4-Penteneselenothioic acid S-alkyl esters: Synthesis via the seleno-Claisen rearrangement

Selenothioic acid S -alkyl esters were reacted with allylic bromides in the presence of Et 3 N. Mono-, di- or tri-allylatd products were selectively formed by changing reaction temperatures, times and allylic bromides used. The reaction proceeded with high regio- and stereoselectivity via the seleno-Claisen rearrangement. The selective synthesis of monoallylated esters was also attained by the reaction of in-situ generated lithium eneselenolates with allylic bromides.