Urea Ligand-Promoted Chainwalking Heteroannulation for the Synthesis of 6- and 7-membered Azaheterocycles.

Typical approaches to heterocycle construction require significant changes in synthetic strategy even for a change as minor as increasing the ring size. The ability to access multiple heterocyclic scaffolds through a common synthetic approach, simply through trivial modification of one reaction component, would enable facile access to diverse libraries of structural analogues of core scaffolds. Here, we show that urea-derived ligands effectively promote Pd-mediated chainwalking processes to enable remote heteroannulation for the rapid construction of six- and seven-membered azaheterocycles under essentially identical reaction conditions.

Convergent Synthesis of Dihydrobenzofurans via Urea Ligand-Enabled Heteroannulation of 2-Bromophenols with 1,3-Dienes.

We disclose a palladium and urea ligand-mediated heteroannulation of 2-bromophenols and 1,3-dienes. This method addresses synthetic challenges present in the palladium-catalyzed heteroannulation of bifunctional reagents and olefins by engaging a diverse scope of coupling partners under a unified set of reaction conditions. Our recently developed urea ligand platform outperforms phosphine ligands to generate the dihydrobenzofuran motif in a convergent manner.