Concise Synthesis of Polycyclic Indoline Scaffolds through an In ^{IIIIII ‐Catalyzed Formal [4+2] Annulation of 2,3‐Disubstituted Indoles with oo ‐Aminobenzyl Alcohols}

摘要

> A concise indium(III)‐catalyzed annulation of 2,3‐disubstituted indoles with o ‐aminobenzyl alcohols is reported. The in situ generated aza‐ ortho ‐quinone methides (aza‐ o QMs) were efficiently trapped by diverse carbazoles in a formal [4+2] cycloaddition reaction catalyzed by indium(III) triflate, which provided rapid access to bridged polycyclic indoline alkaloid skeletons.