Tosylates, preparation

A mixture of 0.30 mol of the acetylenic tosylate (prepared according to the general method described in VlII-3, Exp. 3 from the corresponding acetylenic alcohol, which was prepared from HC=CHgBr and CgHi3CH=0 in THF, as described in Ref. l)and 100 ml of dry acetone was added to a solution of 0.40 mol of anhydrous... 

Cyclohexaamylose continued) mono-6-O-tosyl-, preparation of, 23 250 pyridine-2,5-dicarboxylic acid derivative, catalytic action of, 23 251 separation of, by complexing, 23 214 structure, stereochemistry and physical properties of, 23 210-213... 

A multi-step reaction sequence was then realized to prepare the precursor (178) for the pivotal macrocyclization reaction. Alternate stepwise chain elongations were achieved according to Schemes 28 and 29. Reaction of the tosylate prepared from the alcohol 162 with lithium acetylide afforded the alkyne 174 (Scheme 28). Following the introduction of a tosylate at the upper branch, a one-carbon chain elongation of the terminal alkyne afforded the methyl alkynoate 175. A methyl cuprate 1,4-addition was used to construct the tri-substituted C double bond stereoselectively. For this purpose, the alkynoate 175 was initially transformed into the Z-configured a,/ -unsat-... 

Alkynyl(phenyl)iodonium Tosylates Preparation and Stereospecific Coupling with Vinylcopper Reagents. Formation of Conjugated Enynes P. J. Stang and T. Kitamura, Department of Chemistry University of Utah, Salt Lake City, UT 84112... 

The enolate also reacted diastereoselectively with the epoxy-tosylate prepared earlier. The epoxide, being more electrophilic than the tosylate, is opened first, giving an alkoxide, which closes again to give a new epoxide. 

The di-O-tosylates (prepared by action of tosyl chloride in pyridine) are reduced with zinc (Nal/Zn route e Tipson-Cohen reaction) [13]. Cyclic ortho-esters (prepared by reaction of the diol with ethyl orthoformate) are transformed into olefins by simple heating in the presence of acids (Eastwood reaction, route b) [14]. Cyclic thiocarbonates (obtained by reaction of a diol with thiophosgene or (V,(V -thiocarbonyl-di-imidazole) are reduced to olefin with trimethyl phosphite (Corey-Winter method, route c) [15]. Finally, reduction of vicinal di-xanthates with tri- -butyltin hydride according to the Barton procedure [16] affords olefins via a reductive elimination process route a). The Corey-Winter, Garegg, and Tipson-Cohen methods are most commonly applied for deoxygenation of sugar diols. 

In case a tosyiate cannot be obtained analytically pure or cannot be analyzed, solvoiysis experiments may still be valid because the linearity of the first order plot and a comparison of the experimental infinity titer with that calculated are checks on purity. Also tosylates prepared from a mixture of isomers may yield valuable information if the rates of the components differ by a factor of 10 or more the mixture can be analyzed kinetically. ... 

ALKYNYL(PHENYL)IODONIUM TOSYLATES PREPARATION AND STEREOSPECIFIC COUPLING WITH VINYLCOPPER REAGENTS. FORMATION OF CONJUGATED ENYNES. 

TOSYLATES PREPARATION AND STEREOSPECIFIC COUPLING WITH VINYLCOPPER REAGENTS. FORMATION OF CONJUGATED ENYNES. I-HEXYNYL(PHENYL)-lODONIUM TOSYLATE AND (E)-5-PHENYLDODEC-5-EN-7-YNE... 

Nickel-catalysed SM reactions with aryl tosylates Preparation of methyl biphenyl-2-carboxylate (294) 145]... 

Sec. alkyl halides. NaBr added to dimethyl sulfoxide, then 3-amyl tosylate, prepared from 3-pentanol and tosyl chloride in pyridine (Y 78%), added, and shaken 90 hrs. pure 3-bromopentane (Y 85%). Overall Y 57-66%.—This... 

What is the configuration of the tosylate prepared from (i )-2-butanol What is the configuration of the iodide obtained by reacting that tosylate with iodide ion in acetone ... 

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