Ligand Control of Regioselectivity in Palladium-Catalyzed Heteroannulation Reactions of 1,3-Dienes

Abstract

Olefin carbofunctionalization reactions are indispensable tools for constructing diverse, functionalized scaffolds from simple starting materials. However, achieving precise control over regioselectivity in intermolecular reactions remains a formidable challenge. By using PAd2nBu as a ligand, we have achieved regioselective heteroannulation of o-bromoanilines with branched 1,3-dienes through ligand control. This enables regiodivergent access to 3-substituted indolines, showcasing excellent regioselectivity and reactivity across a range of functionalized substrates. To gain further insights into the origin of selectivity control, we employed a data-driven strategy, developing a linear regression model using calculated parameters for phosphorus ligands. This model identified four key parameters governing regioselectivity in this transformation, paving the way for future methodology development. Additionally, density functional theory calculations elucidated key selectivity-determining transition structures along the reaction pathway, corroborating our experimental observations and establishing a solid foundation for future advancements in regioselective olefin difunctionalization reactions.