P-Toluenesulfonate, leaving group

All these reactions of octadecyl p toluenesulfonate have been reported in the chemical literature and all proceed in synthetically useful yield You should begin by identifying the nucleophile in each of the parts to this problem The nucleophile replaces the p toluenesulfonate leaving group in an Sn2 reaction In part (a) the nucleophile is acetate ion and the product of nucleophilic substitution IS octadecyl acetate... 

Displacement of the p-toluenesulfonate leaving group by sodium azide in an 8 2 process and proceeds with inversion of configuration. 

Section 8 14 Nucleophilic substitution can occur with leaving groups other than halide Alkyl p toluenesulfonates (tosylates) which are prepared from alcohols by reaction with p toulenesulfonyl chloride are often used... 

In Its ability to act as a leaving group p toluenesulfonate is even more reactive than iodide... 

Because halides are poorer leaving groups than p-toluenesulfonate, alkyl p-toluene-sulfonates can be converted to alkyl halides by Sn2 reactions involving chloride, bromide, or iodide as the nucleophile. 

The reaction of benzenesulfonic acid with sodium hydroxide (first entry in Table 24.3) proceeds by the addition-elimination mechanism of nucleophilic aromatic substitution (Section 23.6). Hydroxide replaces sulfite ion (S03 ) at the carbon atom that bear s the leaving group. Thus, p-toluenesulfonic acid is converted exclusively to p-cresol by an analogous reaction ... 

The formation of 69 suggests that even the p-toluenesulfonate ion can undergo the regioselective nucleophilic attack at the 5 position, as the 1-hydroxy leaving group departs from 39 upon protonation. 

Tosylate (Section 11.1) A p-toluenesulfonate ester useful as a leaving group in nucleophilic substitution reactions. 

In contrast to phosphorus esters, sulfur esters are usually cleaved at the carbon-oxygen bond with carbon-fluorine bond formation Cleavage of esters of methanesulfomc acid, p-toluenesulfonic acid, and especially trifluoromethane-sulfonic acid (triflic acid) by fluoride ion is the most widely used method for the conversion of hydroxy compounds to fluoro derivatives Potassium fluoride, triethylamine trihydrofluoride, and tetrabutylammonium fluoride are common sources of the fluoride ion For the cleavage of a variety of alkyl mesylates and tosylates with potassium fluoride, polyethylene glycol 400 is a solvent of choice, the yields are limited by solvolysis of the leaving group by the solvent, but this phenomenon is controlled by bulky substituents, either in the sulfonic acid part or in the alcohol part of the ester [42] (equation 29)... 

TosOH 4-methylbenzenesulfonic acid = p-toluenesulfonic acid, tosic acid" X, Y leaving groups, e.g., halogen, RSO, in substitution and elimination reactions... 

The hydroxyl group must be replaced by azide with inversion of configuration. First, however, a leaving group must be introduced, and it must be introduced in such a way that the configuration at the stereogenic center is not altered. The best way to do this is to convert (R)-sec-butyl alcohol to its corresponding p-toluenesulfonate ester. 

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