Corey-Winter reductive elimination

Transformation of diols to the corresponding olefins by sequential treatment with l,r-thiocarbonyldiimidazole and trimethylphosphite. Also known as Corey-Winter reductive elimination, or Corey-Winter reductive olefmation. 

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. 

Double bonds can be created by a number of available stereospecific reactions (E2 elimination, pyrolytic elimination, e.g. Cope, Chugaev reactions), stereoselective Wittig and related reactions, reduction of triple bonds, by cisitrans isomerisation of existing double bonds either photochemically or by wet chemistry, e.g. the Corey-Winter procedure. [17]... 

Cope Elimination Reaction Cope Rearrangement Corey-Bakshi-Shibata Reduction Corev-Kim Oxidation Corey-Winter Olefin Synthesis Comforth Rearrangement Coumarin-Benzofuran Ring Contraction Crafts (see Friedel-Crafts Reaction)... 

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