2.2- dimethyl-3-hexyne

Properties red crystals. C H NMR (benzene- / ) 8(carbyne Q) = 304.6 ppm. Re N(2,6-C6H3-f Pr) (CCMe3) OCMe(CF3)2 2 reacts with 3-hexyne to give a rhenacyclobutadiene derivative. 2,2-Dimethyl-3-hexyne is lost rapidly from the initially formed a-/cr/-butyl-substituted metallacycles. 

Property Dimethyl-hexyned Dimethyl-octyn Tetramethyl-decynedi ... 

Property Dimethyl-hexyned iol Dimethyl- octyn ediol Tetramethyl-decynedi ol... 

The carbonylation of 2-methyl-3-butyn-2-oI (50) in benzene gives teraconic anhydride (51). Fulgide (53) (a dimethylenesuccinic anhydride derivative), which is a photochromic compound, can be prepared by the carbonylation of 2,5-dimethyl-3-hexyne-2,5-diol (52)[21], The reaction proceeds under milder conditions when PdlOAc) is used as a catalyst in the presence of iodine [23],... 

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). 

Q -D-ido-Hexopyranoso[6,5,4-de][l,3]oxa2ine, 4,6-dideoxy-5, 6 -dihydro-nomenclature, 1, 31 3-Hexyne, 2,2,5,5-dimethyl-oxidation... 

DIMETHYL-2,5-DI(tert-BUTYLPEROXY)HEXYNE-3, technical pure 2158 1068-27-5... 

Hydrogenation of 2,5-diacetoxy-2,5-dimethyl-3-hexyne 10 over 0% palladium-on-carbon is exceptionally complex. Seven different products are formed together with acetic acid. All are hydrogenolysis products arising from the initially formed 2,5-diacetoxy-2,5-dimethyl-3-hexene 11. One of these, 2,5-dimethyl-2-acetoxy-4-hexene 12 forms in as much as 4S yield. 

Hexyne, 2-hexyne, 3-hexyne, 3-methyl-Hpentyne, 4-methyl-l-pentynep 4-methyl-2-pentyne, 3.3-dimethyl-l-butyne... 

The inherent plane of chirality in the metal carbene-modified cyclophane 45 was also tested in the benzannulation reaction as a source for stereoselectivity [48]. The racemic pentacarbonyl(4-[2.2]metacyclophanyl(methoxy)carbene)-chromium 45 reacts with 3,3-dimethyl-1-butyne to give a single diastereomer of naphthalenophane complex 46 in 50% yield the sterically less demanding 3-hexyne affords a 2 1 mixture of two diastereomers (Scheme 30). These moderate diastereomeric ratios indicate that [2.2]metacyclophanes do not serve as efficient chiral tools in the benzannulation reaction. 

The acyclic octamethyltetradecapentayne 36 was constructed either from chlorotetrayne 21 by adding one dimethylethynyl unit or starting from 2,5-dich-loro-2,5-dimethyl-3-hexyne (37) by coupling with one ethynyl unit on either side (Scheme 8) [4]. 

Yong et al. developed a cobalt-catalyzed [2+2+2] cyclotrimerization of terminal alkynes in good yields in aqueous media (80/20 mixture of water and ethanol) at room temperature. A cyclopentadienyl cobalt complex bearing a pendant phosphine ligand was used as a catalyst (Eq. 4.59). The cyclotrimerization of internal alkynes resulted in lower yields and required an elevated temperature, most likely due to steric interactions. For example, cyclotrimerization of 2,5-dimethyl-3-hexyne gave hexaisopropylbenzene in 51% yield and the reaction of diphenylethyne resulted in a 47% yield of hexaphenylbenzene.112... 

The effect of solvents on the kinetics of addition to hexyne-1 was studied (56) with Et3SiH. Solvents with dielectric constants from 1.6 to 20.7 had scarcely any measureable effects on the rates of addition. Electron-donating solvents such as pyridine or dimethyl sulfoxide even in very small amounts stopped the reaction entirely. 

SYNTHESIS AND UTILIZATION OF INDIUM (I) IODIDE FOR IN SITU FORMATION OF ENANTIOENRICHED ALLENYLINDIUM REAGENTS AND THEIR ADDITION TO ALDEHYDES (2R,3S,4S)-1-(tert-BUTYLDIPHENYLSILYLOXY)-2,4-DIMETHYL-5-HEXYN-3-OL [5-Hexyn-3-ol, 1-[[(1,1-dimethylethyl)diphenylsilyl]oxy]-2,4-dimethyl-,... 

Studying the action of sulfur on hydrocarbons, Teste and Lozach - showed that sulfur and PjSj with 2,5-dimethyl-3-hexyne-2,5-diol resulted in the formation of 2,5-diraethylthieno[3,2-6]thiophene (19) (R = Me, R = H) in very low yields, while with 3,6-dimethyl-oct-4-yne-3,6-diol they gave 2,3,5,6-tetramethylthieno[3,2-Z>]thiophene (19) (R = R = Me) [Eq. (4)]. 

From the difference between the enthalpies of formation of 2,5-dimethyl-2,5-dihydroperoxyhexane and 2,5-dimethyl-2,5-dihydroperoxyhex-3-yne, the enthalpies of hydrogenation of the alkyne are derived as —298.5 kJmol (g) and —309.6 kJmol (s). The gas phase value is quite a bit larger than that for its deoxygenated counterpart, 3-hexyne, of —272.4 kJmol (g) - However, the calculated solid phase enthalpy of hydrogenation of 2,5-dimethylhex-3-yn-2,5-dior to 2,5-dimethylhexane-2,5-diol is -295.7 kJmor. ... 

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