Cyclohexyl methanesulfonate

Kotsuki et al.203 have reported high yields of alkylated products formed in the presence of triflic acid using cyclohexyl methanesulfonate [Eq. (5.79)]. Similar performance was found for mesitylene, durene, and naphthalene, as well as for other secondary alcohol methanesulfonates. 

Two of the most commonly used sulfonyl chlorides are p-toluenesulfonyl chloride (abbreviated tosyl chloride, TsCl) and methanesulfonyl chloride (abbreviated mesyl chloride, MsCl). Treating ethanol with p-toluenesulfonyl chloride in the presence of pyridine gives ethyl p-toluenesulfonate (ethyl tosylate). Pyridine is added to catalyze the reaction and to neutralize the HCl formed as a by-producf. Cyclohexanol is converted to cyclohexyl methanesulfonate (cyclohexyl mesylate) by a similar reaction of cyclohexanol with methanesulfonyl chloride. 

Typically, the organic substrate in these reactions is a haloalkane. Primary haloalkanes will generally give 100% substitution products, but tertiary and cyclohexyl halides usually undergo 100 % elimination, with secondary haloalkanes producing a mixture of the two. Studies of the chloride and bromide displacements of (R)-2-octyl methanesulfonate have shown that phase transfer displacements proceed with almost complete inversion of stereochemistry at the carbon centre, indicating an Sjv2-like mechanistic pathway [41],... 

Sequential treatment of 3-acetylthiazolidine-2-thione (1055) with stannous trifluoro-methanesulfonate, diamine 1057, and methyl pyruvate results in the formation of adduct 1058 with S5Vo ee. The 1-naphthyl group on the pyrrolidine system is essential to ensure high asymmetric induction. Other groups such as cyclohexyl, phenyl, 2,6-xylyl, or 2-naphthyl... 

An example illustrating this possibility is the reaction of sodium diethyl phosphite with methanesulfonate of cis- and tra 3 -tert-butyl-4-cyclohexanols. The products of this interaction are 3-ieri-butylcyclohexene I, (4-feri-butyl) cyclohexyl diethylphosphite II and (4-iert-buty) cyclohexanedialkylphosphonate III [355],... 

As expected for a bimolecular process, the reaction is faster with primary than with secondary halides. Likewise, -octyl methanesulfonate was found to undergo cyanide displacement at a greater rate than did the corresponding bromide. Moreover, elimination competes with substitution in the case of secondary halides elimination was the exclusive process observed in the reaction of cyanide ion with cyclohexyl halides. 

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