Corey-Hopkins olefination

A modification is the Corey-Hopkins olefination. See Tetrahedron Letters, 1982,23, 1979 ... 

The absolute configuration of radiosumin, a novel potent trypsin inhibitory dipeptide, was determined by T. Shioiri and co-workers by carrying out the first enantioselective total synthesis of the natural product. The s-trans 1,3-diene in one of the key synthetic intermediates was installed by the Corey-Winter olefination using the Corey-Hopkins reagent (1,3-dimethyl-2-phenyl-1,3,2-diazaphospholidine). 

There have been several modifications to the Corey-Winter reaction, the most significant of which was published by the Corey group in 1982.9 Corey and Hopkins reported that by using a diazaphospholidine in place of trimethylphosphite, thionocarbonates could be converted to the corresponding olefins at significantly lower temperatures. Thus, thionocarbonate 20 was prepared from diol 19 in 93% yield, and subsequent treatment of 20 with diazaphospholidine 21 afforded olefin 22 in 88% yield. Several complex examples were disclosed in which olefins were generated in 70-94% yield.9... 

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... 

---