Reactions from epoxides, thionocarbonates and episulfides

The affinity of trivalent phosphorus for oxygen (and sulfur) has been put to use for the deoxygenation of epoxides and desulfurization of episulfides, which leads to alkenes. n vR 

Episulfides, generated from diazo compounds and a thioketone, can also undergo desulfurization with phosphines to give alkenes (see section 4.3.7). 

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