Chlorotris

Kel-F Trade name for a polymeric chlorotri-fluoroethene, often copolymerized. May be a liquid or solid. Inert to chemical attack and a thermoplastic (Teflon cannot be moulded). 

Halpern J, Okamoto T and Zakhariev A 1976 Mechanism of the chlorotris(triphenylphosphine)rhodium(l)-catalyzed hydrogenation of alkenes J. Mol. Catal. 2 65-9... 

Unfortunately, the thermodynamically favored reactions of trichlo-rolluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12) with water do not proceed to a significant degree below 300 C and at least 200 atm (1 atm = 101.325 kPa) or greater [42] (equation 44) Even at 4000 atm randoimzation rather than complete hydrolysis occurs, leaving another chlorofluorocarbon, chlorotri-fluoromethane (CFC-13), which is also potentially harmful to the earth s ozone layer... 

Perfluoroalkyl- and perfluoroaryltitanium compounds were prepared m situ via reaction of the corresponding Gngnard reagents with chlorotris(diethyl-amido)titanium [28S] Reaction of the titanium compounds with aldehydes resulted in fluoroalkylative amination [288] (equation 192)... 

The behavior of strained,/Zuorimiret/ methylenecyelopropanes depends upon the position and level of fluorination [34], l-(Difluoromethylene)cyclopropane is much like tetrafluoroethylene in its preference for [2+2] cycloaddition (equation 37), but Its 2,2-difluoro isomer favors [4+2] cycloadditions (equation 38). Perfluoromethylenecyclopropane is an exceptionally reactive dienophile but does not undergo [2+2] cycloadditions, possibly because of stenc reasons [34, 45] Cycloadditions involving most possible combinations of simple fluoroalkenes and alkenes or alkynes have been tried [85], but kinetic activation enthalpies (A/f j for only the dimerizations of tetrafluoroethylene (22 6-23 5 kcal/mol), chlorotri-fluoroethylene (23 6 kcal/mol), and perfluoropropene (31.6 kcal/mol) and the cycloaddition between chlorotnfluoroethylene and perfluoropropene (25.5 kcal/mol) have been determined accurately [97, 98] Some cycloadditions involving more functionalized alkenes are listed in Table 5 [99. 100, 101, 102, 103]... 

Pyrolysis studies have often been applied to chlorotnfluoroethylene and tetrafluoroethylene Pyrolysis of chlorotnfluoroethylene at 560-590 °C yields 70-83% of a mixture containing both linear and cyclic dimers of chlorotri... 

The addition of aziridinyl anions to aldehydes gave the alcohols 31 in good yields15. As with the oxiranyl anions, the diastereoselectivity of the addition reaction could be substantially enhanced by transmetalation of the lithium reagent with chlorotris(dimethylamino)titanium. 

The lithiated anion was transmetalat-ed with 1 equivalent of chlorotris(di-methylaminoftitanium. 

Chlorotris(diethylamino)titanium24 is prepared directly from diethylamine, lithium and tilani-um(IV) chloride in the presence of styrene as reducing agent25. However, a metathesis reaction between tetrakis(diethylamino)titanium26 28 and titanium(lV) chloride gives a cleaner product and is thus preferred. Bromotris(diethylamino)titanium is prepared similarly7,29. 

Chlorotris(dimethylamino)titanium has the advantage that the starting material, tetrakis(di-methylamino)titanium, is commercially available24. 

The lithium-TMEDA complex 1, obtained by deprotonation of (S)-(E)-1 -methyl-2-butenyl diisopropylcarbamate (84% ee), affords, after metal exchange by tetraisopropoxytitanium and addition to 2-methylpropanal, the homoaldol adduct ( + )-4 with 73% ee, whereas (-)-4 (53 % ee) is obtained when chlorotris(diethylamino)titanium is used104. 

The reagents prepared by lithiation (see Section 1.3.3.3.1.2.) and titanium exchange of (S)-(Z)-l-methyl-2-butenyl diisopropylcarbamate106 show a diminished reactivity when compared with those derived from the ( -isomer, indicating that in both metalation steps the doublebond geometry is retained16. After treatment of the lithium -TMEDA complex with chlorotris-(diethylamino)titanium and 2-methylpropanal, the homoaldol adduct (3S,47f)-(Z)-4-hydroxy-1,3,5-trimethyl-l-hexenyl diisopropylcarbamate [( + )-4], is formed with 88% ee16. 

Only few allyltitanium reagents bearing a removable chiral auxiliary at the allylic residue are known. The outstanding example is a metalated 1-alkyl-2-imidazolinone14, derived from (—)-ephedrine, representing a valuable homoenolate reagent. After deprotonation by butyllithium, metal exchange with chlorotris(diethylamino)titanium, and aldehyde or ketone addition, the homoaldol adducts are formed with 94 to 98% diastereoselectivity. 

A solution of 0.11 mol of 1.5M butyllithium in hexane is added to 30 mL of THF under a layer of argon or nitrogen at —78 C, followed by 0.10 mol of (4S,5/ )-1-allyl-3,4-dimcthyl-5-phenyl-2-imidazolidinone in 75 mL of THF. After 25 min, a solution of 0.11 mol of chlorotris(diethylamino)titanium in 30 mL of THF is introduced. The mixture is stirred at — 20 °C for 45 min, then 0.11 mol of the aldehyde or ketone in 10 mL of THF is added. After 2 h. 20 mL of water and 200 mL of diethyl ether are added. The ethereal solution is separated, washed with 20 mL of 10% aq NaHS03 followed by 20 mL of water, dried over Na2S04 and concentrated, whereupon the product crystallizes. Diastereomerically pure samples are prepared by recrystallization from hexane or hexane/ethyl acetate. 

A mixture of 40 mmol or the a-nitro alcohol 1, 48 mmol of (terf-butyldimethyl)chlorosilane or chlorotri-mcthylsilanc, 6.8 g (100 mmol) of I /(-imidazole and 10 mL of DMF is stirred at 20 C for 12 h. Water is added and the mixtnre is extracted with hexane. The combined extract is washed wilh water and sat. aq NaCl and dried over MgS04. Exaporation gives the O-silyl nitro alcohol as an oil which is distilled (bulb-to-bulb) yield 45 - 97%. If unreacled starting material is present in the distillate, it can be removed by chromatography over silica gel (30 g/ l g of product) with l,t,0/pcntanc 1 9 as eluant. 

Weathering Many plastics has short lives when exposed to outdoor conditions. The better materials include acrylic, chlorotri-fluorethylene, vinylidene fluoride, chlorinated polyether, polyester, alkyd, and black linear poly-ethylene. Black materials are best for outdoor service. Some of the styrene copolymers are suitable for certain outdoor uses (Chapter 2, WEATHERING/ ENVIRONMENT). 

Chlorotris(triphenylphosphine)rhodium(I) its chemical and catalytic reactions. F. H. Jardine, Prog. Inorg. Chem., 1981, 28, 63-202 (650). 

Tin, bis(diethyldithiocarbamato)diphenyl-angular parameters, 1,57 Tin, bis(diethyldithiocarbonato)diiodo-angular parameters, 1,57 Tin, bis(diethyl dithiophosphate)diphenyl-stereochemistry, 1,59 Tin, bis(diethyldithiophosphonium)diiodo-angular parameters, 1, 57 Tin, chlorotris(tropolone)-stereochemistry, 1, 82 Tin, cyclopentadienyl-, 3, 218 Tin, dibromobis(ethyldithiocarbonato)-angular parameters, 1, 57 Tin, dichlorobis(ethyldithiocarbonato)-angular parameters, 1, 57 Tin, dimethylbis(acetylacetone)-structure, 1, 58... 

Aldehydes, both aliphatic and aromatic, can be decarbonylated by heating with chlorotris(triphenylphosphine)rhodium or other catalysts such as palladium. The compound RhCl(Ph3P)3 is often called Wilkinson s catalyst.In an older reaction, aliphatic (but not aromatic) aldehydes are decarbonylated by heating with di-tert-peroxide or other peroxides, usually in a solution containing a hydrogen donor, such as a thiol. The reaction has also been initiated with light, and thermally (without an initiator) by heating at 500°C. 

Acyl chlorides containing an a hydrogen are smoothly converted to alkenes, with loss of HCI and CO, on heating with chlorotris(triphenylphosphine)rhodium, with metallic platinum, or with certain other catalysts. The mechanism probably involves conversion of RCH2CH2COCI to RCH2CH2—RhCO(Ph3P)2Cl2 followed by a concerted syn elimination of Rh and H. See also 14-39 and 19-12. 

Uson, R., Lagrma, A., Laguna, M., Fernandez, E., Villacampa, M.D., Jones, P.G. and Sheldrick, G.M. (1983) Mono-, bi-, and trinuclear bis (diphenylphosphino)methanegold complexes. Crystal and molecular structures of [bis(diphenylphosphino) methane]bis(pentafluorophenyl)gold(lll) perchlorate and 1,2 2,3-di- X-[bis (diphenylphosphino) methane] -1,3-dichlorotrigold(l) chlorotris (pentafluorophenyl)aurate(lll). Journal of the Chemical Society, Dalton Transactions, (8), 1679-1685. 

Bardaji, M., Laguna, A. and Vdlacampa, M.D. (2000) Bis[bis(diphenylphos-phrnomethyl)phenylphosphine] dichlorotetragold(I) bis[chlorotris (pentafluorophenyl)aurate(lll)]. Acta CrystaUographica, Section C Crystal Structure Communications, C56(ll), E487-E488... 

E. Mallat, C. Barzeb, A. Klotz, A. Brecht, G. Gauglits, and D. Barcelo, River Analyzer for chlorotri-azines with a direct optical immunosensor. Environ. Sci. Technol. 33, 965—971 (1999). 

The diester 226 undergoes ring-closure to the methylenecyclopentane derivative 227 in the presence of a catalytic amount of chlorotris(triphenylphosphine)rhodium in boiling chloroform saturated with hydrogen chloride. In contrast, if the reaction is catalysed by palladium(II) acetate, the isomeric cyclopentene 228 is produced (equation 115)118. 

In the presence of titanium bis(TADDOLate)s such as 51 and 52 (25 mol%), generated from titanium tetraisopropoxide and the corresponding TADDOL, as well as chlorotri-... 

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