Tris methane, reaction with

Alkynes substituted with one or two trifluoromethyl groups are also highly reactive dienophiles [9] Indeed, hexafluoro-2-butyne is used increasingly as a definitive acetylenic dienophile in "difficult Diels-Alder reactions. It was used, for example, to prepare novel inside-outside bicycloalkanes via its reaction with cir,trnns -l,3-undecadiene [74] (equation 67) and to do a tandem Diels-Alder reaction with a l,l-bis(pyrrole)methane [75] (equation 68) Indeed, its reactions with pyrrole derivatives and furan have been used in the syntheses of 3,4-bis(tri-fluoromethyl)pyrrole [76, 77] (equation 69) and ],4-bis(trifluoromethyl)benzene-2,3-oxide [78] (equation 70), respectively. 

Dimethyl ether, methylation by diazo-methane and 2,4,6-trinitroben-zenesulfonic acid to form tri-methyloxomum 2,4,6-tnmtroben zenesulfonate, 46,123 reaction with tnethyloxonium fluo-borate, 46,120... 

Tris(4-hthiophenyl)methane (76), a l,9,9 -trilithiated compound, was obtained by Oda and coworkers . The starting tribromo compound 75 reacts with three equivalents of w-butyUithium in THF at low temperatures. Trapping reactions with various electrophiles resulted in yields between 59 and 90% (Scheme 27). 

Fluorination of tris(fluorosulfonyl)methane (10) with xenon difluoride in dichlorodifluoro-methane solution gives fluorotris(fluorosulfonyl)methane in quantitative yield.24 In contrast, no fluorination product has been obtained in the reaction of tris(trifluoromethylsulfonyl)meth-ane with xenon difluoride.25... 

However, the reaction of tri-a-butylarsine oxide with dibenzoyl-methane or with dimethyl malonate in triethylamine and in the presence of phosphorus pentoxide gave the corresponding ylides (11), respectively, (20, 40). 

Xenon difluoride reacts also with some halosubstituted alkanes18,19 at room temperature in chloroform, carbon tetrachloride, dichloromethane or bromoform, and depending on the nature of the solvent used chloro or bromo derivatives are isolated with imidazo-(l,2-fr)-pyridazine18. Carbon tetrachloride reacts with xenon difluoride at 180°C, while room-temperature transformations are achieved when various catalysts [antimony trifluoride, tantalum(V) fluoride or silica dioxide] are used, whose structure also influences the product distribution20. Tris(fluorosulfonyl)methane gives a fluoro-substi-tuted product in its reaction with xenon difluoride in difluorodichloromethane21. 

Using the same reaction procedure described in the direct reaction of elemental silicon with methylene chloride or chloroform, the reaction of elemental silicon with a gaseous mixture of tetrachloromethane and hydrogen chloride afforded no tetrakis(chlorosilyl)methane instead, tris(chlorosilyl)methanes and bis(chlorosilyl)methanes were obtained, which were the same products derived from the reactions of chloroform and methylene chloride, respectively. This result may be rationalized by the decomposition of tetrachloromethane to chloroform and methylene chloride on the silicon-copper contact mass during the reaction, followed by reaction with elemental silicon to afford the products or by the decomposition reaction of partial silylated chloromethane intermediates.16... 

Catalytic transformations involving the C-H bonds of thiophene are rare, but recently there has been a report on the catalytic addition of the C(2)-H bond of thiophene across ethylene to form 2-ethylthiophene <20040M5514>. Reaction of the ruthenium complex TpRu(CO)(NCMe)(Me) (where Tp = hydrido tris(pyrazolyl)borate) with thiophene produces the 2-thienyl complex 249 and methane. This complex catalyzes the formation of 2-ethylthiophene from a solution of thiophene and ethylene (Equation 121). The mechanism of this reaction has been explored. 

OL-Keto lactones. Lactones can be converted into a-keto lactones by conversion to an enamino lactone by reaction with tris(dimethylamino)methane followed by photooxidation in CH2CI2 at - 78°. The a -keto lactones exist mainly or exclusively in the enol form and do not undergo normal Wittig condensation. 

Brown ei al. now find that tri-/i-butylcarbinol is obtained in essentially quantitative yield by the reaction of tri-n-butylborane with chlorodifluoromethane (or other tri-substituted methanes) under the influence of lithium triethylcarboxide (equation 2). 

Methylquinoxalin-2(l//)-one undergoes reaction with tris(dimethylamino)methane to yield 3-[( )-jS-dimethylaminovinyl]quinoxalin-2(l//)-one... 

The tri-chlorine substitution product of methane is the common and very important anesthetic chloroform. It may be made by the method referred to, viz., by the direct chlorination of methane. This method is not, however, a practical one. The industrial preparation is from alcohol or acetone, by treatment with chlorine and an alkali. In the reaction with alcohol the chlorine acts, first, as an oxidizing agent, oxidizing the alcohol to aldehyde. The chlorine then acts as a substituting agent forming a tri-chlorine substitution product of the aldehyde. This tri-chlor aldehyde is then decomposed by the alkali and chloroform results. The steps in this reaction have been definitely proven, as follows ... 

The intermediate tris(methylimino)methane biradicals were trapped in a high yield as the products of the reactions with solvents <69JOC2994> they were also detected by ESR spectra in a low-temperature matrix (78JA1306). 

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