo4.3.1]decane (X = Br, OR). Interaction between triethylamine and 3-(2-bromo-2-propyl)-7-methyl-3-borabicyclo3.3.1]nonane is accompanied by dehydrobromination leading to 3-isopropenyl-7-methyl-3-borabicyclo3.3.1]nonane. Carbonylation of 3,4,4,8-tetramethyl-3-borabicyclo4.3.1]decane at 140°C is accompanied by migration of two alkyl groups from the boron to the carbon atom, and subsequent oxidation with H₂O₂ produces 1-(2-hydroxy-2-methyl-1-propyl)-3-acetonyl-5-methyl-cyclohexane. Under more forcing conditions (180-195°C), the third alkyl group also migrates to give, after oxidation, a mixture of isomeric 3,4,4,8-tetramethylbicyclo4.3.1]decan-3-ols. 3-n-Butoxy-4,4-dimethyl-8-bromomethyl-3-borabicyclo4.3.1]decane, on treatment with Lì, undergoes cyclization to afford 4,4-dimethyl-3-borahomoadamantane, carbonylation and subsequent oxidation of which gave 4,4-dimethylhomoadamantan-3-ol.