Abstrakt

Theoretical calculation for determine the stability of two different geometrical isomers in stable phosphorus ylides derived from 5-methyl benzotriazole

Hojjat Ghasempour

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reactions between triphenylphosphine and dialkylacetylenedicarboxylates, in the presence of NH-heterocyclic compound, such as 5-methyl Benzotriazole. These stable ylides usually exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon partial double bond resulting fromconjugation of the ylidemoietywith the adjacent carbonyl group. In the recent work, stability of the Z- and the E- isomers were undertaken for the two rotamers of phosphorus ylides involving 5-methyl Benzotriazole by natural population analysis (NPA) and atoms in molecules (AIM) methods.