Allyl benzene

Similar to the formation of allylmagnesium chloride (25), the oxidative addition of allyl halides to transition metal complexes generates allylmetal complexes 26. However, in the latter case, a 7i-bond is formed by the donation of 7i-electrons of the double bond, and resonance of the n-allvl and 7i-allyl bonds in 26 generates the 7i-allyl complex 27 or (/ -allyl complex. The carbon-carbon bond in the 7i-allyl complexes has the same distance as that in benzene. Allyl Grignard reagent 25 is prepared by the reaction of allyl halide with Mg metal. However, the 7i-allyl complexes of transition metals are prepared by the oxidative addition of not only allylic halides, but also esters of allylic alcohols (carboxylates, carbonates, phosphates), allyl aryl ethers and allyl nitro compounds. Typically, the 7i-allylpalladium complex 28 is formed by the oxidative addition of allyl acetate to Pd(0) complex. 

Is Delocalization a Driving Force in Chemistry Benzene, Allyl Radical, Cyclobutadiene and their Isoelectronic Species. 

S. S. Shaik, P. C. Hiberty, J.-M. Lefour, G. Ohanessian, J. Am. Chem. Soc. 109, 363 (1987). Is Delocalization a Driving Force in Chemistry Benzene, Allyl Radical, Cyclobutadiene and their Isoelectronic Species. 

Isoamyl acetate Heptane Dioxane Benzene Allyl alcohol... 

The a—71 partition scheme under constant nn by means of eqs 34-36 has been used in a straightforward way to study the distortive properties of the TT-electronic system in the ground states of benzene, allyl radical, and cyclobutadiene and in a number of isoelectronic molecules bearing hetero-atoms. The typical results for allyl radical and benzene at different computational levels are shown in Table 1. 

Here Eg and Ex correspond to eqs 34 and 35. When the total nuclear repulsion energy Ain was kept constant, they found in all three cases that Eg is raised and Ex is lowered upon distortion. The 0 framework was found to be responsible for the C v symmetry of these structures. In a more comprehensive study of this question. Gobbi et al." commented on the role of o and n stabilization in benzene, allyl cation, and allyl anion. Their analysis was based on the first and second derivatives of the SCF canonical orbital energies with respect to normal coordinates Q. Since those energy derivatives show the behavior of the 0 and ji orbitals with respect to the deformation along each normal coordinate, the results indicate whether the orbital is stable or unstable toward... 

The Role of a and Tt Stabilization in Benzene, Allyl Cation and Allyl Anion. A Canonical Orbital Energy Derivative Study. 

A white solid, m.p. 178 C. Primarily of interest as a brominaling agent which will replace activated hydrogen atoms in benzylic or allylic positions, and also those on a carbon atom a to a carbonyl group. Activating influences can produce nuclear substitution in a benzene ring and certain heterocyclic compounds also used in the oxidation of secondary alcohols to ketones. 

Molecules 1,4-CHDN 1,3-CHDN BCE benzene -I- H2 BCE/allyl biradical... 

Cs subgroup which was used above in the allyl ease) has no degenerate representations. Moleeules with higher symmetry sueh as NH3, CH4, and benzene have energetieally degenerate orbitals beeause their moleeular point groups have degenerate representations. 

Aside of benzene the chemist has a choice in which allyl she can use. Allyl alcohol, allyl bromide or allyl chloride can be used with equal success but allyl alcohol is a nice bonus because it is easier... 

There is one other benzene to allylbenzene method that you should take a look at. Osmium sent in the article in which that magical clay and other similar catalyst add the allyl to aryl in record fashion. To read more check out ref 143. 

Indene derivatives 264a and 264b are formed by the intramolecular reaction of 3-methyl-3-phenyl-l-butene (263a) and 3,3,3-triphenylpropylene (263b) [237]. Two phenyl groups are introduced into the /3-substituted -methylstyrene 265 to form the /3-substituted /3-diphenylmethylstyrene 267 via 266 in one step[238]. Allyl acetate reacts with benzene to give 3-phenylcinnamaldehyde (269) by acyl—O bond fission. The primary product 268 was obtained in a trace amount[239]. 

Benzoic acid and naphthoic acid are formed by the oxidative carbonylation by use of Pd(OAc)2 in AcOH. t-Bu02H and allyl chloride are used as reoxidants. Addition of phenanthroline gives a favorable effect[360], Furan and thiophene are also carbonylated selectively at the 2-position[361,362]. fndole-3-carboxylic acid is prepared by the carboxylation of 1-acetylindole using Pd(OAc)2 and peroxodisulfate (Na2S208)[362aj. Benzoic acid derivatives are obtained by the reaction of benzene derivatives with sodium palladium mal-onate in refluxing AcOH[363]. 

Diphenylketene (253) reacts with allyl carbonate or acetate to give the a-allylated ester 255 at 0 °C in DMF, The reaction proceeds via the intermediate 254 formed by the insertion of the C = C bond of the ketene into 7r-allylpalla-dium, followed by reductive elimination. Depending on the reaction conditions, the decarbonylation and elimination of h-hydrogen take place in benzene at 25 °C to afford the conjugated diene 256(155]. 

Dimerization is the main path. However, trimerization to form 1.3,6,10-dodecatetraene (15) takes place with certain Pd complexes in the absence of a phosphine ligand. The reaction in benzene at 50 C using 7r-allylpalladium acetate as a catalyst yielded 1,3,6,10-dodecatetraene (15) with a selectivity of 79% at a conversion of 30% based on butadiene in 22 h[ 19,20]. 1,3,7-Octatriene (7) is dimerized to 1,5,7,10.15-hexadecapentaene (16) with 70% selectivity by using bis-rr-allylpalladium. On the other hand. 9-allyl-l,4,6.12-tridecatetraene (17) is formed as the main product when PI13P is added in a 1 1. ratio[21]. 

A 20% excess of ethylmagnesium bromide was prepared from magnesium (6.5 g) in ether (80 ml) by adding ethyl bromide (30 g) in ether (30 ml). Indole (25.8 g) in benzene (50 ml) was then added slowly with stirring and stirring was continued for 20 min after addition was complete. A solution of allyl bromide (29.2 g) in benzene (20 ml) was then added slowly. The mixture was stirred overnight and then diluted with ether and the product isolated and purified by distillation (22.7 g, 70% yield). 

Most of the resonance stabilization of benzene is lost when it is converted to the cyclohexadienyl cation intermediate In spite of being allylic a cyclohexadienyl cation IS not aromatic and possesses only a fraction of the resonance stabilization of benzene... 

C 1 IS more reactive because the intermediate formed by electrophilic attack there IS a relatively stable carbocation A benzene type pattern of bonds is retained m one nng and the positive charge is delocalized by allylic resonance... 

A heterocyclic ring induces partial double-bond fixation in a fused benzene ring. Hence, for example, diazo coupling occurs at the 7-position of 6-hydroxyindazole (349), and Claisen rearrangement of 6-allyloxy-2-methylbenzothiazole (350) gives the 7- and 5-allyl products in a ratio of 20 1. 

Allyl alcohol, TsOH, benzene, — H20. These conditions were used to pre-... 

The checkers found this distillation to require about 15 hours. The distillate is the ternary azeotrope. It consists of 8.5% water, 9.2% allyl alcohol, and 82.2% benzene, and boils at 68.2°. The aqueous layer contains some allyl alcohol, though this loss is insignificant, since only about 15 ml. of the aqueous layer is obtained from each mole of lactic acid used. 

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