An Effective Method for the Synthesis of 3,5-bis(halomethyl)-1,4-Oxaselenanes and their Derivatives.

We report the first study of selenium dichloride and dibromide reactions with diallyl ether, aimed at the preparation of selenium-containing heterocyclic compounds. It was established that selenium dichloride reacted regio- and stereoselectively, giving cis-3,5-bis(chloromethyl)-1,4-oxaselenane in 70% yield. Selenium dibromide gave 3,5-bis(bromomethyl)-1,4-oxaselenane in 76% yield, as a mixture of cis and trans diastereomers. The obtained compounds were used for the synthesis of previously unknown 1,4-oxaselenanes: 3,5-bis(methoxymethyl)-, 4,4-dibromo-3,5-bis(chloromethyl)-, and 3,5-bis-(bromomethyl)-4,4-dichloro-1,4-oxaselenane. The diastereomers of 3,5-bis(halomethyl)-1,4-oxa-selenanes were found to undergo unusually facile isomerization. [ABSTRACT FROM AUTHOR]