Sulfonations methanesulfonic anhydride

In a few cases the electrophilic Frledel-Craft type acylation can be used for the one step synthesis of aryl methyl sulfones, as exemplified by the reaction of DDE with methanesulfonic anhydride (226). 

Aryl methyl sulfones can be obtained in average yields of 60% by heating aromatic hydrocarbons with methanesulfonic anhydride 230... 

In 1996, Mitsubishi Chemical Corporation discovered that chain sulfonic acid anhydrides, such as methanesulfonic anhydride (49), can be used as additives in small quantities [77]. Furthermore, in 2002, NEC Corporation found that the cyclic sulfonic anhydride 1,2-ethanedisulfonic anhydride (50) can be used as an additive in small quantities [78]. 

Sulfone Formation. Friedel-Crafts methylsulfonation of benzene or substituted benzenes can be achieved via treatment with methanesulfonic anhydride in the presence of a Lewis acid catalyst (eqs 5 and 6). Unlike methanesulfonyl chloride, which sulfonates only activated benzenes, treatment of deactivated benzenes with methanesulfonic anhydride produces the desired sul-fones in good yields. Diaryl sulfones can be formed using methanesulfonic anhydride and sulfuric acid (eq 7). ... 

Sulfonate Formation. The preparation of an alkyl methane-sulfonate from an alcohol can be achieved by treatment of an alcohol with methanesulfonic anhydride in the presence of pyridine or 2,4,6-collidine (eq 1). The use of methanesulfonic anhydride rather than methanesulfonyl chloride eliminates the formation of small amounts of alkyl chlorides which occurs when... 

The third procedure illustrated by this preparation involves the reaotion of ketones with trifluoromethanesulfonic anhydride in a solvent such as pentane, methylene chloride, or carbon tetrachloride and in the presence of a base such as pyridine, lutidine, or anhydrous sodium carbonate.7-11,15 This procedure, which presumably involves either acid-catalyzed or base-catalyzed enolization of the ketone followed by acylation of the enol with the acid anhydride, has also been used to prepare other vinyl sulfonate esters such as tosylates12 or methanesulfonates.13... 

Conversion of alcohols to sulfonate esters is a way of labilising them to nucleophilic substitution and elimination. The common leaving groups are arenesulfonates, particularly p-toluenesulfonate (tosylate), methanesulfonates (mesylate) and trifluromethanesulfonate (triflate) they are introduced by reaction of the acid chlorides (or, in the case of the trifluoromethanesulfonates, acid anhydrides) in a basic solvent such as pyridine. Traditionally, the reactions are carried out in pyridine as solvent, but both this solvent and the liberated... 

The desired sulfonate ester is usually prepared by reaction of the alcohol in pyridine with the appropriate sulfonyl chloride, that is, methanesulfonyl chloride (mesyl chloride) for a mesylate, y)-toluenesulfonyl chloride (tosyl chloride) for a tosylate, or trifluoromethane-sulfonyl chloride [or trifluoromethanesulfonic anhydride (triflic anhydride)] for a triflate. Pyridine (C5H5N, pyr) serves as the solvent and to neutralize the HCI formed. Ethanol, for example, reacts with methanesulfonyl chloride to form ethyl methanesulfonate and with yj-toluenesulfonyl chloride to form ethyl /-toluenesulfonate ... 

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