Experimental and computational studies on the palladium-catalyzed intramolecular dearomatization, electrophilic addition, intermolecular coupling sequence

Abstract

An unprecedented Pd-catalyzed highly stereoselective synthetic strategy for the construction of a broad spectrum of polycyclic fused indoline skeletons employing N-halobenzoyl o-haloanilines and N-(prop-2-yn-1-yl)anilines as substrates in the presence of Pd(PPh₃)₄ (10 mol%), Cu₂O (20 mol%), BINOL-based phosphoramidite L (12 mol%), and K₂CO₃ (2.0 equiv.) in 1,2-dichloroethane at 110 °C for 19 h under an argon atmosphere has been described. This palladium-catalyzed protocol, which proceeds through sequential intramolecular dearomative Heck annulation/phenyl electrophilic addition/dehydrogenation sequences, provides a straightforward, powerful, and atom-economical approach for accessing elaborated indoline quinoline derivatives in moderate-to-good yields.