Theoretical study of rapid topomerization in tetracyclo[4.4.4.4]-1-bora-3,5-diazapentane

The rearrangement of a novel (hypothetical) stereochemical nonrigid system, tetracyclo[4.4.4.4]-1-bora-3,5-diazapentane, of the pendulum type has been studied by ab initio (RHF/6-31G∗∗, RHF/DZP, BLYP/DZP and MP2/6-31G∗∗) calculations. The calculations show that the system undergoes rapid topomerization with a low-energy barrier of about 6.7–11.8 kcal/mol and probably possesses sufficient thermodynamic stability to be a feasible synthetic target.