Acetylene, fluoro

Electrochemically generated trifluoromethyl radicals add to 1-hexyne to give a 1 4 mixture of ( )- and (Z)-l,l,l-trifluoro-2-heptene [22] Kinetic data on the addition of photochemically generated trifluoromethyl radicals to acetylene and substituted acetylenes were reported [2J]. Alcohols and aldehydes add to hexa-fluoro-2-butyne in the presence of peroxide and y-ray initiation [24] (equations 16 and 17). 

Examples of perfluoroalkyl iodide addition to the triple bond include free radical addition of perfluoropropyl iodide to 1 -heptyne [28] (equation 21), thermal and free radical-initiated addition of lodoperfluoroalkanesulfonyl fluorides to acetylene [29] (equation 22), thermal addition of perfluoropropyl iodide to hexa-fluoro 2 butyne [30] (equation 23), and palladium-catalyzed addition of per-fluorobutyl iodide to phenylacetylene [31] (equation 24) The E isomers predominate in these reactions Photochemical addition of tnfluoromethyl iodide to vinylacetylene gives predominantly the 1 4 adduct by addition to the double bond [32] Platinum catalyzed addition of perfluorooctyl iodide to l-hexyne in the presence of potassium carbonate, carbon monoxide, and ethanol gives ethyl () per fluorooctyl-a-butylpropenoate [JJ] (equation 25)... 

Fluormation likewise significandy destabilizes the multiple bonds in allenes and acetylenes [105] Fluoro- and difluoroacetylene are dangerously explosive, and hexafluoro-2-butyne is very susceptible to both concerted and biradical addition reacbons [106, 107] (see pp 757 and 767)... 

The fruit of a shrub that grows in Sierra Leone is very toxic and has been used as a rat poison. The toxic principal has been identified as Z-18-fluoro-9-octadecenoic acid. Suggest a synthesis from 8-fluorooctanol, l-chloro-7-iodoheptane, acetylene, and any other necessary organic or inorganic reagents. 

Methyl trifluorovinyl ether, b.p. 10.5- 12.5°C, prepared from tetrafluoroethylene and sodium methoxide [1], has considerable explosive potential. On ignition, it decomposes more violently than acetylene and should be treated with extreme caution [2], Other trifluorovinyl ethers are similarly available from higher alkoxides [1], and although not tested for instability, should be handled carefully. Presence of fluoro-haloalkanes boiling lower than the ether stabilises the latter against spark-initiated decomposition in both fluid phases [3],... 

The acetylenic bond of propargyl ethers can react with polynitroaliphatic alcohols, as in the case of ethoxyacetylene (125), which reacts with two equivalents of 2-fluoro-2,2-dinitroethanol (119) to give the orthoester (126). " ... 

The course of the reaction of hypofluorous acid with acetylenes in carbon tetrachloride at — 50 C depends on the structure of the acetylene phenylacetylene (6, R = Ph) gives 2-fluoro-1-phenylethanone and phenylacetyl fluoride, while 3,3-dimethylbut-l-ync (6, R = -Bu) gives 2-fluoro-3,3-dimethylbutanal in 60% yield.6... 

The nonfluorinated tertiary acetylenic alcohol 2-methylbut-3-yn-2-ol (13) reacts explosively to give a mixture of 3-fluoro-3-methylbut-l-yne and 2-methylbut-l-en-3-yne.56... 

It should be noted that compounds of the prismane, Dewar and benzvalene type above have been produced nonphotochemically by the trimerization of /-butyl fluoro-acetylene to give structures 9-H.ss.58... 

Martin, S. Sauvetre, R. Normant, J.-F. Reaction de perhalostyrenes avec les organo-lithiens. Preparation d aryl-l-alcynes-1 ramifies par l intermediaire d aryl fluoro acetylenes. Tetrahedron Lett. 1982, 23, 4329-4332. 

Benzimidazoles, 2,3-dihydro-, by Nu addition at C-2, 56, 203 Benzimidazole, 2-fluoro-, 59, 272 Benzimidazole, 1-methyl-, ring expansion to chloroquinoxalines, 59, 305 Benzimidazole, l-methyl-2-(5 -methyl-2 -thienyl)-, bromination, 57, 319 Benzimidazole 3-oxides, chloro-deoxygenation, 59, 270 Benzimidazoles, 2-perfluoroalkyl-, 60, 25 Benzimidazoles, 2-(l-pyridinio)-, 60, 204 Benzimidazoles, 2-(2-pyridinioethyl)-, elimination reactions, 60, 246 Benzimidazoles, tetrafluoro-, 59, 14 Benzimidazole-2-carboxylic ester 3-oxide, 7-nitro-5-trifluoromethyl-, 60, 17 Benzimidazolium salts, l-amino-3-alkyl-, reaction with activated acetylenes, 56, 138... 

Besides processes (1) and (2), the reader should be aware that nucleophilic attacks on alkynes are treated in other chapters of this book, dealing with rearrangements, cyclizations, polyacetylenes, cyclic acetylenes and perhaps others. A number of publications overlap with ours in different ways and at different levels -. They treat individual alkynes or families " , e.g. acetylene, diacetylenes , acetylene dicarboxylic esters haloacetylenes , alkynyl ethers and thioethers > ynamines , fluoro-alkynes ethynyl ketpnes , nitroalkynes , etc. synthetic targets, e.g. pyrazoles , if-l,2,3-triazoles , isothiazoles , indolizines S etc. reagents, e.g. nitrones , lithium aluminium hydride , heterocyclic A -oxides - , azomethine ylids - , tertiary phosphorus compounds , miscellaneous dipolar nucleophiles - , etc. The reader will appreciate that all of these constitute alternate entries into our subject. 

The fluoro compounds could be obtained by halogen exchange reactions from the corresponding chloro compounds with zinc fluoride in diethylether The acetylene-bridged compound 17 was prepared by reaction of di(/er/-butyl)chlorosilane with sodium acetylide in THF (Eq 2). Remarkably, during such reactions gaseous acetylene was formed, so that the acetylene bridged compounds arose in a one-step synthesis. 

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