Origin of Thermodynamic versus Kinetic Control of Allene Hydroboration with 9-Borabicyclo[3.3.1]nonane and 10(R)-Trimethylsilyl-9-Borabicyclo[3.3.2]decane

Density functional theory was used to locate transition states for hydroboration reactions of allenes with 9-borabicyclo[3.3.1]nonane and 10-R-9-borabicyclo[3.3.2]decane, as well as transition states for [1,3]-boratropic shift and aldehyde addition reactions of the derived allylboranes. The origin of kinetic versus thermodynamic control in the allene hydroboratlon step Is described.