Perfluoroalkyl halides derivatives

Other sulfonate derivatives are obtained by the use of trifluoromethanesulfonyl hypochlorite and hypobromite (CF3S020C1 and CF3S020Br) in reactions with perfluoroalkyl halides and their derivatives [30]. These reactions lead to the corresponding trifluoromethanesulfonate derivatives of alkanes (equation 28) (Table 11). The reaction proceeds with complete retention of stereochemistry at the carbon center [30]. 

The first successful syntheses utilizing trifluoromethyl iodide in transition metal chemistry were reported by Stone and his students. Stone reasoned that if CF3I would not react with transition metal anions to form trifluoromethyl derivatives [see Eq. (3)] then perhaps compounds containing perfluoroalkyl substituents could be generated by the oxidative addition of perfluoroalkyl halides to low valent transition metal substrates (9,10). The first reported trifluoromethyl-substi-tuted transition metal complex prepared by this route is shown in Eq. (4) (41). 

Reactions of perfluoroalkyl halides with heterocyclic derivatives 00UK538. 

Perfluoroalkylcopper compounds, derived from perfluoroalkyl halides and copper in dipolar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylacetamide, are rather stable. These complexes couple effectively with aryl and vinyl halides (Burdon et al., 1967, 1972a McLoughlin and Thrower, 1969). 

Unlike alkyl halides, perfluoroalkyl halides do not give perfluoroalkyl derivatives when they react with metal carbonyl anions. 

The 1,4-dinucleophilic building blocks used most are 1,2-disubstituted ethanes of the type HXCHiCHjYH, semicarbazides, thiosemicarbazides, hydroxamic acid amides, amidrazones, and 1,2-disubstituted aromatic and heteroaromatic compounds. 1,1-Dielectrophilic building blocks preferentially used are perfluorinated carboxylic acids and their derivatives, such as acid halides, anhydrides, imidoesters, nitriles, perfluoroalkyl chlorosul-... 

Other functional polyfluorinated compounds are available by addition of perhaloalkyl halides to enol derivatives, e.g. formation of 1 and 2 (see also Table 4). The adducts formed from enol acetates or enol ethers are not very stable and their hydrolysis to give a-perhaloalkyl aldehydes or ketones is often rapid. However, the enol derivatives can be transformed either to give ketals using alcohols or to give various products by oxidation and reduction reactions. The peculiar perfluoroalkyl iodide addition to enamines is spontaneous at room temperature, e.g. formation of 3. ... 

Synthesis of triazolo[4,3-fl pyrimidines via reaction of hydrazonyl halides with ethyl 3,4-dihydropyrimidine-5-carboxylate derivatives has been described <04PS601>. Synthesis of perfluoroalkyl[l,2,4]triazolo[l,3]thiazinones has been reported <04JGU472>. 

Barr, D.A. Haszeldine, R.N. Perfluoroalkyl derivatives of nitrogen. VII. Reactions of nitrosyl halides with tetrafluoroethylene. J. Chem. Soc. 1960, 1151-1155. 

The trifluoromethylation of aryl iodides has been achieved using the reaction with (trifluoromethyl)-trimethoxyborate and a copper(I)/phenanthroline catalyst." A copper chloride/phenanthroline catalyst has also been used together with (TMP2Zn), zinc bis-tetramethylpiperidide, in the reaction of aryl iodides with perfluoroalkyl derivatives to yield arylperfluoroalkanes. The mechanism is thought to involve initial formation of bis(perfluoroalkyl)zinc species followed by rate-limiting transmetalation with copper halide and reaction with the aryl iodide to give the coupled product." ... 

Mn(CO)5] reacts with allyl halides at room temperature to produce the hexacoordinate a-allyl derivative C3H5Mn(CO)5 which must be heated to 60° C before carbon monoxide is lost at an appreciable rate to form the ir-allyl derivative C3HsMn(CO)4 (99,100). In addition, the pentacoordinate perfluoroacyl derivatives of cobalt, RfCOCo(CO)4 (38, 111, 112), lose carbon monoxide to form RfCo(CO)4 at a lower temperature than the hexacoordinate perfluoroacyl derivatives of manganese, RfCOMn(CO)5 (38,113), form the perfluoroalkyl derivatives, RfMn(CO)s. On the basis of present data, however, it is diflicult to separate the effect of coordination number on the general stability of the molecule from the effect of coordination number on the stability of the metal-carbon monoxide bond. 

No stable compounds of the type R2Fe(CO)4 with iron-carbon a bonds have been isolated by the reaction between [Fe(CO)4] and alkyl halides such as methyl iodide. However, the perfluoroalkyl derivatives (Rf)2Fe (CO)4 (Rf = C2F5 and C3F7) have been obtained as air-stable very pale yellow crystals by the reaction between Na2[Fe(CO)4] prepared in tetra-hydrofuran and the perfluoroacy/ chlorides RfCOCl. The intermediate perfluoroacyl derivatives (RfCO)2Fe(CO)4 were not isolated, but instead were decarbonylated spontaneously in the boiling tetrahydrofuran 50). For reasons which are not clear at the present time the yields of the perfluoroalkyl compounds (Rf)2Fe(CO)4 in this reaction were only about 15%. Attempts to prepare (CF3)2Fe(CO)4 by this technique have been unsuccessful. A related compound is the extremely stable perfluorotetramethylene derivative C4FgFe(CO)4 (XXIX) 182) obtained from tetrafluoroethylene and iron pentacarbonyl. This fluorocarbon derivative was first erroneously formulated as a tricarbonyl derivative 183). 

Aldehydes, ketones and esters of general formula 708 reacted with amidines to give pyrimidine derivatives (Table 40, Entries 1-4). Analogous methods were developed for (per)fluorinated vinyl halides 709 (Entry 5) and 710 (Entries 6, 7). Analogous reaction was successful with enol phosphate 814, obtained from ketone 813 and sodium diethyl phosphite (Scheme 162) [120], In aU these cases, nucleophilic substitution of two fluorine atoms at a-carbon of the perfluoroalkyl group occurred. 

Carbon monoxide evolution and formation of perfluoroalkyl derivatives directly is also observed when alkali metal salts of cobalt carbonyl are treated with perfluoroacyl halides or anhydrides at ambient temperatures (95,100, 101). 

Perfluoroacyl halides readily form perfluoroacyl-metal complexes, M—CORf, from which the perfluoroalkyl derivatives are easily prepared by decarbonylation, e.g. 

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