Perfluoro-1,3-diene complex

Curiously, no ij4-diene complexes have been obtained using perfluoro-cyclopentadiene, although a number of rj2 complexes such as 38 (32), 39 (83a), and [Co(f/5-C5H5)(CO)(f/2-C5F6)] (Si) have been prepared. Once again, the propensity for formal oxidative addition is revealed by the formation of complex 31 (see Section II1,D) in the reaction of perfluorocyclopentadiene with... 

A more efficient agent than peroxy compounds for the epoxidation of fluoro-olefins with nonfluonnated double bond is the hypofluorous acid-acetomtrile complex [22] Perfluoroalkylethenes react with this agent at room temperature within 2-3 h with moderate yields (equation 13), whereas olefins with strongly electron-deficient double bond or electron-poor, sterically hindered olefins, for example l,2-bis(perfluorobutyl)ethene and perfluoro-(l-alkylethyl)ethenes, are practically inert [22] Epoxidation of a mixture of 3 perfluoroalkyl-1-propenes at 0 C IS finished after 10 mm in 80% yield [22] The trifluorovinyl group in partially fluorinated dienes is not affected by this agent [22] (equation 13)... 

In contrast to its reported reaction with perfluorocyclopentadiene to give 31 (see Section III,D), [Co2(CO)8] has been shown to react with perfluoro-cyclohexa-1,3-diene to yield the dinuclear /i-alkyne complex 45 (111,112). The... 

The hetero-Diels-Alder (HDA) reaction of 2,3-dimethylbuta-1,3-diene and cyclohexa-1,3-diene with ethyl glyoxylate catalysed by chiral Zn(II) complexes yields both the dihydropyran and the ene product, the former predominating. The enantiomeric excess, which can reach 87%, is dependent on the solvent as well as the catalyst <97JCS(P1)2345>. Use of (Rs,E)-3-[(15)-isoborneol-10-sulfinyl]-l-methoxybutadiene gives the 5,6-dihydropyran with good endo and facial diastereoselectivity <97TA2989>. Scandium(III) perfluoro-octanesulfonate is an efficient catalyst in the HDA reaction of aldehydes with non-activated dienes <97BCJ1421>. 

The availability of perfluoro-3-methylbuta-l -diene on a reasonable scale led to a reinvestigation of its thermal dimerization, previously supposed to be accompanied by extensive polymerization. The main component of the dimer fraction (which is a complex mixture of several isomers) has now been firmly identified as the unsymmetrically disposed, centre-centre-linked dimer (148), but the supposed polymeric solid is in fact the hydrolysis product (149), which coincidentally has the same carbon content as a polymer CsnFsn- No doubt it arises in the dimerization by 1,4-addition of water, present in trace amounts on the glass surface of the reactor. The dimer when pure reacts with water readily to produce (149), and bromine has been shown to add in a similar 1,4-fashion across the dimer s conjugated system(see Scheme 40). ... 

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