Selenides, preparation 1-hydroxy, from epoxides

P-Hydroxy selenides are conveniently prepared from epoxides by treatment with sodium phenylse-lenide (Scheme 32) and by the addition of benzeneselenenic acid and its derivatives to alkenes (Scheme 33), - -" although in some cases these reactions are not regioselective. Useful phenylseleno -etherification and -lactonization reactions have been developed which can be regioselective (equation 42 and Schemes 34 and 35). -" " Selenide- and selenoxide-stabilized carbanions have been used in addition reactions with aldehydes and ketones, - and the reduction of a-seleno ketones also provides a route to P-hydroxy selenides. ... 

Epoxides can also be prepared from a variety of 3-functionalized alcohols such as p-hydroxy sulfoxides," p-hydroxysulfonium salts," P-hydroxy selenides" and vicinal diols. In the use of unsymmetri-... 

Epoxides via methyl selenoacetals. Krief et al. have reported the synthesis of epoxides from two carbonyl compounds. The first step involves preparation of a dimethyl selenoacetal (1), followed by conversion to an a-methyl seleno-carbanion (a). These highly reactive carbanions react with even hindered carbonyl compounds to give 0-hydroxy methyl selenides (2), which are converted into selenonium salts by reaction with methyl iodide or dimethyl sulfate. 

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