F-2,4-Dimethyl-3-ethyl-3-pentyl and F-2,4-dimethyl-3-isopropyl-3-pentyl; stable tert-perfluoroalkyl radicals prepared by addition of fluorine or trifluoromethyl to a perfluoroalkene

Abstract

Aus der Fluorierung von (I) geht das gegenüber Dimerisierung, O2, C12, Brz, I2 beständige, perfluorierte Alkylradikal (II) hervor, das jedoch mit F2 bei Zimmertemp.

Synthesis and Conformational Studies of Methylated, Highly Branched Fluoroolefins: Gear‐Meshed Conformational Isomers

“…CH 3 Li, on the other hand, was more reactive towards monomethylated fluoroolefins 1 and 2, giving dimethylated fluoroolefins [(Z)-3, 4] with the use even of 1.2 mol-equiv. CH 3 Li for T-3. The product distributions and yields obtained from treatment of T-3 with various amounts of CH 3 Li (1.2Ϫ6.0 mol-equiv.…”

“…against T-3) are shown in Table 1. An increase in the amount of CH 3 Li used with T-3 from 1.2 to 2.5 mol-equiv. caused a dramatic decrease in the yields of the monomethylated products (Z)-1 (from 30 to 4.6%) and 2 (from 12 to 1.9%), and a significant increase of the dimethylated, products (Z)-3 (from 6.3 to 31%) and 4 (from 2.9 to 14%) instead (Entry 2).…”

“…The cyclized product 5 and the reduced product 6 were reported previously, [22] and the other diene 11, newly found this time, is discussed later. Although the (CF 3 ) 2 Cϭ group of T-3 is bulkier than the (CF 3 )CFϭ group of T-2, their reactivities towards CH 3 Li or CH 3 MgBr were almost the same. In contrast, nucleophilic attacks on trimers T-2 and T-3 occurred only at the C-2 site and not at the C-3 site with bulkier substituents such as C 2 F 5 or (CF 3 ) 2 CF groups.…”

“…[2] The unique properties of fluoroolefins mainly derive from the electronegativity and/or the steric hindrance of fluorinated substituents. As an example, persistent perfluoroalkyl radicals, which can be prepared either by direct fluorination or by electrochemical fluorination of highly branched fluoroolefins, [3,4] are stable to oxidizing agents, acids, and bases, and in one particular case even to 100% fluorine gas. Such surprising properties and reactivities are due to the presence of highly branched perfluoroalkyl groups surrounding the radical center.…”

Radical copolymerisation of chlorotrifluoroethylene with isobutyl vinyl ether initiated by the persistent perfluoro-3-ethyl-2,4-dimethyl-3-pentyl radical

“…The synthesis of fluorinated copolymers specially designed to overcome the problematic properties of the homopolymers has been the focus of extensive research. 4,8,9 Recently Patil et al 10 utilised the persistent perfluoro-3-ethyl-2,4-dimethyl-3-pentyl radical (abbreviated as PPFR 11 , structure shown in Figure 1) to generate •CF 3 radicals for polymerisation initiation. The resulting CF 3 end groups were used in 19 F NMR spectroscopy for the determination of average molecular weights of VDF copolymers.…”