Design of optically active selenium reagents having a chiral tertiary amino group and their application to asymmetric inter- and intramolecular oxyselenenylations

A new class of chiral selenium reagents 4-7 was synthesized on the basis of strong intramolecular interaction between an electrophilic selenium and an optically modified tertiary amine (Se ... N interaction) would induce asymmetric induction in the reaction between the selenium reagent and olefins. When 7, which showed the most powerful asymmetric induction, was applied to asymmetric methoxyselenenylation of (E)-phenylpropene under optimum reaction conditions, the highest diastereomeric excess (d.e.) of the trans-addition product was obtained (97% d.e.). The same reaction conditions were employed in asymmetric methoxyselenenylation of various olefins (up to 97% d.e.) and also in asymmetric intramolecular oxyselenenylation of terminal olefins (up to 59% d.e.) and internal olefins (up to 98% d.e.). The results show that this class of selenium reagents with a strong Se ... N interaction is useful for asymmetric organic synthesis. (C) 1997, Elsevier Science Ltd.