Organophosphorus chemistry. Part XI. Reactions of dimethyl- and bis(trifluoromethyl)-phosphine with olefins, and photochemical reaction of ethyl(bistrifluoromethyl)phosphine with ethylene

Abstract

Dimethylphosphine gives two-way addition with vinyl fluoride under u.v. irradiation forming the 1-fluoroethyl- and 2-fluoroethyl-dimethylphosphines in high yield in the ratio 8:92. With 1,1-difluoroethylene it gives a high yield of 1,1-difluoroethyl- and 2,2-difluoroethyl-dimethylphosphines in the ratio 28 : 72, but with propene only dimethyl-n-propylphosphine is produced. Bis(trifluoromethyl) phosphine gives only one adduct with each olefin. In all cases the product, or the major product where two are formed, is that predicted on the basis of formation of the most stable intermediate radical. Neither bis(trifluoromethyl)phosphine nor phosphine react with 1,1,3,3,3-pentafluoropropene under u.v. irradiation. Dimethylphosphine reacts as a nucleophile with this olefin during irradiation or in the dark to give a mixture of cis- and trans-1-dimethylphosphino-1,3,3,3-tetrafluoropropene. Irradiation of ethylbis(trifluoromethyl)phosphine and ethylene gives ethyltrifluoromethyl-3,3,3-trifluoropropylphosphine, the first example of photochemical addition of a trialkylphosphine to an olefin.