L-Hexyn

Eig. 7. CycHc voltammograms for the reduction of 1.0 mAf [2,2 -ethylene-bis(nitrilomethyHdyne)diphenolato]nickel(II) in dimethyl formamide at a glassy carbon electrode, in A, the absence, and B and C the presence of 2.0 and 5.0 mAf 6-iodo-l-phenyl-l-hexyne, respectively (14). 

In the presence of 6-iodo-l-phenyl-l-hexyne, the current increases in the cathodic (negative potential going) direction because the hexyne catalyticaHy regenerates the nickel(II) complex. The absence of the nickel(I) complex precludes an anodic wave upon reversal of the sweep direction there is nothing to reduce. If the catalytic process were slow enough it would be possible to recover the anodic wave by increasing the sweep rate to a value so fast that the reduced species (the nickel(I) complex) would be reoxidized before it could react with the hexyne. A quantitative treatment of the data, collected at several sweep rates, could then be used to calculate the rate constant for the catalytic reaction at the electrode surface. Such rate constants may be substantially different from those measured in the bulk of the solution. The chemical and electrochemical reactions involved are... 

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)... 

The alkane formed by hydrogenation of (S)-4-methyl-l-hexyne is optically active, but the one formed by hydrogenation of (S)-3-methyl-l-pentyne is not. Explain. Would you expect the products of hydrogenation of these two compounds in the presence of Lindlar palladium to be optically active ... 

Acetylenic compounds have been described for inhibition in acid solutionsTypical inhibitors include 2-butyne-l,4-diol, l-hexyne-3-ol and 4-ethyl-l-octyne-3-ol. 

Ethylenedioxybutyl)-3-trichloro-acetamido-l-cyclohexene, 58, 9, 11 Ethylene glycol, 56, 44 Ethyl a-fluoro-l-naphthaleneacetate, 57, 73 Ethyl 2-fluoropropanoate, 57, 73 3-Ethylhexane, 58, 3, 4 3-ETHYL-l-HEXYNE, 58, 1, 2, 3, 4 Ethylidenecyclohexane, 59, 46 Ethyliodide, 59, 133 Ethyl 2-iodo-3-nitropropionate, 56,65 Ethyl isocyanide, 55, 98 Ethyl isocyanoacetate, 59,184 l-Ethyl-4-isopropylbenzene, 55,10 Ethyl levulinates, 5-substituted, 58, 81 ETHYL 2-METHYL1NDOLE-5CARBOXY-LATE, 56, 72... 

Dipolar cycloaddition reaction of trimethylstannylacetylene with nitrile oxides yielded 3-substituted 5-(trimethylstannyl)isoxazoles 221. Similar reactions of (trimethylstannyl)phenylacetylene, l-(trimethylstannyl)-l-hexyne, and bis (trimethylsilyl)acetylene give the corresponding 3,5-disubstituted 4-(trimethyl-stannyl)isoxazoles 222, almost regioselectively (379). The 1,3-dipolar cycloaddition reaction of bis(tributylstannyl)acetylene with acetonitrile oxide, followed by treatment with aqueous ammonia in ethanol in a sealed tube, gives 3-methyl-4-(tributylstannyl)isoxazole 223. The palladium catalyzed cross coupling reaction of... 

Hexyllithium, 15 147 Hexyl methyl carbonate molecular formula, 6 305t l-Hexyn-3-ol, l 249t 5-Hexynoic acid, 5 34t Hexynol... 

The /3-trimethyltin-substituted alkenylborane 36 was prepared in situ by treatment of triethylborane with 1-lithio-l-hexyne to form the lithium 1-alkynyltriethyl-borate 35 followed by trimethyltin chloride (Scheme 20.9) [37]. The trimethyltin chloride-induced migration of an ethyl group from boron to the adjacent acetylenic carbon is stereoselective with the boron and the tin substituents in 36 cis to each... 

Several publications deal with acetylenic halides that can undergo reductive intramolecular cyclization [37]. For example, electrolysis of 6-iodo-l-phenyl-l-hexyne at a carbon cathode gives benzylidenecy-clopentane in 36% yield. 

Better results can be obtained by generating the boronate species with the aid of sodium methoxide. In this case, satisfactory transmetalation occurs on treatment with Cul. Thus, the functionalized copper reagent 55 can be alkynylated with 1-bromo-l-hexyne at —40 °C, furnishing the enyne 56 in 75% yield (Scheme 2.15) [32]. 

The stereospecific construction of the trisubstituted double bond of the side chain at C-1 of carbazomadurins A (253) and B (254) was achieved using Negishi s zirconium-catalyzed carboalumination of alkynes 758 and 763, respectively. Reaction of 5-methyl-l-hexyne (758) with trimethylalane in the presence of zirconocene dichloride, followed by the addition of iodine, afforded the vinyl iodide 759 with the desired E-configuration of the double bond. Halogen-metal exchange with ferf-butyllithium, and reaction of the intermediate vinyllithium compound with tributyltin chloride, provided the vinylstannane 751a (603) (Scheme 5.79). 

Although this alkylation of alkali chloroacetylide is completely analogous to the alkylations described in the previous experiments, the procedure for the preparation of 1-chloro-l-hexyne warrants a brief explanation. 

Diethylamino-l-hexyne from the Corresponding Tosyiate and Diethylamine... 

Presence of a certain type of functional groups in alkynes does not interfere with silylformylation. For example, the chlorine atom in 5-chloro-l-pentyne 44 and the cyano group in 5-cyano-l-pentyne 46 do not affect the silylformylation to give 45 and 47 respectively (Equations (10) and (11)). 4-Bromo-l-butyne and 6-bromo-l-hexyne also give the corresponding silylformylation products." ... 

To a large bottle are added 116.5 gm (1.0 mole) of 3-chloro-l-hexyne, 20.0 gm (0.20 mole) of cuprous chloride, 16.0 gm (0.30 mole) of ammonium chloride, 10 ml of concentrated hydrochloric acid, 50 ml of water, and 0.6 gm of copper bronze. The bottle is sealed and shaken at room temperature for 14 days. The organic layer is separated, dried over potassium carbonate, and fractionally distilled through a glass-helix-packed column to afford 61.0 gm (52%) of nearly pure l-chloro-l,2-hexadiene, b.p. 54°-57°C (50 mm), p5 1.4567-1.4680, 9.3 gm (8%) of 3-chloro-l-hexyne, and some polymeric material. Shorter periods of reaction give lower yields. The product is purified as described for bromopropadiene. 

An independent proof of this finding was recently obtained by Ciardelli, Benedetti, Pieroni and Pino (23, 24) who prepared an atactic poly-(S)-4-xnethyl-1-hexene having [M] >5 = +190 from a poly-(S)-4-methyl-l-hexyne having an optical purity of about 89.5% as demonstrated by the optical purity of (S)-3-methyl-pentanoic acid obtained by ozonization of the unsaturated polymer. The rotatory power of the polymer thus prepared is very near to the rotatory power of the non crystallizable poly-(S)-4-methyl-l-hexene obtained from a monomer having a 93% optical purity (see Table 8). 

I. R. spectra of polymers of optically active and racemic monomers (12) having similar stereoregularity are identical in the case of poly-5-methyl-l-heptene, but slightly different in the case of poly-3-methyl-l-pentene and poly-4-methyl- 1-hexene. A very characteristic crystallinity band has been found in the I. R. spectrum of poly-5-methyl-l-heptene at 12.06 fi bands which seem connected with stereoregularity have been found in the I. R, spectrum of poly-4-methyl-l-hexene at 10.06 fi the nature of these bands has been proved when preparing a practically atactic sample by hydrogenation of poly-4-methyl-l-hexyne (24). 

FLUORINECOMPOUNDS,ORGANIC - FLUORINATED AROMATIC COMPOUNDS] (Vol 11) 6-Iodo-l-phenyl-l-hexyne... 

Whereas a number of 5-aryl thiatriazoles have been reported, the only previously known true aliphatic and alicyclic representatives were 5-tert-butyl31 and cyclohexyl thiatriazole.32 These are unstable oils that decompose at 0° with nitrogen evolution and formation of sulfur. They are prepared from the corresponding thioacylhydrazides and nitrous acid, but the method is not generally applicable because of difficulties in obtaining the required aliphatic thioacylhydrazides.1 Wijers et o/.17 have found that aliphatic thiatriazoles can be prepared from 1-acetylthio-l-alkynes. Thus a substance believed to be 5-pentylthiatriazole was isolated from the reaction between 1-acetylthio-l-hexyne and ammonium azide. It is an oil that solidifies at about —16° and could not be analyzed because of its explosive character and poor stability at room temperature. Its formation is explained by the following scheme [Eq. 

In a similar manner, the reaction of 5-dimethylsilyl-l-hexyne (111) catalyzed by H2PtCl6 affords 5-exo-dig cyclization product 112 exclusively (equation 47)130. 

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