Synthesis and Properties of Azoles and Their Derivatives. 54. The Regioselectivity of [2+3] Cycloaddition Of C,C,N-Triphenyl- and Z-C,N-Diphenylnitrones With β- and α-Substituted Nitroethylenes in Light of Frontier Molecular Orbital Theory

Using quantum-chemical calculations we have carried out an analysis of frontier molecular orbital interactions in the [2+3] cycloaddition reactions of C,C,N-triphenyl- and Z-C,N-diphenylnitrones with β- and α-substituted nitroethylenes. In all of the examples studied the orbital effects lead to the formation of the corresponding 4-nitroisoxazolidines.