Telomerization of 3,3,3-Trifluoroprop-1-ene and Functionalization of Its Telomers

Abstract

The synthesis of four 3,3,3-trifluoroprop-1-ene telomers (RF(C3H3F3)nI, n = 1, 2, RF = n-C6F13- or (CF3)2CF-) and their allyl derivatives RF(C3H3F3)nCH2CH=CH2 are presented. The allyl telomers were prepared by a three-step reaction. The first step involved the thermal and peroxide-induced bulk telomerization of 3,3,3-trifluoroprop-1-ene (TFP) with heptafluoro-2-iodopropane or tridecafluoro-6-iodohexane leading to monoadduct and diadduct, the ratio of which depends on the R0 = [RFI]0/[TFP]0 initial molar ratio and the reaction temperature. The amount of monoadduct increased up to 50-60% and of the diadduct to 25-30% at temperatures up to 180 °C (thermal-initiated) and 150 °C (initiated with di-tert-butyl peroxide, DTBP), R0 up to 1.5. It was observed that the addition of the (CF3)2CF• radical onto the =CH2 of TFP was regioselective leading to selective formation of a single isomer in contrast to the addition of the n-C6F13• radical. Then, the telomers reacted with allyl acetate yielding RF(C3H3F3)nCH2CH(I)CH2OCOCH3 (n = 1, 2) in 50-80% yields. The third step consisted of a deiododeacetatization of these iodoacetates into RF(C3H3F3)nCH2-CH=CH2 (C,n) giving 50-80% yields. All the intermediates were characterized by 1H, 19F and products by 13C NMR spectroscopy.