2-Octyl methanesulfonate

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],... 

Alkylation of phthalimide anion can be carried out under solid-liquid phase-transfer conditions, using phosphonium salts or ammonium salts. In the reaction systems using hexadecyltributylphosphonium bromide, alkyl bromides and alkyl methanesulfonate are more reactive than alkyl chlorides. Octyl iodide is less reactive than the corresponding bromide and chloride. ( )-2-Octyl methanesulfonate was converted into (S)-2-octylamine with 92.5% inversion. Kinetic resolution of racemic ethyl 2-bromopro-pionate by the use of a chiral quaternary ammonium salt catalyst has been reported. Under liquid-liquid phase-transfer conditions, A -alkylation of phthalimide has been reported to give poor results. ... 

A mixture of (R)-2-octyl methanesulfonate, KCI, Iricaprylmethylammonium diloride, and water stirred and heated 1.5 hrs. at 100° (+)-(S)-2-dilorooctane. Y 74% optical purity 89.2%. Also bromides and fluorides, iodides with race-mization, and f. phase transfer catalysts, s. D. Landini, S. Quid, and F. Rolla, Synthesis 1975, 430 phase transfer catalysis, review, s. M. M kosza, Pure Appl. Chem. 43, 439 (1975). 

It is interesting to compare the nucleophilicity sequence found by Liotta and Grisdale (1975) for crown ethers, with the sequence recently reported by Landini et al. (1978) for onium compounds. For hexadecyltributylphos-phonium as the cation, the reactivity sequence (for n-octyl methanesulfonate) in chlorobenzene was CN- > > Cl- > Br- > I- > SCN- (Table 28), which... 

Table 5.3 The effect of catalyst structure and its organophilicity on the rate of reaction between n-octyl methanesulfonate and potassium bromide...

A study of the anion displacement reactions of n-octyl methanesulfonate reveals striking differences in the reactivity of various anions under phase transfer and homogeneous conditions [43], In the phase transfer catalysed reactions the reactivities of the anions were found to decrease in the order ... 

Table II. Catalytic Activity of Sandwich Ligands 1 and 2 in Nucleophilic Substitutions on n-Octyl Methanesulfonate with Alkali Halides (MY) under Solid-Liquid Conditions in Toluene at 50°C...

For example, in the nucleophilic substitution reaction of -octyl methanesulfonate with bromide in a chlorobenzene-water two-phase system the catalytic activity of Bu4N+Br was found to increase 20 times as the aqueous KBr concentration was increased from 1 to 6M [22]. 

TABLE 8 Influence of Steric Hindrance Around Cation on Rate Constant for Nucleophilic Displacement of w-Octyl Methanesulfonate with Bromide ... 

Nucleophilic displacements under two-phase conditions in the presence of catalytic amounts of crown ether, 4, which is completely dissolved in the organic phase, follow the classical PTC mechanism and the observed pseudo first-order rate constants are linearly correlated with the amount of complexed crown ether in the organic phase. A narrow reactivity range was found for different anionic nucleophiles in the displacement of n-octyl methanesulfonate (Scheme 10). 

TABLE 9 Nucleophilic Displacement of w-Octyl Methanesulfonate with Nucleophiles... 

The Sn2 displacement of -octyl methanesulfonate by bromide and iodide anions has been performed using silica-supported ammonium or phosphonium phase transfer catalysts with SCCO2 as solvent, both in SL- (stoichiometric amounts of functionalized silica) and LL-PTC (added aqueous KBr or KI) conditions [56]. The anionic reactivity is comparable to that found in conventional organic solvents however, environmental benefits and simple recovery of the catalyst through filtration are evident. 

In the nucleophilic displacement of n-octyl methanesulfonate (Eq. (17)) taken as standard substrate, by a series of anions, a rather restricted reactivity range in the following order was found > CN > Br = 1" > Cl > SCN . This is... 

Table 5. Second-order rate constants for the reaction of n-octyl methanesulfonate with various nucleophiles (Y ) under PTC conditions, and in anhydrous and wet homogeneous organic solutions...

Table 6. Solvent effect on the rate of the reaction of n-octyl methanesulfonate with bromide ion" under PTC and anhydrous homogeneous conditions...

Table 9. Reaction of n-octyl methanesulfonate with various nucleophiles (Y") under PTC conditions in the presence of perhydrodibenzo[18]crown-6(PHDB) or hexadecyl-tributylphosphonium salts...

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. 

Potassium cyanide has been caused to react with salts and esters of sulfonic acids to give nitriles. Thus, an intimate mixture of finely powdered potassium cyanide with the compound may be fused 422 this method was successfully applied428 to tetrahydrofurfuryl p-toluenesul-fonate and methanesulfonate, but failed with l,2 3,4-di-0-isopropylidene-6-O-tosyl-D-galactose. Another method, consisting of treatment of the ester with a stirred, boiling, saturated, aqueous solution of potassium cyanide gave885 a 70 to 83% yield of nitrile with primary p-toluenesul-fonates (ethyl, n-butyl, and n-octyl) and a 43% yield with a secondary p-toluenesulfonate (isopropyl). Similar methods had been applied earlier98 841 to such simple esters, but have not apparently found use with sulfonic esters of carbohydrates. 

Scheme 9 Poly(2,5-pyridine diyl) (PPY), methanesulfonic acid (MSA), octyl gallate (OG), and the possible schemes of interaction [233]...

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