Nickel-Catalyzed Ring-Opening C-O Functionalization of peri-Xanthenoxanthenes for 8-Substituted Binaphthol Synthesis.

ABSTRACT

Herein, we disclose the Ni-catalyzed ring-opening C-O functionalization of peri-xanthenoxanthenes using Grignard reagents that forms 8-monofunctionalized binaphthols. 1,2-Bis(dicyclohexylphosphino)ethane was the best ligand for alkylations and ICy for arylation. After mechanistic investigations, we assumed that the reaction proceeds via C-O reduction and subsequent C-O functionalization. To verify the mechanism, the intermediate after reduction was isolated. Moreover, the asymmetric addition, using 8-octylbinaphthol after optical resolution, was studied.