Alkenes fluoro

The alkyne (15 mmol) is added to TBA-H2F3 (9 g, 30 mmol) in Cl(CH2)2Cl (l ml) and the mixture is protected from atmospheric moisture and heated until the reaction is complete. H20 (5 ml) is added and the mixture is extracted with Et20 (3 x 10 ml). The extracts are washed with H,0 to pH 5, dried (Na2S04), and evaporated to yield the Z- and f-fluoro-alkenes [e.g. MeOCOCF=CHC02Me (60°C, 30 h), 80% PhCF=CHC02Me (120°C,... 

STEREOSELECTIVE SYNTHESIS OF 2,2-DISUBSTITUTED 1-FLUORO-ALKENES (E)-[lFLUORO(2-PHENYLCYCLOHEXYLlDENE)-... 

Hydroxy-1,2-dicarboxylic acids, such as n- and L-a-hydroxysuccinic acid53 and D-tartaric acid.120 on treatment with sulfur tetrafluoride give complex mixtures of fluoroalkanes, fluoro-alkenes, fluoroalkyl fluorosulfites and cyclic five-membered ethers, derivatives of 2.2,5.5-tet-rafluorotetrahydrofuran. In the case of D-tartaric acid the cyclic ethers are predominant components (64%) of the reaction mixture.120 Linear and cyclic mono- and disulfites formed in these reactions give, after hydrolysis, the corresponding linear and cyclic polyfluoro alcohols and diols in high yield.53120... 

The well-known /(-elimination of fluoride from perfluoroalkylmetal compounds to fluoro-alkenes, which demands the handling of magnesium and lithium derivatives of this type at low temperatures (or formation as intermediates), is mentioned in Section 3.3.1. 

Me2 AsH and the perfluorocycloalkene by addition/elimination.133 Fluoroaliphatic diarsines may be obtained from the addition of tetramethyldiarsine to fluoro-alkenes or -alkynes (equations 38 and 39).134... 

However, systems with vinylic iodine do not undergo nucleophilic substitution when reacted with LiAlH4 but form aluminium complexes in solution. Hydrolysis of these mixtures with D20 is a convenient route to deuterated fluoro-alkenes [125] (Scheme 58). 

As noted in both radical and redox mechanisms of telomerisation of fluoro-alkenes, termination reactions always occur by recombination and not by disproportionation [29]. 

Concerning hypohalites, CTFE seems very efficient in contrast to other fluoro-alkenes which have led to monoadduct mainly. The reaction is as follows ... 

The dynamical theory has satisfactorily reproduced the proportions of reverse critical energy partitioned into translation in the elimination of HF from the molecular ions of a number of fluoroalkanes and fluoro-alkenes [167], One broad conclusion was that, in the decompositions studied, late transition states tended to favour partition of reverse critical energy into translation, whereas early transition states did not, cf. late and early downhill [285] (see Sect. 8.4.2). Constraints due to conservation of angular momentum were also evident. 

Another variant of this type reaction has recently been utilized by Novartis to manufacture an intermediate for Prosulfuron (see Table 1.1). The synthetic scheme is shown by reaction 7.32. The soluble palladium-complex-catalyzed C-C coupling between a diazonium salt and a fluoro alkene gives the required intermediate. This is then converted to the final product by standard reactions of synthetic organic chemistry. 

The only other route to scandium fluoride derivatives has been via C—F bond activation of fluoro-alkenes with [ScR(Cp )2] (R = H, Me) to give [ScF(Cp )2] [1], Very recent work has produced the first report of an organometallic yttrium fluoride. The reaction between [(CsH5)3Y] and Me3NHF results in the isolation of [ (C5H5)2YF(THF) 2] which has been fully characterised by elemental analysis, infra-red, mass and NMR spectroscopies and X-ray diffraction [8]. 

When trialkylphosphites are treated with fluoroalkanoyl chlorides, perhalogenated fluoro-alkenes, perfluorinated aromatics, and other fluorinated alkylating substrates, an Arbuzov reaction takes place and alkyl fluorides are formed as byproducts. The method has been used to prepare 6-fluoro-6-deoxy-l,2 3,4-di-f7-isopropylidenegalactose (1). ... 

Fluoroalkene Vmol ( BuO)2 ( mmol) Vessel8 Temp ( C) Time (h) Fluoro- alkene Con- sumed (%) % /prRp RO OR RK Yield11 (%) bp ( C/Torr)... 

Nakamura, Y., Okada, M., Koura, M., et al. (2006) An efficient synthetic method for Z-fluoro-alkene dipeptide isosteres application to the synthesis of the dipeptide isostere of Sta-Ala. J. Fluorine Chem., 127, 627-636. 

Otaka, A., Watanabe, H., Yukimasa, A., et al. (2001) New access to a-substituted (Z)-fluoro-alkene dipeptide isosteres utilizing organocopper reagents under reduction-oxidative alkylation (R-OA) conditions. Tetrahedron Lett., 42, 5443-5446. 

A new method of fluoro-olefin synthesis involves initial reaction of the ylide-salt (60) with perfluoroacyl fluorides to give vinylphosphonium salts (61), rather than the acylation products. Alkaline hydrolysis of (61) gives ( )-fluoro-alkenes (Scheme 8). The reaction of non-stabilized ylides with chlorodifluoro-... 

As in Volumes 1 and 2, no attempt has been made to draw together information on reactions believed to involve transient per- or poly-fluoroaliphatic derivatives of Na, K, Rb, or Cs generated, for example, via attack of the corresponding metal fluorides on fluoro-alkenes or -alkynes. 

Johnson et al found that a tetrasubstituted fluoro alkene could be prepared with modest alkene stereoselectivity by rearrangement of a tertiary acetate ester (Scheme 4.103) [94]. Surprisingly, the major product was the E-isomer. This impUes that the transition state with the nominally larger CH2CH2R group in the pseudo-axial position is favored. The corresponding Johnson-Claisen gave a 1 1 E Z mixture. 

Activation parameters have been measured for the rearrangement of the fluoro-alkene complexes (2) to the alkenyl complexes (3). The results (Table 2) indicate that... 

Reaction of /ra 5-[M(CO)3L2], where M = Fe or Ru and L = phosphine or phosphite, with fiuoro-alkenes usually produces, under photochemical conditions, M(CO)2(fluoro-alkene)L2, though the compound with M = Fe and L = triethyl phosphite reacts with two molecules of trifluoroethylene to yield (3). These results can all be accommodated by a reaction scheme in which replacement of carbon monoxide by fluoro-alkene produces an ionic intermediate (4) which can either ring-close or... 

Irradiation of hexane solutions containing /ru 5-[M(CO)3L2], where M = Fe or Ru and L is a phosphine or phosphite, and fluoro-alkenes usually results simply in the formation of a fluoro-alkene complex, but reaction of /rans-[Fe(CO)3 P(OEt)8 8] with CF8=CFH produces the compound (35). Both reactions can be explained by formation of a common ionic intermediate (36), as shown in Scheme 6. A similar situation prevails for reactions of hexafluorobut-2-yne with these complexes trans-[M(CO)sL8]. Here the suggested ionic intermediate is the species (37). A... 

Model Calculations of A-factors by Transition State Theory The A-factors for addition of CF (39) and CH3 (40) radicals to fluoro-alkenes have been calculated by transition state theory using the expression derived by Herschbach, Johnston, Pitzer and Powell (52) ... 

Ichikawa J (2007) Construction of fluorinated heterocycles intramolecular substitution and addition of fluoro alkenes. Chim Oggi 25(4) 54-57... 

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