Regio- and stereospecific alkyl and alkynyl substitution reactions of epoxy selenides with organoaluminums via episelenonium ions

Regio- and stereospecific alkyl and alkynyl substitution reactions of epoxy selenides with organoaluminum reagents have been developed, which proceed via episelenonium ion intermediates to give the C2 alkyl substitution products with double inversion of the configuration and the C1 alkynyl substitution products with migration of the arylseleno group in high yields, respectively.