Tosylate ion

Acetate ion Octadecyl tosylate Octadecyl acetate Tosylate ion y... 

Electrophiles, such as C—Hal functions, contained in side chains may be well positioned for interaction with ring heteroatoms. Thus, Af-t-butyl-2-tosyloxymethylaziridine in ethanol displaces tosylate ion from the side chain, and nucleophilic opening of the resulting azabicyclobutanonium ion by solvent gives 3-hydroxy- and 3-ethoxy-azetidine (Section 5.09.2.3.2). 

Another HTIB-mediated method resulting in lactone 97 is carried out from 4-pentenoic acid (96). The reaction probably involves the capture of one end of the carbon-carbon double bond with tosylate ion and the other with the carboxyl function of the substrate (86TL4557) (Scheme 27). In a similar way, 96 reacts with [hydroxy(bisphenoxyphosphoryloxy)iodo]ben-zene to yield 5-(bisphenoxyphosphoryl)oxy-4-pentanolactone (88JA2987) (Eq. 22). 

The replacement of a halide or tosylate ion, extending the carbon chain by one atom and providing an entry to carboxylic acid derivatives, has been a reaction of synthetic importance since the early days of organic chemistry. The classical conditions for preparing nitriles involves heating a halide with a cyanide salt in aqueous alcohol solution ... 

Aroyl esters of anthracene-9-methanol are photolysed in methanol to give products consistent with the anthracene-9-methyl cation as an intermediate.41 Rate constants for the solvolyses of secondary alkyl tosylates in fluorinated solvents were analysed in terms of the possible involvement of very short-lived carbocation-tosylate ion pair intermediates.42 The effect of added electrolytes on the rate of solvolysis of cumyl chloride and its -methyl derivative was studied in 90% aqueous acetone and 80% aqueous DMSO, with the results revealing a combination of a special salt effect and a mass law effect.43 Kinetic parameters obtained for the solvolysis of (8) (R1 = R2 = Me and R1 = Ar, R2 = H) show that there is substantial n, n participation in the transition state [e.g. (9). 44... 

The assignment of the configuration of the deoxyiodonucleoside as being arabino (CVIa) or ribo (CVIb) is surely warranted. The arabino configuration could arise by inversion at C2, with displacement of the tosylate ion of LXXXVI. The fact that the deoxyiodonucleoside (CVI), as well as LXXXVI (R = H), is converted to the anhydronucleoside LXXXVII by means of methanolic ammonia126 would be consonant with either configura-... 

The following reaction shows the SN2 displacement of tosylate ion ( OTs) from (.V)-2-butyl tosylate with inversion of configuration. The tosylate ion is a particularly stable anion, with its negative charge delocalized over three oxygen atoms. 

The phthalimide anion is a strong nucleophile, displacing a halide or tosylate ion from a good Sn2 substrate. Heating the /V-alkyl phthalimide with hydrazine displaces the primary amine, giving the very stable hydrazide of phthalimide. 

However, the comparatively low rate increase obtained for methyl tosylate must be due to the more positive value of Ig he tosylate ion itself has a less... 

The recovered tosylates on the other hand contained more D at C(9) than the isolated acetates (approximately twice as much in the recovered tosylate from the solvolysis of [395] compared with that recovered from the solvolysis of the mixture). These results indicated stereospecific rearrangement via internal return of the tosylate ion pair. 

Acac = acetyacetonate BArf = tetra(3,5-bis(trifluorome-thyl)phenyl)borate anion bridge = 1,3-diisocyanopropane COD = cycloocta-1,5-diene COE = cyclooctene DFT = Density Functional Theory dimen = 2,1,8-diisocyanoment-hane DMAD = dimethylacetylene dicarboxylate DMSO = dimethylsulfoxide dpmp = bis(diphenylphosphinomethyl) phenylphosphine DPPB = l,4-bis(diphenylphosphino)but-ane DPPE = l,2-bis(diphenylphosphino)ethane DPPM = bis(diphenylphosphino)methane en= 1,2-diaminoethane hfac = hexafluoroacetylacetonate HFB = hexafluorobut-2-yne HOTf = trifluoromethanesulfonic acid (triflic acid) MLCT = Metal Ligand Charge Transfer MO/MM = Molecular Orbital/Molecular Mechanics NBD = bicyclo[2. 2.1]heptadiene OTf = trifluoromethanesulfonate (triflate) ion OTs = p-toluenesulfonate (tosylate) ion /j-anis = /7-MeOC6H4 pip = piperidine pn = 1,2-diaminopropane PPN+ = bis(triphenylphosphine)iminium cation p-to = p-MeCeUt pz = pyrazolate QM/MM = Quantum Mechan-ics/Molecular Mechanics TFB = tetrafluorobenzobarrelene TM4 = 2,5-diisocyano-2,5-dimethyIhexane tn = 1,3-diami-nopropane. 

The peak at 26.2 ml in Figure 1 having UV/ARI 8000 could be due to the complex produced by adding an oxazollne unit at one or both ends of PEG dltosylate. The absorbence of the tosylate ion is lower than that of the ester. [The molar extinction coefficient of ethyl tosylate is 440 and that of silver tosylate is 223 at 254 nm (20).1 However, oxazollnium ions also absorb strongly at 254 nm. 

Even though the tosylate ion absorbs less than the ester, the absorbence could be made up by the oxazollnium ion. As can be seen in Figure 1, the experimental error involved is quite large and differences in UV/ARI of about +25% could go undetected. 

D-l-Deoxy-l-fluoroglycerol 3-phosphate (59), a potential anticancer agent, has been prepared from D-mannitol (60) by a stereospecific route which should be suitable for the synthesis of the L-isomer of (59).i 8 Transformation of (60) into D-l-tosyl-2,3-0-isopropylideneglycerol, followed by displacement of tosyl ion by fluoride ion, removal of the isopropylidene group, and treatment with dibenzyl phosphorochloridate gave the dibenzyl ester of (59). A DL-mixture of this dibenzyl ester was... 

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