Octyl triflate

On the other hand, when optically active 2-octyl triflate (197) was hydrolyzed in the solubilized state with surfactant concentrations greater than their CMC, the stereochemical course changed to net retention (ca. 48% for CTAB, and ca. 27% for NaLS)193 The rate constants, very much lower than those in the absence of micelles, indicate that the reaction proceeded in the micelles. The different behavior of (196) and (197), particularly in the presence of cationic micelles (CTAB), may be due to the greater efficiency of triflates in producing carbocations. The comparison of (196) and (197) then suggests that the solvation model of micellar stereochemical control applies to unassisted solvolyses whereas the double inversion mechanism operates with leaving groups which invite participation of a nucleophile. 

Precomplexation of ATPH with 2-methylcyclohexanone (49) at -78 °C in toluene was followed by treatment with LDA in tetrahydrofuran (THF) and the mixture was stirred for 1 h. Subsequent treatment with methyl trifluoromethanesulfonate (MeOTf) furnished 2,2-dimefhylcyclohexanone (51) and 2,6-dimethylcyclohexa-none (50) in an isolated yield of 53% in a ratio of 32 1. Similarly, highly regiocon-troUed alkylation of unsymmetrical 52 and 53 with octyl triflate (OctOTf) was achieved to give 54 and 55, respectively (>99 1) (Scheme 6.31). Replacing ATPH with MAD resulted in lack of regioselectivity (50 51= 1 1). 

For the synthesis of various ethers from alcohols, the combination of alkyl triflate and Proton Sponge (1) is available. The (9-alkylation reaction of symmetrical alcohol proceeds in high yield with octyl triflate in the presence of Proton Sponge (1) as abase (Scheme 8.6a). Low yields were obtained with triethylamine or DMAP instead of Proton Sponge (1) [14]. Octadecenyl triflate was also effectively alkylated with the alcohol in the presence of Proton Sponge (1) in 66% yield [15] (Scheme 8.6b). 

Acetolysis of the cyclopropyl triflates (312—314 R = Me) proceeds rapidly at ambient temperatures with small, but significant, rate differences (Scheme 39). Secondary a-deuterium isotope effects have been obtained for the parent triflates and the data indicate concerted allylic ion formation from (312), unopened ion production from (313), and a partially opened ion from (314) with the charge largely at C-7 3-exo-tricyclo[3,2,l,0 ]octyl triflate has also been studied. In addition, Creary has... 

A synthetically useful virtue of enol triflates is that they are amenable to palladium-catalyzed carbon-carbon bond-forming reactions under mild conditions. When a solution of enol triflate 21 and tetrakis(triphenylphosphine)palladium(o) in benzene is treated with a mixture of terminal alkyne 17, n-propylamine, and cuprous iodide,17 intermediate 22 is formed in 76-84% yield. Although a partial hydrogenation of the alkyne in 22 could conceivably secure the formation of the cis C1-C2 olefin, a chemoselective hydrobora-tion/protonation sequence was found to be a much more reliable and suitable alternative. Thus, sequential hydroboration of the alkyne 22 with dicyclohexylborane, protonolysis, oxidative workup, and hydrolysis of the oxabicyclo[2.2.2]octyl ester protecting group gives dienic carboxylic acid 15 in a yield of 86% from 22. 

They have been prepared with several anions,332-335 the tetrafluoroborate salt exhibits SA and Sc phases332,333 but the triflate shows a nematic phase 334 One of the problems in studying these complexes was the very high temperatures at which the phases existed and the fact that decomposition was often observed in the upper reaches of the SA phases. Reduction of these temperatures was achieved by changing the small anions for dodecyl sulfate that also make that more materials exhibit nematic SA and Sc phases, and another more viscous phase appeared, named cubic phase So- With the anion octyl sulfate336 the crystal structure of one of the complex with 4-metoxystilbazole could be achieved (20), with this anion the cubic phase was not present. 

Enantiomerically pure 3-oxo-8-oxabicyclo[3.2.1]octyl-2-yl derivatives were obtained by [4 -h 3] cycloaddition of furan with chiral 1,2-dioxyallyl cation engendered in situ by acid-catalyzed heterolysis of enantiomerically pure, mixed acetals derived from 1,1-dimethoxy-acetone and enantiomerically pure, secondary benzyl alcohols [203]. For instance, mixed acetal 439 is converted into the silyl enol ether 440. In the presence of a catalytic amount of trimethylsilyl triflate, 440 generates a cationic intermediate that adds to furan at - 95°C, giving... 

Other Alkylation Experiments. In other experiments lithium and sodium were used in place of potassium. Biphenyl and anthracene were used in place of naphthalene. 1,2-Dimethoxyethane was used in place of tetrahydrofuran. Butyl chloride, butyl bromide, butyl mesylate, butyl triflate, methyl iodide, and octyl iodide were used in place of butyl iodide. The conditions used in these experiments were very similar to the conditions used in the procedures described in the previous paragraphs. The isolation procedure was modified in those cases where the ionic salt, e.g., sodium iodide, was soluble in tetrahydrofuran. In these instances the tetrahydrofuran-soluble product was washed with water to remove the salt prior to further study. 

Solvolysis of the triflate ester of quadricyclyl-7-carbinol (126) in trifluoroethanol containing triethylamine gave (127 80%) and four minor products. Clearly a cyclo-propylethyl carbonium ion rearrangement is involved rather than a direct 1,2-shift to give the quadricyclyl-octyl system (128). ... 

Ionic liquids (IL) can be used as solvents for nucleophilic substitution reactions of alkyl halides or tosylates with NaN3. ° The authors studied three ionic liquids (84 and 85), [bmim][PF6], [bmim][N(Tf)2]> [hpyr][N(Tf)2] (where bmim = l-butyl-3-methyl-imidazo-lium, hpyr = 1-hexylpyridinium, PFg = hexafluorophosphate, N(Tf)2 = bis(trifluoromethy lsulfonyl)imide). It was observed that nucleofugacity scales for this reaction are similar to those reported for the same process in cyclohexane. It was also observed that elimination reaction does not compete with substitution even in cases with sterically hindered substrates such as the triflate ester of diacetone-D-glucose 81. The nucleophilic displacement on n-octyl mesylate (86) with potassium azide in a biphase system of supercritical carbon dioxide (SCCO2) and water, in the presence of catalyst Bu4PBr is also an adequate medium for the synthesis of the corresponding azide 87 ° (Scheme 3.11). 

EMIM = l-ethyl-3-methylunidazolium CF3SO3 = triflate anion ( ) BMIM = l-n-butyl-3-methylimidazolium < ) Oc = octyl Ts = H3CC6H4-SO2 (tosyl). 

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