Free radical addition to olefins. Part 19.—Trifluoromethyl radical addition to fluoro-substituted propenes and its absolute rate of addition to ethylene

Abstract

The rates of addition of trifluoromethyl radicals to each end of propene, l,l,l-trifluoropropene and hexafluoropropene have been determined using a competitive technique, taking as a standard the rate of addition to ethylene. The rate of addition of trifluoromethyl radicals to ethylene (2) has been compared with the rate of combination of trifluoromethyl radicals (6), and a value of kz/ki = (1.6 & 0.2) x lo3 exp (-2 900 f 500 cal mol-'/RT) dm3 mol-3 s* was determined (1 cal = J).CFs*+ CH2=CHz -+ CF3CHZCH2.(2) CFj*+ CF3* -+ C2Fe.kz ks Since the value of ks is now well established, a new value of the absolute rate of addition of trifluoromethyl radicals to ethylene and to the other olefins can be computed. EXPERIMENTAL Materials were obtained and purified as described previously,1o and were handled on a conventional mercury-free vacuum line. Reactions with ethylene, propene, 1,l ,I-trifluoropropene and hexafluoropropene were carried out in cylindrical Pyrex cells (1 85 and 237 cm3).

Synergistic photoredox and copper catalysis by diode-like coordination polymer with twisted and polar copper–dye conjugation

“…Structurally complex small molecules containing repeating functional groups 47 , like multiple olefinic natural products, have an extraordinary capacity for a wide range of useful functions 48 . The similar thermodynamic reactivities of different olefinic sites of natural derivatives made the discrimination of olefinic groups a challenging task in the presence of highly active CF 3 radicals, like in the case of trifluoromethylation-chloration difunctionalisation (Supplementary Table 6 ) 49 . Here, the natural flavour derivative 7l containing a carbonyl-adjacent olefin and a carbonyl-free olefin in the molecular scaffold was chosen as the model substrate 50 .…”

Random and sequential radical cotelomerizations of 3,3,3‐trifluoropropene (H2CCHCF3) with vinylidene fluoride (F2CCH2)

“…4,5 In the mid 70ies, Low et al 6 also investigated this reaction under UV radiation, and obtained a mixture of both normal and reverse monoadducts. In the 80ies, Russian teams studied the telomerization of TFP with non-fluorinated telogens such as alcohols, esters, tetrachloromethane, tribromomethane, benzyl chloride, under redox complexes (e.g.…”

Synergistic photoredox and copper catalysis by diode-like coordination polymer with twisted and polar copper-dye conjugation

“…48 The similar thermodynamic reactivities of different ole nic sites of natural derivatives made the discrimination of ole nic groups a challenging task in the presence of highly active CF 3 radicals, like in the case of tri uoromethylation-chloration difunctionalisation (Table S6). 49 Here, the natural avour derivative 7 l containing a carbonyl-adjacent ole n and a carbonyl-free ole n in the molecular scaffold was chosen as the model substrate. 50 DFT calculation revealed the thermodynamic feasibility of docking the carbonyl site of substrate 7 l through Cu-O interaction (Table S7), with a free energy change of ca.…”