Abstract
The first selective palladium-catalyzed phenylselenylation of aryl bromides using a tin-free phenylselenolate source is reported. High selectivity for the desired asymmetric diaryl selenide is achieved using a catalyst derived from palladium and a Josiphos-type ligand with (PhSe)2/NaBH4 as the phenylselenylating agent. Aryl bromides are phenylselenylated at 100°C using low catalyst loadings to give the desired asymmetric diaryl selenides in high yield and >95% selectivity. Phenylselenoborane adducts formed by the reduction of diphenyl diselenide with sodium borohydride are more selective phenylselenylating reagents than sodium phenylselenolate.