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.
Acknowledgements
Financial support of this work by the Research Activity Council at The University of Alabama and assistance with the NMR experiments reported herein by Dr. Kenneth Belmore are gratefully acknowledged.