Palladium catalyzed annulation of 2-iodobiphenyl with a non-terminal alkene enabled by neighboring group assistance

In this work, an efficient palladium catalyzed annulation of 2-iodobiphenyl with a non-terminal alkene was developed. The key factor in this transformation was the formation of a highly reactive oxo-palladacycle intermediate, which was enabled by a neighboring hydroxyl group, and remarkably restrained the beta-H elimination process. Mechanistically, control experiments demonstrated that the hydroxyl group may act as an anionic ligand, which was irreplaceable in this reaction. This transformation presented good reactivity and selectivity, and no simple Heck coupling products were detected for all of the explored substrates.

Automated summary

An efficient palladium-catalyzed annulation of 2-iodobiphenyl with a non-terminal alkene was developed, with the key factor being the formation of a highly reactive oxo-palladacycle intermediate enabled by a neighboring hydroxyl group, which significantly restrained the beta-H elimination process. Mechanistic studies showed that the hydroxyl group may act as an anionic ligand, essential for this transformation, which exhibited good reactivity and selectivity without detection of simple Heck coupling products for all explored substrates.