2- Chloroethanesulfonyl chloride

Virtually all of the vast number of methanesulfonate, or mesylate , esters prepared to facilitate elimination or substitution of a hydroxyl function have been prepared from sulfene the standard procedure using methanesulfonyl chloride and triethylamine in dichloromethane has been described by Crossland and Servis138. To be sure, sulfene intermediacy is not required for alkanesulfonate ester formation the reaction, as has been noted (in Section IV.A.2), will proceed without base promotion via the direct displacement route, but it is usually sufficiently sluggish, however, that the further reaction of the ester with the alcohol competes with ester formation139. This makes the procedure a poor one for most practical purposes, although we recently encountered an instance, namely the preparation of neopentyl 2-chloroethanesulfonate87, in which the direct reaction of the alcohol and sulfonyl chloride without base was the method of choice this arose because (a) the product is stable and (b) 2-chloroethanesulfonyl chloride does not yield the corresponding sulfene with tertiary amines (Section IV.A.2). 

To a round-bottomed flask equipped with a gas inlet tube and a dry ice cooled condenser, was added 1.0 mol ethyl chloride and 2.34 mol sulfur dioxide. Then 1.31 mol chlorine was slowly passed into the ethyl chloride and sulfur dioxide mixture through the gas inlet within 3.5 h while illuminated by one or two Westinghouse RS 275-watt sunlamps at a distance of about 6 in. The reaction mixture was first separated by atmosphere pressure distillation from a water bath, and the low-boiling fraction was added to 20% NaOH solution frozen at -70°C and warmed slowly to 0°C to remove HCl, SO2, and SO2CI2. Then the aqueous solution was neutralized with HCl, and the dichloroethanes were separated by steam distillation to give 6-7% 1,2-dichloroethane (b.p. 83°C) and 11.2-12.2% 1,1-dichloroethane (b.p. 57°C). The residue from initial distillation was further subjected to vacuum distillation to give 26.6% 2-chloroethanesulfonyl chloride as a water white lachrymatory liquid, b.p. 84°C at 12 mmHg. (Note The author has no idea about the status of 20% NaOH solution frozen at -70°C, i.e., whether it is a solid, semi-solid or a solution). 

Chloroethane 2-Chloroethanesulfonyl chloride 2-Chloroethanol 2-Chloroethanol, 4-methylbenzenesulfonate Chloroethene... 

A furan-containing chiral alcohol reacted with p-chloroethanesulfonyl chloride, through an intramolecular Diels-Alder cyclization, to form the endo sultone isomer after thermal equilibration, as shown in the following scheme. The sultone was further converted into a substituted cyclohexene, which was a key intermediate in the total synthesis of 1,10-seco-eudesmanolides eriolanin and eriolangin <04AG(E)5991>. 

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