Chemo-, Diastereo-, and Enantioselective Iridium-Catalyzed Allylic Intramolecular Dearomatization Reaction of Naphthol Derivatives

• Published in: Angewandte Chemie International Edition Vol. 55; no. 10; pp. 3496 - 3499
• Main Authors: Cheng, Qiang, Wang, Ye, You, Shu-Li
• Format: Journal Article
• Language: English
• Published: WEINHEIM Blackwell Publishing Ltd 01.03.2016; Wiley; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: aromaticity; asymmetric catalysis; Catalysts; Chemistry; Chemistry, Multidisciplinary; Derivatives; Enantiomers; Iridium; ligand effects; Naphthol; Nuclei; Oxygen atoms; Physical Sciences; Science & Technology; Selectivity; spiro compounds; ASYMMETRIC DEAROMATIZATION; SUBSTITUTION; ARYLATIVE DEAROMATIZATION; ALKYLATION; ALLYLATION; PHOSPHORAMIDITE; asymmetric catalysis; spiro compounds; INDOLES; iridium; PHENOLS; CONSTRUCTION; STEREOGENIC CENTERS; aromaticity; ligand effects
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201511519

An iridium‐catalyzed intramolecular asymmetric allylic dearomatization reaction of naphthol derivatives is described. Challenges confronted in this reaction include chemoselectivity between carbon and oxygen atoms as nucleophilic centers, diastereoselectivity when contiguous chiral centers are generated, and enantioselective control for constructing an all‐carbon quaternary stereocenter. In the presence of an iridium catalyst generated from [{Ir(dbcot)Cl}2] (dbcot=dibenzocyclooctatetraene) and a new THQphos (tetrahydroquinolinedinaphthophosphoramidite) ligand, various spironaphthalenones were obtained with up to greater than 95:5 C/O selectivity, greater than 95:5 d.r., and 99 % ee, thus providing a general method for the dearomatization of naphthols. Triple challenge: The challenges addressed in the title reaction include chemoselectivity between C and O as nucleophiles, diastereoselectivity when contiguous chiral centers are generated, and enantioselective control for constructing an all‐carbon quaternary stereocenter. The [{Ir(dbcot)Cl}2]/(S,Sa)‐L system leads to a general method for the dearomatization of naphthols. dbcot=dibenzocyclooctatetraene.