The reaction of sodium diselenide with opticallyactive alkyl tosylates or chlorides is found to be a useful method for the synthesis of opticallyactive dialkyl diselenides. Opticallyactive monoterpene diselenides derived from menthane, carane, pinane, and bornane systems have been obtained. The influence of the terpene fragment of the obtained diselenides on the diastereomeric excess of the methoxyselenylation
Selenocyclization with the use of the monoterpene diselenides from menthane, carane and pinane groups has been studied. The conditions for asymmetric selenocyclization have been optimized. It has been established that the best enantiomeric excesses were obtained in the case of selenocyclization for the unsubstituted alkyl diselenides with (+)-dineomenthyl diselenide. The results of the selenocyclization of the (+)-dineomenthyl diselenide with the unsaturated alcohols and acids are presented. (C) 2007 Elsevier Ltd. All rights reserved.