COMPARISON OF THE NUCLEOPHILICITIES OF ALKYNES AND ALKENES - QUANTITATIVE-DETERMINATION OF THE NUCLEOPHILICITIES OF ALKYNES TOWARD CARBENIUM IONS

Relative reactivities of alkenes and alkynes toward diarylmethyl catio ns have been determined by direct rate measurements and by competition experiments in dichloromethane. At -70 degrees C alkynes are found to be one to two orders of magnitude less reactive than analogously subs tituted alkenes (e.g. phenylacetylene/styrene), but the reactivity dif ference reduces strongly as the temperature is raised. The stereochemi stry of the vinyl chlorides produced by addition of benzhydryl chlorid es to alkynes is characterized.