Tolyl

Figure C2.3.9. Product distribution of dissymmetrical ketone photolysis as influenced by cefyltrimethylammonium chloride (CTAC) micelles. The initial ketone, A(CO)B is photolysed to lose the carbonyl group and to produce tliree products, AA, AB and BB. These data are for benzyl (A) 4-methylbenzyl (B) ketone. Product AA is 1,2-diphenylethane, product BB is 1,2-ditolylethane and product AB is l-phenyl-2-tolyl-ethane. At low CTAC concentration, in the absence of micelles, a random distribution of products is obtained. In the presence of micelles, however, the AB product is heavily favoured. Adapted with pennission from 1571.

Many aldehydes and ketones can be reduced directly by Clenimemen s method, in which the aldehyde or ketone is boiled with dilute hydrochloric acid and amalgamated zinc. />-Methylacetophenone (or methyl />-tolyl ketone) is reduced under these conditions to />-ethyltoluene. An excess of the reducing agent is employed in order to pre ent the formation of unsaturated hydrocarbons. 

When an aqueous solution of phenyldiazonium chloride or of p-tolyl-diazonium hydrogen sulphate is treated with an equivalent of potassium iodide and warmed on a water bath, iodobenzene or />-iodotoluene is formed in good 3deld ... 

Thio-p-cresol (p-tolyl mercaptan), p-CHjCjH SH. This compound may be similarly prepared from p-toluenesulphonyl chloride (Section IV,207). The thio-p-cresol crystallises in the steam distillate and is collected and dried m.p. 43°. The b.p. under normal pressure is 194r-195°. 

Some di-p-tolyl ketone is produced as a by-product, presumably by Interaction of the lithium salt of the carboxylic acid with the aryl lithium ... 

Evaporate the dried ethereal extract the residue, m.p. 85-90°, weighs 3 3 g. Recrystallise it from alcohol pure di-p-tolyl ketone, m.p. 95°, is obtained. 

The formation of an organosodium compound (p-tolyl-sodium) is well illustrated by the interaction of sodium sand or wire with p-chlorotoluene in light petroleum (b.p. 40-60°) at about 25°, for when the reaction mixture is added to excess of solid carbon dioxide pure/ -toluic acid is obtained directly in a yield exceeding 70 per cent. ... 

In the second, a trace of toluene (possibly formed by hydrolysis) is metalated by the p-tolyl-sodium to give benzyl-sodium and toluene. Since the toluene is regenerated in the reaction, a small quantity would be adequate as a sort of catalyst. 

Pure -xylene may be prepared from p tolyl-sodium and methyl iodide or methyl sulphate. 

The cj/cioheptan9ne is readily separated by taking advantage of the experimental fact that it alone forms a soUd bisulphite compound. Diazomethane is conveniently generated in situ from p-tolyl.sulphonylmethylnltrosamlde (Section VII,20). 

R phenyl, e"-deficient aryl 30-40% R p-tolyl, e -rich aryl 10%... 

On the other hand, the halohydrin (chloro and bromo) 908 is converted into a ketone via oxidative addition and //-elimination in boiling benzene with catalysis by Pd(OAc)2 and tri(o-tolyl)phosphine in the presence of K2C03[765,766],... 

Formic acid behaves differently. The expected octadienyl formate is not formed. The reaction of butadiene carried out in formic acid and triethylamine affords 1,7-octadiene (41) as the major product and 1,6-octadiene as a minor product[41-43], Formic acid is a hydride source. It is known that the Pd hydride formed from palladium formate attacks the substituted side of tt-allylpalladium to form the terminal alkene[44] (see Section 2.8). The reductive dimerization of isoprene in formic acid in the presence of Et3N using tri(i)-tolyl)phosphine at room temperature afforded a mixture of dimers in 87% yield, which contained 71% of the head-to-tail dimers 42a and 42b. The mixture was treated with concentrated HCl to give an easily separable chloro derivative 43. By this means, a- and d-citronellol (44 and 45) were pre-pared[45]. 

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