Reactions of bicyclo[4,1,0]heptane derivatives with phosphorus pentachloride

Abstract

Bicycloalkanes containing three-membered cycle possess the enhanced activity to electrophile reagents action due to raised angular and torsion strains. In this connection the study of reactions of phosphorus pentachloride with bicyclo[4,1,0]heptane derivatives are of significant interest. We pioneered in using as a latter the easily available norcarane, 7,7-dichloroand 2-alkoxy-7,7-dichloronorcaranes Ia–Ic. Under standard conditions [1], norcarane was found to phosphorylation with a small ring cleavage to form cyclohexylidenemethyland 1-chlorocyclohexylmethylphosphonic dichlorides. 7,7-Dichloronorcarane does not react with phosphorus pentachloride under similar conditions that is probably caused by the increased small ring stability. 2-Alkoxy-7,7-dichloronorcaranes Ia–Ic are phosphorylated on alkoxyl group to give 2-(7,7dichlorobicyclo[4,1,0]heptyl-2-oxy)ethenylphosphonic dichlorides IIa–IIc. Theoretically possible reaction pathway at the cycle is not observed that is proved by the absence of product with P–C bond when one carried out reaction with 2-methoxy-7,7-dichloronorcarane. This reaction gives rise only to 3-dichloromethylenecyclohexanone, the product of competitive reaction occurring at the three-membered cycle. The possible scheme of the formation of latter was described by us earlier [2]. DOI: 10.1134/S1070363210050336