Tert-Butylacetylene

To a mixture of 0.40 mol of neohexene ( commercially available) and 200 ml of dry diethyl ether 0.35 mol of bromine was added with cooling between -40 and -50°C. The diethyl ether and excess of neohexene were then completely removed by evaporation in a water-pump vacuum.In the second flask was placed a solution of 90 g of commercial KO-tert.-C9H9 (see Chapter IV, Exp. 4, note 2) in 250 ml of DMSO. The dibromo compound was added in five portions during 15 min from the dropping funnel after the addition of each portion the flask was swirled gently in order to effect homogenization. Much heat was evolved and part of the tert.-butylacetylene passed over. After the addition the flask was heated for 30 min in a bath at B0-100°C. 

Most of these catalytic systems are able to dimerize either aromatic alkynes, such as phenylacetylene derivatives, or aliphatic alkynes, such as trimethylsilylacetylene, tert-butylacetylene and benzylacetylene. The stereochemistry of the resulting enynes depends strongly on both the alkyne and the catalyst precursor. It is noteworthy that the vinylidene ruthenium complex RuCl(Cp )(PPh3)(=C=CHPh) catalyzes the dimerization of phenylacetylene and methylpropiolate with high stereoselectivity towards the ( )-enyne [65, 66], and that head-to-tail dimerization is scarcely favored with this catalyst. It was also shovm that the metathesis catalyst RuCl2(P-Cy3)2(=CHPh) reacted in refiuxing toluene with phenylacetylene to produce a... 

The ethyl group in complex 177 can easily be substituted by an acetone ligand, via the tetrahedral intermediate 178, leading to the formation of the dimeric compound 179. The initial compound 177 can also react with tert-butylacetylene. The reaction with 1 equiv of tert-butylacetylene involves / -H transfer and results in the formation of product 180. The treatment of this vinylic compound with an excess of v/-butylacctylcnc leads to the formation of products 181 and 182 (Scheme 6) <1999JA11605>. 

An unexpected displacement of di-tert-butylacetylene was observed on heating of complex 83 to 50 °C in the presence of trimethylphosphane. The new triphosphete complex 85 was isolated as yellow needles in 55% yield. The mechanism of formation of compound 85 included a retro Diels-Alder reaction (Scheme 7) <1997CB1491>. 

General methods for the direct conversion of terminal alkynes (i.e. without silyl or stannyl activation) to alkynyliodonium triflates have not been described. The preparation of (tert-butylethynyl)phenyliodonium triflate from tert-butylacetylene with a 1 1 molar mixture of iodosylbenzene and triflic acid [PhlO-TfOH] has been reported78, but with other terminal alkynes, this procedure affords /l-(trifluoromethanesulfonyloxyvinyl)-iodonium triflates78. 

In addition to 38 and 39, other similar i74-l,3-diphosphacyclobutadiene complexes have been made with iron, rhodium, and iridium (40). Interesting chemistry is observed with rhodium, where two of the molecules appear to have dimerized with a metathetical extrusion of di-tert-butylacetylene to give a sandwich complex with the two rhodium atoms complexing on opposite sides of a twisted 1,2,4,5-tetraphosphacyclo-hexatriene ring (40). 

Reaction of Sulfur Trioxide with Perfluoro-tert-butylacetylene... 

What is the structure of the product of the reaction of sulfur trioxide with perfluoro-tert-butylacetylene ... 

Later a more convenient synthesis of 172 appeared heating di-tert-butylacetylene with elemental sulfur in benzene at 190°C in an autoclave... 

Treatment of 133 or di-tert-butylacetylene with zirconocene and then with SC12 afforded dithietes 134 and 172, respectively (92TH1). The di-... 

According to the procedure described in a patent [S. Nakagawa, A. Asai, S. Kuroyanagi, M. Ishihara, Y. Tanaka, US Patent 5 231 183 (1993), to Banyu Pharmaceutical Co.] the final step in the synthesis is carried out by reacting ii-N-(3-chloroprop-2-enyl)-N-methyl-l-naphthalenemethanamine with tert-butylacetylene at 20°C under the conditions shown in Equation 17. 

Catalysts of the second type are equimolar mixtures of MoCls or WC16 with an organometallic cocatalyst. These catalysts polymerize not only monosubstituted but also disubstituted acetylenes. This is exemplified by the polymerization of C6 alkynes (see Table 5) Ziegler catalysts can polymerize only primary or secondary monoalkylacetylenes, MoCl5 and WClg polymerize tert-butylacetylene as well, and... 

In Table 19 are collected typical monomers that polymerize with group 5 and 6 transition metal catalysts to produce high-molecular-weight (Mw > 1 x 10s) polyacetylenes. Among them, tert-butylacetylene and 3-(trimethylsilyl)-l-octyne are monosubstituted acetylenes, while the others are disubstituted ones. It is noteworthy that all of these monomers are considerably sterically crowded. By judicious choice of polymerization conditions, the polymer yield becomes fair to quantitative in every case. The Rtw s of the polymers reach ca. 3 x 10s 2 x 106. 

The kind of useful polymerization solvents depends on the reactivity of monomers. tert-Butylacetylene polymerizes not only in oxygen-containing solvents (1,4-dioxane, anisole, methyl benzoate, acetophenone, etc.) but also in nitrogen-containing solvents (benzonitrile, acetonitrile, nitrobenzene, nitroethane, etc.)19). Therefore, it can be said that tm-butylacetylene is one of the most reactive monomers in the polymeriza-... 

Katz and Lee showed that isolated metal carbenes, 3 a and 3b, induce acetylenes such as tert-butylacetylene to polymerize (Eq. (10))9). It is known that olefin metathesis is also catalyzed by these metal carbenes 75,76). These facts strongly suggest... 

Together with di-tert-butylacetylene and 3-/ert-butylprop-2-ynoate. 

Clusters 19 22 and 24 have also been tested as catalyst precursors for the hydrogenation of diphenylacetylene (Table 1, entries 16, 18, 20). Z-Stilbene (kinetic product) and f-stilbene (thermodynamic product) are formed with higher conversions (70-100% after 90 min) than in the case of terminal alkynes. As with tert-butylacetylene, similar activities and selectivities are observed for the five cluster complexes, suggesting the intermediacy of common catalytic species in solution. Compound 27 (which arises from the reactions of 21 or 22 with diphenylacetylene) and compound 28 (which arises from the reaction of 24 with the same alkyne) (Fig. 4) have been proposed as catalytic intermediates in these hydrogenation reactions. ... 

The spectra in figure 4.16 show that a single atom substitution may have an enormous effect on the intramolecular dynamics, since there is a remarkable difference in the rotationally resolved spectra of the fundamental and first overtone of these two molecules. The line width of the silicon-substituted compound is significantly narrower than that of tert-butylacetylene in both the fundamental and first overtone. There is also a striking different behavior of the two molecules in going from fundamental to overtone excitation. Tert-butylacetylene shows a decreased IVR lifetime in the overtone, dropping by almost a factor of 2. In contrast, the silicon substituted compound shows exactly the opposite behavior since the lifetime in the fundamental is decreased by almost a factor of 2 compared to the overtone. 

Kriierke and Hiibel (57) reported the isolation of some very complex products from the reaction of either tert-butylacetylene or phenylacetylene with mercury bis(cobait tetracarbonyl). In each case one product analyzed correctly for Co4Hg2(CO)i2[RC2H]2 (XCI) and the one where R=Ph disproportionated easily to give bis(cobalt tetracarbonyl)mercury and new... 

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