Methanesulfonyl chloride reaction mechanism

B. cis-1,2-Gyclohexanedimethanol Dimethanesulfonate. In a 5-1., three-necked, round-bottomed flask, immersed in an ice-salt bath and fitted with a mechanical stirrer and an addition funnel, is plaeed a solution of 111 g. (0.97 mole) of methanesulfonyl chloride in 1.21. of pyridine. While cooling and stirring, a solution of 46.4 g. (0.322 mole) of m-l,2-cyclohexanedimethanol in 250 ml. of pyridine is added dropwise at a rate such that the temperature does not exceed 0° (Note 5). Upon completion of the addition, the mixture is stirred at — 5° to 0° for an additional 2 hours. Two liters of cold 10% hydrochloric acid is introduced at a rate which maintains the reaction mixture below 20° (Note 5). The solid which separates is isolated by suction filtration, washed sequentially with 11. of dilute hydrochloric acid and 21. of water, and air-dried. There is isolated 93-95 g. (96-98%) of the dimethanesulfonate having m.p. 66-67.5°. Reorystallization from methanol gives needles melting at 75-76° (Note 6). 

While the vast majority of the chemistry of thiolsulfonates involves reactions in which the sulfenyl sulfur acts as an electrophilic center and is attacked by nucleophiles, one example has been reported (Douglass, 1959) in which this same sulfur acts as a nucleophile. Methyl methanethiolsulfonate undergoes a very slow reaction with methanesulfenyl chloride that leads to the formation of methanesulfonyl chloride and dimethyl disulfide. The mechanism is believed... 

In a rearrangement reaction, 2-hydroxy-2-phenyl-2-(3-pyridinyl)acetic hydrazide, 102, reacts with methanesulfonyl chloride to generate a mixture of pyrrolo[2,3-. ]pyridine derivatives (Equation 42) <1998JHG145>. The proposed mechanism for the rearrangement involves intramolecular attack of compound 102 on a reactive pyridinium intermediate formed during the reaction. 

In certain cases in which the substrate carries an a hydrogen, there is strong evidence1728 that at least some of the reaction takes place by an elimination-addition mechanism (ElcB, similar to the one shown on p. 382), going through a sulfene intermediate,1729 e.g., the reaction between methanesulfonyl chloride and aniline. 

A mechanically stirred solution of aniline (139.7 g, 1.5 mol) in pyridine (2 L), under N2 is cooled in an icebath. Methanesulfonyl chloride (171.8 g, 1.5 mol) is added dropwise to this solution while the temperature is maintained at 15°-20°C, which results in a red-orange color change in the reaction mixture. 

Mechanism of Reaction of Methanesulfonyl Chloride and Anhydride with Trialkylamines and Water or Alcohols Multiexchange of Hydrogen with Small Amines... 

The preceding section dealt primarily with the evidence that demonstrated sulfenes to be intermediates in these processes and also, where the evidence warranted it, with the mechanism of the sulfene formation. A continual point of concern is whether or not the reaction is really proceeding by way of the sulfene or not. In this section we shall attempt to find what circumstances of substrate, base and (where different) nucleophile tend to lead to the elimination-addition (sulfene) reaction, and which to some other process, notably the direct displacement reaction. Sometimes, indeed, it takes only a rather small change in conditions to alter the mechanism completely. For example, it has been noted above that azide ion reacts with a-disulfones or sulfonyl chlorides by the direct displacement49. This is also seen in the reaction of methanesulfonyl chloride with aqueous sodium azide when the... 

A further variation in mechanism is found with methanesulfonyl chloride and p-toluidine. The reaction with triethylamine goes via the sulfene, but with pyridine by a direct displacement88, perhaps involving general base catalysis. The key variable in this case would appear to be the basicity of the amine with A-ethylmorpholine (pKa 7.7) the sulfene route predominated (< 87%) but with iV-methylimidazole (pKa 6.95) it was the minor pathway ( 20%). Phenylmethanesulfonyl chloride, it may be noted, reacts by the sulfene pathway with either pyridine or triethylamine and p-toluidine88. 

Tosylates (p-toluenesulfonates) are made by treating alcohols with p-toluenesulfonyl chloride (or tosyl chloride) in the presence of pyridine. A similar reaction (but with a different mechanism, which we will discuss in Chapter 17) with methanesulfonyl chloride (mesyl chloride) gives a mesylate (methanesulfonate). 

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