Pd-Catalyzed Cascade Intramolecular Heck Cyclization/Dearomatization of Indoles for the Construction of Two All-Carbon Quaternary Centers

Org Lett. 2022 Dec 9;24(48):8880-8885. doi: 10.1021/acs.orglett.2c03691. Epub 2022 Nov 29.

Abstract

A facile Pd-catalyzed cascade of intramolecular Heck cyclization/alkylpalladium activated dearomatization of aryl alkyne-tethered indole is described. In this single step two nonadjacent all-carbon quaternary centers, two nitrogen-containing heterocycles, and three C(sp2)-C(sp3) bonds are efficiently furnished. These products could also undergo 5-to-6 ring migration-expansion reaction under Brønsted-acid conditions to transform into the benzo[c]carbazole skeletons.