Toluenes reaction+carbonyls

Figure 13. Carbonylation of 2-iodobenzyl alcohol catalyzed by PdCljlPfOCjHslsb in scC02 and in toluene. Reaction conditions S/C = 5000, Pd cat 1,0x 10"2 M DMF solution, Pco =...

Neutral a-diketones are represented only in two crystalline quinone species MnBr2 L of unknown structure, but there is a litle more detail available on the anions of hydroxyquinones (93)-(97), the related tropolone (98) and the dianions of the cyclic carbonyls (99) for n = 2, 3 and 4. The latter give polymeric hydrates based on [MnO ] octahedra. The hydroxyquinonate anions (93)-(97) have all given crystalline species Mn(0, 0)2, one of which (97) has been shown to be tetrameric. This compound was prepared from Mn2(CO)io and the hydroxyquinone in toluene reaction in pyridine gave [Mn(0,0)2py2] 2py. The anion (94) has also b n reported to give a solid MnCl(0,0)-4Et0H. 

Stable ionic 1 1 adducts 16 are also obtained when the reaction is conducted in toluene using carbonyl isothiocyanates. Further reaction of the dipoles with phenyl isocyanate affords tetraazaspiro[4,4]nonanes 17. ... 

Cycloaddition of COj with the dimethyl-substituted methylenecyclopropane 75 proceeds smoothly above 100 °C under pressure, yielding the five-membered ring lactone 76. The regiocheraistry of this reaction is different from that of above-mentioned diphenyl-substituted methylenecyclopropanes 66 and 67[61], This allylic lactone 76 is another source of trimethylenemethane when it is treated with Pd(0) catalyst coordinated by dppe in refluxing toluene to generate 77, and its reaction with aldehydes or ketones affords the 3-methylenetetrahy-drofuran derivative 78 as expected for this intermediate. Also, the lactone 76 reacts with a, /3-unsaturated carbonyl compounds. The reaction of coumarin (79) with 76 to give the chroman-2-one derivative 80 is an example[62]. 

The reaction of alcohols with acyl chlorides is analogous to their reaction with p toluenesulfonyl chloride described earlier (Section 8 14 and Table 15 2) In those reactions a p toluene sulfonate ester was formed by displacement of chloride from the sulfonyl group by the oxygen of the alcohol Carboxylic esters arise by displacement of chlonde from a carbonyl group by the alcohol oxygen... 

Attempts have been made to develop methods for the production of aromatic isocyanates without the use of phosgene. None of these processes is currently in commercial use. Processes based on the reaction of carbon monoxide with aromatic nitro compounds have been examined extensively (23,27,76). The reductive carbonylation of 2,4-dinitrotoluene [121 -14-2] to toluene 2,4-diaLkylcarbamates is reported to occur in high yield at reaction temperatures of 140—180°C under 6900 kPa (1000 psi) of carbon monoxide. The resultant carbamate product distribution is noted to be a strong function of the alcohol used. Mitsui-Toatsu and Arco have disclosed a two-step reductive carbonylation process based on a cost effective selenium catalyst (22,23). 

When methyl 2-(indol-2-yl)acrylate derivative (22a) reacted with A-methoxy-carbonyl-l,2-dihydropyridine (8a) in refluxing toluene, in addition to the dimer of 22a (25%), a mixture of the expected isoquinculidine 23a and the product 24a (two isomers) was obtained in 7% and 45% yields, respectively (81CC37). The formation of 24a indicates the involvement of the 3,4-double bond of dihydropyridine. Similarly, Diels-Alder reaction of methyl l-methyl-2-(indol-2-yl)acrylate (22b) with 8a gave, in addition to dimer of 22b, a mixture of adducts 23b and 24b. However, in this case, product 23b was obtained as a major product in a 3 2 mixture of two isomers (with a- and (3-COOMe). The major isomer shows an a-conhguration. The yields of the dimer, 23b, and 24b were 25%, 30%, and 6%, respectively. Thus, a substituent on the nitrogen atom or at the 3-position of indole favors the formation of the isoquinuclidine adduct 23. 

Besides acylation and alkylation reactions, typical carbonyl reactions, such as reduction and substitution, are known. Thus, the oxo group in position 3 of 8 is attacked by sodium cyanide, resulting in the cyanohydrin in 55% yield. Subsequent dehydration with p-toluene-sulfonic acid and acetylation in position 5 gives 1-benzothiepin 12.90... 

The application of 1,3-dipolar cycloaddition processes to the synthesis of substituted tetrahydrofurans has been investigated, starting from epoxides and alkenes under microwave irradiation. The epoxide 85 was rapidly converted into carbonyl ylide 86 that behaved as a 1,3-dipole toward various alkenes, leading to quantitative yields of tetrahydrofuran derivatives 87 (Scheme 30). The reactions were performed in toluene within 40 min instead of 40 h under classical conditions, without significantly altering the selectivi-ties [64]. 

Few quantitative data are available on the relative nucleophilicities of L toward various alkyl carbonyls. The rates of the reaction of CpMo(CO)3Me with L in toluene (Table II) decrease as a function of the latter reactant P( -Bu)3 > P( -OBu)j > PPhj > P(OPh)j, but the spread is relatively small (<8). The above order is that customarily observed for 8 2 reactions of low-valent transition metal complexes (J, 214). Interestingly, neither CpMo(CO)3Me nor CpFe(CO)2Me reacts with 1 or N, S, and As donor ligands 28, 79). This is in direct contrast to the insertion reactions of MeMn(CO)5 which manifest much less selectivity toward various L (see Section VI,B,C,D for details). 

Purely aromatic ketones generally do not give satisfactory results pinacols and resinous products often predominate. The reduction of ketonic compounds of high molecular weight and very slight solubility is facilitated by the addition of a solvent, such as ethanol, acetic acid or dioxan, which is miscible with aqueous hydrochloric acid. With some carbonyl compounds, notably keto acids, poor yields are obtained even in the presence of ethanol, etc., and the difficulty has been ascribed to the formation of insoluble polymolecular reduction products, which coat the surface of the zinc. The adffition of a hydrocarbon solvent, such as toluene, is beneficial because it keeps most of the material out of contact with the zinc and the reduction occurs in the aqueous layer at such high dilution that polymolecular reactions are largdy inhibited (see Section IV,143). 

Water-soluble carbonyls are relatively rare. A route to such a species involves reaction at room temperature of the sulfonated phosphine P(PhS03)33- as its water-soluble Na+ salt with Co2(CO)8 in a two-phase water/toluene mixture, whereupon the product forms in the aqueous phase in high yield.85... 

The reaction of 9 (generated thermally from 7 in toluene) with tetraphenyl-cyclopentadienone is more complex. Both the [6 + 2]-cycloadduct 3416), for which an X-ray structure analysis is available, and the [12 + 2]-cycloadduct 3516), whose constitution has been assigned primarily on the basis of H-NMR evidence, are obtained. The two cycloadducts presumably have a common intermediate which, in accord with the general reactivity of 9, should possess betaine character (.31 - 32) it is caused by nucleophilic attack by the carbonyl oxygen atom on the phosphorus of the heterocumulene. Ring closure of the carbanionic carbon atom... 

In 1982, a most remarkable reaction was discovered by Bercaw et al. which involved the reductive coupling of the terminal carbonyl ligands of [CpFe(CO)2]2- When 1 equivalent of the permethylated zirconocene dinitrogen complex [(rj-CsMe Zr k (29) was treated with 2 equivalents of [CpFe(CO)2]2 in toluene above -20°C, 3 equivalents of N2 evolved... 

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