1-phenyl-l-propyne

Figure 1. Reaction profile for 1-phenyl-l-propyne hydrogenation.

The reaction of 1-phenyl-l-propyne (IPP) was then studied after modilying the catalyst with trans-cinnamaldehyde (TCA), trans-cinnamonitrile (TCN), 3-phenylpropionitrile (3PPN), and 3-phenylpropylamine (3PPA). The first-order rate constant calculated for the loss of 1-phenyl-l-propyne in each of the systems is reported in Table 1. All the modifiers were unreactive under the conditions used. 

Table 1. First-order rate constants (min ) for the hydrogenation of 1-phenyl-l-propyne in the presence of modifiers.

The mechanism of the Au(III) catalysis proposed in Scheme 5 implies the stereoselective formation of the new C-C bond which, of course, cannot be observed in the final product when terminal alkynes are used (the aryl group and the former alkyne hydrogen are situated at the same side of the double bond in the vinyl-Au intermediate). For the reaction of 1-phenyl-l-propyne and mesitylene 1 (see below, Table 1) the proposed mechanism should lead to preferential formation of the Z isomer which is, in fact, observed [2]. The formation of a small amount of E isomers can be explained by isomerization of the initially formed Z compound. Such isomerization was, in fact, observed directly in the case of related electron-poor alkynes [4],... 

Phenyl-1-alkynes (1-phenyl-l-propyne, -1-butyne, and -1-nonyne) polymerize in high yields in the presence of WClg—Pl Sn 30,32). The Mw s of the polymers, however, are not very high (5x 103-5x 104). MoCls—Ph4Sn is virtually inactive toward these acetylenes. 

Fig. 1. Time dependences of monomer conversion and polymer MW in the polymerization of 1-phenyl-l-propyne by TaCls-based catalysts in toluene, 80 °C, [Ml, = 1.0 M, [Cat] = 20 mM 57)...

A catalyst solution is prepared by mixing TaCl5 (0.20 mmol, 72 mg) and -Bu4Sn (0.20 mmol, 69 mg) in toluene (5.0 ml), and aged by keeping at 80 °C for 15 min. To this solution is added a mixture of 1-phenyl-l-propyne (10 mmol, 1.2 g, 1.3 ml) and toluene (3.7 ml) at 80 °C. After 24 h, polymerization is stopped. The polymer is separated by precipitation into a large amount of acetone instead of methanol, because the cyclotrimers (by-products) dissolve in acetone, but not in methanol. Polymer yield 76%, Mw 1.5 x 106. 

The interaction of hydrocarbons with the ZnO surface has been extensively studied. In particular (/) cyclopentene-ZnO interaction gives rise to mainly rr-bonded species (//) cyclobutene is adsorbed with rupture of the ring (Hi) allyl-benzene yields adsorbed phenyl-allyl species (CeHsCHCHCH ) (/V) ethynylbenzene is polymerized on the surface under the irradiation of the laser beam (v) 3-phenyl-1-propyne and 1-phenyl-l-propyne give rise... 

Example 18 Polymerization of 1-Phenyl-l-propyne with a TaOj-Based Catalyst... 

Substituted 1-halo and 1-alkoxy isoquinolines are formed from A/-methoxy benzimidoyl halides and alkynes with a ruthenium catalyst (Scheme 59) (13CC3703). The reaction with an unsymmetrical alkyne, 1-phenyl-l-propyne, occurs regioselectively, with the phenyl adding adjacent to the nitrogen. The reaction occurs with both imidoyl chlorides and... 

Dipolar cycloaddition of pyrido[2,l-A][l,3]thiazinium betaine 507 (R = Me) with 1-diethylamino-l-propyne afforded cycloadduct 508, from which quinolizin-4-one 509 formed by a rapid cheletropic extrusion of COS (Scheme 53) <1995T6651>. 1,4-Dipolar cycloaddition of 507 and 4-phenyl-l,2,4-triazoline-3,5-dione yielded 511 (via 510) <1995H(41)1631> and 512 <1995T6651>. 

The catalytic propargylic alkylation was investigated in the presence of thiolate-bridged diruthenium complexes as catalysts generated in situ from reactions of [Cp RuCl(p2-Cl)]2 with optically active thiols prepared from the corresponding optically active alcohols [27]. Typical results for the reaction of 1-phenyl-2-propyn-l-ol with acetone in the presence of a variety of catalysts are shovm in Scheme 7.19. 

Method A. To an alumina (Harshaw Chemical Co. 80 mesh alumina, slightly basic type used for chromatography is dried at 160°-170°C for 5 days before use) column (1.7 x 11 cm) is added a solution of 0.77 gm of l-(p-bi-phenyl)-3-phenyl-l-propyne in n-pentane. After 45 min the product is eluted with -pentane and concentrated at room temperature using a nitrogen atmosphere (with a water aspirator) to afford 0.53 gm (69%), m.p. 84.8°-86.4°C. 

Method B. To a pressure bottle is added a solution of 0.100 gm of 1 -(p-biphenyl)-3-phenyl-l-propyne in 50 ml of petroleum ether (b.p. 20°-40°C) with 1.0 gm of sodium hydroxide pellets. The solution is kept for 11 hr at room temperature. After this time the solution is filtered and concentrated as in Method A to afford 0.058 gm (58%) of 1 -(p-biphenyl)-3-phenylallene, m.p. 

Dipolar cycloaddition of anhydro pyrido[2,l-b][l,3]thiazinium hydroxides (128) with aryl isocyanates and dimethyl acetylenedicarboxylate gave pyrido[l,2]pyrimidines (129) and quinolizine-l,2-dicarboxylates (130), respectively (76CB3668). 1,4-Dipolar cycloaddition of pyrido[2,l-h][l,3]thi-azinium betaine (131, R = Me) with 1-diethylamino-l-propyne afforded cycloadduct 132, from which quinolizin-4-one 133 formed by a rapid cheletropic extrusion of carbonyl sulfide (93TL5405 95T6651). 1,4-Dipolar cycloaddition of anhydro 4-hydroxyl-2-oxo-6,7,8,9-tetrahydro-2//-pyrido-[2,l-b][l,3]thiazinium hydroxides (131) and 4-phenyl-l,2,4-triazoline-3,5-dione yielded 135 via 134 [94H(39)219 95H(41)1631] and 136 (95T6651). 

The BF3-induced reactions of iodosylbenzene with l-trimethylsilyl-3-aryl-l-propynes in dioxane follow a divergent course and afford aryl silylethynyl ketones (equation 28)31. The ketone derived from l-trimethylsilyl-3-phenyl-l-propyne is also generated in dichloro-methane, but as a minor product. These oxidations are apparently facilitated by the presence of benzylic hydrogen atoms, since a similar alkynyl ketone is not obtained from 1-trimethylsilyl-l-decyne with PhIO/BF3 in dioxane31. 

Intramolecular palladium-catalyzed cyclization reactions have also been used to synthesize pyrazole derivatives. iV-Aryl-iV-(o-bromobenzyl)hydrazines 494 participated in a palladium-catalyzed intramolecular amination reaction to give 2-aryl-2//-indazoles 495 (Equation 101) <20000L519>. Palladium-catalyzed intramolecular C-N bond formation of iV-acetamino-2-(2-bromo)arylindolines 496, followed by hydrolysis and air oxidation in the presence of aluminium oxide, allowed the preparation of indolo[l,2-3]indazoles 498 via intermediate 497 (Scheme 58) <2002TL3577>. 3-Substituted pyrazoles have been prepared from the intramolecular cyclization of A -tosyl-iV-(l-aryl/ vinyl-1-propyn-3-yl)hydrazine and then exposme of the reaction mixture of the cyclization to potassium /i //-butoxide <1997SL959>. iV-Aryl-iV -(o-bromobenzyl)hydrazines 499 or [A -aryl-A -(t>-bromobenzyl)hydrazinato-A ]-triphenyl-phosphonium bromides 501 participated in a palladium-catalyzed intramolecular amination reaction to give 1-phenyl-l//-indazoles 500 (Scheme 59) <2001TL2937>. 

Thus, pentacarbonylmethoxymethyl-(or phenyl-)carbenechromium, -molybdenum or -tungsten react at RT with diethylaminoethyne or 1-diethylamino-l-propyne to give, in good yields, amino-stabilized carbenes ... 

In another group of (2 + 2)-cycloaddition reactions, the heterocyclic nucleus reacts via an electron-deficient carbon-carbon or carbon-nitrogen double bond with electron-rich aminoacetylenes (ynamines). For instance, thiete 1,1-dioxides, JV-benzylmaleimide, and 2,3-bis(methoxycarbonyl)-7-oxabicyclo( 2.2.1 lhepta-2,5-diene reacted with 1-diethylamino-l-propyne and with 1 -phenyl-2-( 1 -pyrrolidinyl)-acetylene to give the (2 + 2)-cycloadducts 48, 49, and 50, respec-tively.35,37,53 The latter product was thermally rather unstable, and its structure was identified on the basis of its conversion with 2,4,6-tri-methylbenzonitrile oxide into 51.53 (2 + 2)-Cycloaddition via a carbon-nitrogen double bond has been reported to take place in the reactions of 3,3-dimethyl-3//-indoles and 3,4-dihydroisoquinoline with ynamines, e.g., l-dimethylamino-2-phenylacetylene, in the presence of boron trifluoride.54 The (2 + 2)-cycloadducts 52 and 53 were not isolated, but... 

D-Glucose orthoesters of complex alcohols can be easily obtained with the help of silver salicylate Alcohols and amines can be conveniently prepared from olefins by ozonization-reduction and ozoni-zation-reductive amination respectively without isolation of intermediates Inverted amines can be obtained from optically-active alcohols through stereospecific formation of N-alkylphthalimides 3-Methoxy-l-phenyl-l-propyne has been used as starting material for the synthesis of a,/ -unsatd. carbonyl compounds through allenic di-carbanions a-Ketocarboxylic acids can be easily prepared from cyanohydrins through a Ritter reaction... 

Many monomers with simple structures, including phenylacetylene, t-butyl-acetylene, 1-phenyl-1-propyne, 2-octyne, and 1-trimethylsilyl-l-propyne, are commercially available. These monomers are usually purified by distillation in the presence of suitable drying agents prior to use. On the other hand, monomers that are more complex, such as ort/zo-substituted phenylacetylenes, A-pro-pargylcarbamates, ring-substituted diphenylacetylenes, and 1-chloro-l-alkynes, must be synthesized. Derivatization of simple alkynes rather than formation of the acetylenic moiety, is frequently applied to synthesize such monomers. These are then purified by vacuum distillation or column chromatography. 

Table 1. Second virial coefficient of poly(l-phenyl-l-propyne).

Methoxy-l-phenyl-l-propyne in anhydrous ether added at -75° under argon to 2 moles butyllithium in the same solvent, stirred 15 min., 1 mole ethyl bromide in ether added slowly, stirred 15 min., then trimethylsilyl chloride in ether added, allowed to warm to room temp, with stirring, the soln. of the intermediate allenyl ether (Y 82% if isolated) treated with 20%-HCl, and refluxed 5 hrs. product. Y 76%. F. e. s. Y. Leroux and R. Mantione, J. Organometal. Chem. 30, 295 (1971). 

The reaction of 1-21 with alkynes is regioselective. When unsymmetrical alkynes such as 1-phenyl-1-butyne was used, l-43a and l-44a both as single regioisomers were isolated upon hydrolysis of reaction mixture at 50 °C and 90 °C respectively. The Ph group was selectively located at a-position of CpaZr moiety. The substituents on alkynes also have an effect on the chemoselectivity of the reaction. When 1-trimethylsilyl-l-propyne was used, only zirconacyclopentadiene l-43b was isolated regioselectively, and the corresponding zirconacyclohexadiene complex was not isolated (Scheme 1.21) [47, 48]. 

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