Certain characteristic features of phospholane and phosphorinane systems and electrophilicity of antibonding orbitals of phosphorus atom

Within the already proposed qualitative model for evaluating the influence of the structure of a molecule on the value of hyperconjugation reactions, the problem is discussed of the reasons for the increased electron-acceptor capacity of diheterophospholane and diheterophosphorinane fragments compared with that of the analogous acyclic systems, and also the dependence of the corresponding ^ph constants on the solvent and the type of the reaction series. The change in the acceptor capacity is attributed to a change in the valence angles at the phosphorus atom, and replacement of the hetero atoms in the ring bound to the phosphorus atom. A similar approach is used to explain the dimerization and oligomerization of cyclic phosphorus, silicon, and germanium compounds.Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 21, No. 2, pp. 159–165, March–April, 1985.