Tetrakis trifluoromethyl

Cyclic and Polymeric Substances Containing Arsenic—Arsenic Bonds. A number of organoarsenic compounds containing rings of four, five, or six arsenic atoms have been prepared (cycHc polyarsines). The first such four-membered ring compound to be adequately characterized, tetrakis (trifluoromethyl) tetrarsetane [7547-15-17, was obtained by the interaction of a diiodoarsine and mercury (107,108) ... 

A few special syntheses of thiirane derivatives from four-membered sulfur heterocycles are known. Methylenethiiranes are derived by thermolysis of the tosylhydrazones of thietan-3-ones (Scheme 143) (81TL4815), and 2,2,3,3-tetrakis(trifluoromethyl)thiirane is obtained by thermolysis of 2,2,4,4-tetrakis(trifluoromethyl)-l,3-dithietane 1,1-dioxide with loss of sulfur dioxide. 2,2,3,3-Tetrakis(trifluoromethyl)thiirane 1,1-dioxide is obtained in low yield by heating a mixture of 3,3-bis(trifluoromethyl)-l,2,4-oxadithietane 2,2,4,4-tetroxide and bis(trifluoromethyl)ketene. The mono-episulfide of norbornadiene is obtained from thietane derivative (65 Scheme 144) (73JOC649). 

The stable Dewar thiophene (68) is obtained by irradiation of 2,3,4,5-tetrakis(trifluoromethyl)thiophene (Scheme 150) (72ClC272l). Dewar thiophenes are proposed as intermediates in the photochemical isomerizations of substituted thiophenes (Scheme 17). 

Thiophene, 2,3,4,5-tetrakis(trifluoromethyl)-irradiation, 7, 181 Thiophene, tetramethyl-reactions... 

Tetrakis(trifluoromethyl)dithietane is generated by dimerization of hexa-fluorothioaeetone which is prepared in situ from hexafluoiopropylene with potassium fluoride and sulfur [189] or with sulfur and antimony pentafluoride [190] (equation 27)... 

Lastly, a termolecular cydization of unknown mechanism provides a useful synthesis of tetrakis(trifluoromethyl)thiophene 60 (equation 60)... 

Photolysis of 2,3,5,6-tetrakis(trifluoromethyl)-l,4-di hoshabenzene gives 1,3,4,6 tetrakis(tnfluoromethyl)-2,5-diphosphatncyclo[3 1 0 0 ]hex-3-ene, an ana logue of benzvalene containing phosphorus atoms in the ring system [267, 16S] (equation 40)... 

Tin tetraiodide was placed in a quartz boat which was then positioned at the tail of the plasma. Tetrakis(trifluoromethyl)tin was syn-... 

An ylide (58) is formed when tetrakis(trifluoromethyl)cyclopenta-dienone and triphenylphosphine are mixed in dichloromethane. ... 

Keywords Cation-radical salts, Molecular conductors, Organic superconductors, Organometallic anions, Tetrakis(trifluoromethyl)metallates, Tetrathiafulvalene... 

Perfluoroalkylgermanium derivatives, like tetrakis(trifluoromethyl)germanium, can be prepared by fluorination of organogermanium compounds280 ... 

The numerous transformations of cyclooctatetraene 189 and its derivatives include three types of structural changes, viz. ring inversion, bond shift and valence isomerizations (for reviews, see References 83-85). One of the major transformations is the interconversion of the cyclooctatetraene and bicyclo[4.2.0]octa-2,4,7-triene. However, the rearrangement of cyclooctatetraene into the semibullvalene system is little known. For example, the thermolysis of l,2,3,4-tetra(trifluoromethyl)cyclooctatetraene 221 in pentane solution at 170-180 °C for 6 days gave three isomers which were separated by preparative GLC. They were identified as l,2,7,8-tetrakis(trifluoromethyl)bicyclo[4.2.0]octa-2,4,7-triene 222 and tetrakis(trifluoromethyl)semibullvalenes 223 and 224 (equation 71)86. It was shown that a thermal equilibrium exists between the precursor 221 and its bond-shift isomer 225 which undergoes a rapid cyclization to form the triene 222. The cyclooctatetraenes 221 and 225 are in equilibrium with diene 223, followed by irreversible rearrangement to the most stable isomer 224 (equation 72)86. 

With slight modification, the methods used to prepare fluorothioacyl fluorides can also be used for synthesis of fluorothioketones. Hexafluorothioacetone, the member of this class that has been studied most extensively, is readily obtained by high-temperature reaction of hexafluoropropylene and sulfur (53). The thio-ketone is a deep-blue liquid, bp 8° C, that dimerizes on standing to 2,2,4,4-tetrakis-(trifluoromethyl)-l,3-dithietane. 

Fluorothioketones are more difficult to polymerize. There are two reasons. First, agents that promote polymerization also catalyze dimerization to dithi-etanes, which is a very fast reaction. Second, ceiling temperature of polymerization is low with the result that polymer decomposes back to monomer as it is being isolated. However, poly(hexafluorothioacetone) can be formed at very low temperatures by initiation with dimethylformamide or BF3 etherate, even though at — 78° C the only product isolated is 2,2,4,4-tetrakis(trifluoromethyl)-l,3-di-thietane. 

Tetrakis(trifluoromethyl)-l,3-dithietanes react with nucleophiles to give products expected from monomeric bis(trifluoromethyl)thione. In fact, fluoride ion in DMF produces monomer (76BCJ2491), anilines give imines, and phenylhydrazine gives hydrazone (73BCJ3260). Triphenylphosphine gives a Wittig ylide that reacts with aldehydes to produce... 

An interesting dimer derived from tetrakis(trifluoromethyl)cyclobutadiene 40 is obtained by photolysis of an ozonide precursor. The diene is stable at — 196°C but forms dimer 41 upon... 

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