Hexakis -2-butyne

Formation of polymers and oligomers When perfluoro-2-butyne is heated, either alone or with halogen compounds or a metal carbonyl, hexakis(trifluoromethyl)benzene is obtained [303-306] (Figure 7.86). This is a very interesting compound that gives stable valence isomers on irradiation with ultraviolet light (see Chapter 9, Section HE,... 

We are mainly concerned here with general processes but two specific reactions are of some interest. Fragmentation occurs in the pyrolysis of CFBrs, giving perfluorobenzene (Figure 9.3) [3-5] this was probably the first synthesis of this compound, although it was not reported for some time. Trimerisation of hexafluoro-2-butyne leads to hexakis(trifluoro-methyl)benzene [6,7], areaction that was referred to in Chapter 7, Section lllB, Subsection 1. 

Hexafluoro-2-butyne undergoes 1,4 addition by reaction with Rh(dik)(diolefin) (dik = acac, dpm, dbm diolefin = cod, norbornadiene), with formation of a C—C bond between the alkyne and the methyne carbon atom of the /3-diketonate. Additional trimer-ization of hexafluoro-2-butyne to hexakis(trifluoromethyl)benzene and /j -arene coordination of the latter to rhodium affords 103 (equation 73). 

Reaction of red phosphorus with hexafluoro-2-butyne in the presence of a catalytic amount of iodine at 200° for 8 hr. results in the direct formation of 2,3,o,6,7,8-hexakis-(trifluoromcthy))-l, 4-dipho.sphabicyclo-[2.2.2. jocta-2,5,7-triene in 43% yield (21). The same product was... 

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