Novel Perfluoroalkyl-Diphenylphosphine Compounds. Syntheses and Reaction Mechanisms

SANTIAGO E. VAILLARD, AL POSTIGO, Y ROBERTO A. ROSSI

ORGANOMETALLICS

AMER CHEMICAL SOC

Año: 2004 vol. 23 p. 3003 - 3007

0276-7333

A new class of perfluoroalkyl compounds, containing novel Rf-Ph2P bonds (where Rf is the perfluoroalkyl moiety), were synthesized in fairly good yields, and their reaction mechanisms were studied in different solvents. Thus, the reaction of 1-iodo-n-perfluorohexane (1a) in liquid ammonia afforded only the hydro deiodination product (3a), and underirradiation a low yield of diphenyltridecafluorohexylphosphine (2a) was obtained. However,good yields (72%) of substitution products were obtained with 1a and 1-iodo-n-perfluorobutane (1c) under irradiation in HMPA and DMPU as solvents. These reactions were  completely inhibited with di-tert-butyl nitroxide, a good free radical scavenger. Thephotostimulated reaction of 1,4-diiodoperfluorobutane (1d) in HMPA afforded the disubstitution product in 55% isolated yield. Low yields of substitution products were obtained with1a and 1c either in the dark or under irradiation in tetraglyme. It is suggested that the reactions in HMPA and DMPU occur by the SRN1 mechanism, whereas halogen metalexchange is the main reaction in liquid ammonia and tetraglyme.