Regioselective construction of 2-substituted indolines enabled by a rhodium-catalyzed decarboxylation-hydroacylation sequence

Herein, we describe the first rhodium(i)-catalyzed decarboxylative cyclization and hydroacylation of vinyl benzoxazinanones with chelating aldehydes, allowing a straightforward and efficient synthesis of 2-substituted indolines in moderate to good yields with excellent regioselectivity. Of note, the mechanistic proposal indicates that a new intermediate featuring eta 2-coordination may be in situ generated through a nucleophilic attack at the central carbon of the pi-allylmetal intermediate followed by reductive elimination. This study provides unique insights into the reactivity of pi-allylmetal species that can be used in hydrofunctionalization. Rhodium(i)-catalyzed sequential decarboxylation and hydroacylation of vinyl benzoxazinanones with chelating aldehydes for the highly regioselective synthesis of 2-substituted indolines via a new eta 2-Rh complex has been developed.