4-Methoxyphenyl tosylate

Bis(p-methoxyphenyl) tellurium diacetate or ditosylate is generated by the electrolysis of the parent telluride in the presence of BU4N+ acetate or tosylate. Like the telluroxide, they accomplish the conversion of thioamides into nitriles and 1,2,4-thiadiazoles. Taking into consideration of these facts, the above conversion can be performed in an electrochemical... 

Coniferyl alcohol [4-hydroxy-3-methoxy-cinnamyl alcohol, 3-(4-hydroxy-3-methoxyphenyl)-2-propen-l-ol] [458-35-5] M 180.2, m 73-75°, 73-75°, b 163-165°/3mm. It is soluble in EtOH and insoluble in H2O. It can be recrystd from EtOH and distd in a vacuum. It polymerises in dilute acid. The benzoyl derivative has m 95-96° (from pet ether), and the tosylate has m 66°. [derivatives Freudenberg and Achtzehn B 88 10 1955, UV Herzog and HillmerR64 1288 1931. ... 

It was found that TFAA is an excellent reagent for achieving the direct acylation of A -sulfonylpyrroles 384 by carboxylic acids leading to 2-acylpyrroles 385 in good yield (Equation 89) <2004TL9573>. A few or none of the isomeric 3-acyl derivatives are formed. Only in the example involving acetylation of 2-(4-methoxyphenyl)-A -tosyl-pyrrole was an isolable amount (11%) of a 2-trifluoroacetyc derivative formed. 

Thiazole A -oxides can easily be alkylated on the oxygen. For example, Ar-(alkoxy)-5-(p-methoxyphenyl)-4-methylthiazole-2(377)-thiones were prepared from Ar-(hydroxy)-5-( -methoxyphenyl)-4-methylthiazole-2(3//)-thione tetraethylammonium salt and an appropriate alkyl chloride or tosylate in moderate to good yields <20060BC2313>. A -Methoxythiazole-2(377)-thiones were synthesized from the A -hydroxythiazole-2(3//)-thiones by treatment first with a tetraalkylammonium hydroxide in methanol and then methyl ra-toluenesulfonate in DMF <2005EJ0869>. 

Abbreviations Ac acetyl AIBN azobisisobutyronitrile All allyl Bn benzyl Bz benzoyl ClAc chloroacetyl DAST diethylaminosulfur trifluoride DBU l,8-diazabicyclo[5.4.0]-undec-7-ene DDQ 2,3-dichloro-5,6-dicyano-/)-benzoquinone DMDO dimethyldioxirane DMTST dimethyl(methylthio)sulfonium trifluoromethanesulfonate Fmoc 9-fluorenyl-methoxycarbonyl HDTC hydrazine dithiocarboxylate IDCP iodonium di-collidine perchlorate Lev levulinoyl MBz 4-methylbenzoyl Me methyl MEK methyl ethyl ketone MP 4-methoxyphenyl NBS iV-bromosuccinimide NIS A-iodosuccinimide Pent n-pentenyl Pfp pentafluorophenyl Ph phenyl Phth phthaloyl Piv pivaloyl PMB 4-methoxybenzyl TBAF tetrabutylammonium fluoride TBDMS tcrt-butyldimethylsilyl TBDPS tert-butyldiphenylsilyl TCA trichloroacetyl TES triethylsilyl Tf trifluoromethanesulfonyl TMS trimethylsilyl Tol 4-methylphenyl Tr trityl Troc 2,2,2-trichloroethoxycarbonyl Ts tosyl. 

The PMB ether, also referred to as an MPM ether [(4-methoxyphenyl)methyl], is less stable to acids than a benzyl ether. Its utility as a protecting group stems from the fact that it can be removed oxidatively with DDQ (2,3-dichloro-5,6-dicyano-l,4-benzo-quinone) under conditions that do not affect protecting groups such as acetals, RO-Bn (or RO-BOM), RO-MOM, RO-MEM, RO-THP, RO-TBS, benzoyl, tosyl, or acetate groups, nor do they affect epoxides or ketones. Alternatively, RO-PMB ethers can be cleaved with (NH4)2Ce(N03)6. ... 

Metathesis of tetraarylbismuthonium halides with metal salts has often been used to exchange the halide anion for other anionic species (Section 3.3.1). For example, the reaction between tetrakis(2-methoxyphenyl)bismuthonium chloride and sodium or silver salts of formate, tosylate, bromide, iodide, tetrafluoroborate or perchlorate yields the corresponding bismuthonium compounds of the type [Ar4Bi ]Y (Ar = 2-methoxyphenyl Y = OCOH, OTs, Br, I, BFj, CIO4) [97JCS(P1)1609]. 

The solvolysis of 2/ ,3>S -3-(4-methoxyphenyl)but-2-yl tosylate in acetic acid can be followed by several kinetic measurements (a) rate of decrease of observed rotation ( ) rate of release of the leaving group k,) and (c) when 0-labeled sulfonate is used, the rate of equilibration of the sulfonate oxygens in the reactant (A ). At 25 °C the rate constants are ... 

Single-crystal X-ray structures have been reported for the following aryl- and heteroaryliodo-nium salts diphenyliodonium triiodide [412], (2-methylphenyl)(2-methoxyphenyl)iodonium chloride [413], (2-methoxy-5-methylphenyl)(4-methoxy-2-methylphenyl)iodonium trifluoroacetate [414], (2-methoxy-5-methylphenyl)(4-methoxyphenyl)iodonium trifluoroacetate [415], a complex of diphenyliodonium tetrafluoroborate with pyridine [416], a complex of diphenyliodonium tetrafluoroborate with 1,10-phenanthroline [417], a complex of diphenyliodonium tetrafluoroborate with 18-crown-6 [418], 1-naphthylphenyliodonium tetrafluoroborate [419], 3,10-dimethyl-10//-dibenzo[, e]iodinium tetrafluoroborate [420], aryl(pentafluorophenyl)iodonium tetrafluoroborates [421], 4,4 -[bis(phenyliodonium)]-diphenylmethane ditriflate [422], [bis(4-methoxyphenyl)](diethylaminocarbodithioato)iodine(in) [423], di(p-tolyl)iodonium bromide [424], diphenyliodonium chloride, bromide and iodide [425,426], diphenyliodonium nitrate [427], diphenyliodonium tetrafluoroborate [428], thienyl(phenyl)iodonium salts [401], (anft-dimethanoanthracenyl)phenyliodonium tosylate and hexafluorophosphate [429] and 3-mesityl-5-phenylisoxazol-4-yl(phenyl)iodonium p-toluenesulfonate [409]. 

It is noteworthy that these correlations are also quite acceptable without the inclusion of any nucleophilic participation terms. The lower a value than for the tert-hvXy halides is partially a temperature effect, but probably also reflects charge delocalization in the leaving tosylate group as well as in the forming carbonium ion (through anchimetric assistance by the p-methoxyphenyl group). 

Somfai s group demonstrated the use of a Lil-promoted vinylaziridine-3-pyrroline rearrangement in the formal synthesis of the antibiotic (-)-anisontycia The commercially available 2-(4-methoxyphenyl)acetaldehyde 43 was subjected to Brown allylation followed by aminolysis of the resulting chlorohydrin to afford the enantioenriched aminoalcohol 44 f Scheme 11.34). The enantiopure cis-vinylaziridine 45 was then prepared by O- and N-tosylation of the chiral aminoalcohol followed by KOH-promoted ring closure. Microwave-assisted rearrangement of vinylaziridine 45 using Lil as an additive afforded enantioenriched 3-pyrroline 46 in excellent yield, and this was converted to the natural product in several steps tScheme 11.34T ... 

Scheme 8.34. The conversion of l-(o-methoxyphenyl)-2-methylpropene to the corresponding trifluoromethyi ether (and ketone) by (a) bromination and dehydrohalogenation, (b) siiver ion-assisted substitution of bromine by tosylate (presumably via the vinylic cation), and (c) SnI substitution of trifluoroethanol for tosylate.

The solvolysis of trityl derivatives in strongly acidic aqueous media has also been examined. Rates of hydrolysis were correlated to Hr acidity function and theX excess acidity scale. The solvolysis and substitution reactions of 2-(4-methylphenyl)ethyl tosylate have also been studied. " In trifluoroethanobwater (50 50) solution, the corresponding phenonium ion is generated. The kinetics of azide trapping has been studied and compared with results from an analogous system 2-(4-methoxyphenyl)ethyl tosylate. Owing to electronic effects, the methyl-substituted phenonium ion is a more reactive electrophilic species. 

Methoxyphenyl)methyl 4-methylbeiizenesu]fonate (A primary benzylic tosylate)... 

Small amount of water (10-50 equiv.) are able to affect the stereoselectivity of the products between 9-tosyl-3,4-dihydro-P-carboline and ketones in the presence of L-proline as a catalyst in DMSO (Scheme 24.5a) [131]. This effect was also observed in CH2CI2 and acetone, although it cannot be fully rationalized. Later, proline gave rise to high stereoselectivities in the catalytic reaction of aqueous tetrahydro-2H-pyran-2,6-diol with N-(p-methoxyphenyl) (PMP) aldimines in DMSO to afford the corresponding tetrahydropyridines via a Mannich-type/ intramolecular cycUzation cascade reaction (Scheme 24.5b) [132]. 

Fluorovinyl tosylate 40 was stereoselectively prepared from commercially available 2,2,2-trifluoroethyl tosylate in two steps. A pure ( )-40, isolated by column chromatography, was used in the Suzuki-Miyaura coupling with (4-methoxyphenyl)boronic acid, and ( )-(2-fluorovinyl)-4-methoxybenzene 41 was obtained stereoselectively [66] (Scheme 14). 

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