Thiophosgene reaction with diols

Oleic acid was converted to the erythro diol 264 or the threo diol 258 by reaction with permanganate or hydrogenperoxide respectively. The threo compound 258 was converted to the 9,11-dioxahomoprostanoids. Reaction with paraformaldehyde formed 259 or 260, phosgene converted the diol into 261 whereas reaction with thiophosgene gave compound 262. 

Cyclic thionocarbonates (41) can be cleaved to olefins (the Corey-Winter reaction)274 by heating with trimethyl phosphite275 or other trivalent phosphorus compounds276 or by treatment with bis(l,5-cyclooctadiene)nickeI.277 The thionocarbonates can be prepared by treatment of 1,2-diols with thiophosgene and 4-dimethyIaminopyridine (DMAP) 278... 

Conversion of 1,2-diols to alkenes. The cyclic thiocarbonate is available from reaction of the diol with thiophosgene or thiocarbonyldiimidazole, and reacts with added trimethylphosphite via a -elimination to the alkene. 

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. 

Olefin synthesis. Corey and Winter" devised a novel olefin synthesis from 1,2-diols utilizing in the first step the reaction with thiocarbonyldiimidazole (2), a reagent prepared from 2 moles of imidazole and 1 mole of thiophosgene. Corey postulated that treatment of the cyclic thionocarbonate (3) with a reagent which would abstract sulfur to form the curbenc (4) would effect cis elimination to the olefin and found that trimethyl phosphite effects this reaction cleanly and in high yield. [Pg.1350]

As mentioned in CHEC-I, the standard method for formation of l,3-dioxolane-2-thione (28) is reaction of ethanediol with thiophosgene, but other methods include the reaction of (289) with CSj to give (291) as described above, and reaction of diols (293) with base and CS2 followed by Mel which gives the thiones corresponding to (294) in addition to bis(dithiocarbonates) (230) <78S286>. 

Two new modifications of the synthesis of olefins from vicinal diols have appeared in the literature. Barua and Sharma have demonstrated that both cis and fra/M-secondary-tertiary 1,2-diols are readily converted (in a mild manner, and in excellent yields) into olefins by using chlorotrimethylsilane and sodium iodide in acetonitrile at room temperature, Corey and Hopkins have improved the thionocarbonate olefin s mthesis by modification of the reaction conditions to allow sensitive and complex diols to be converted into olefins. Thus, the reaction of 1,2-diols with thiophosgene affords the thionocarbonates (39) in... 

Carbonates as well as thiocarbonates, for example, (Ja)-120 <2004TL39>, (R)-248 <1999CL93>, and (R)-249 <1998JA4530>, were readily prepared by reaction of the corresponding diol with triphosgene and thiophosgene. 

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