Directed Metalation–Suzuki–Miyaura Cross-Coupling Strategies: Regioselective Synthesis of Hydroxylated 1‑Methyl-phenanthrenes
journal contributionposted on 02.10.2015, 00:00 by Kåre B. Jørgensen, Toni Rantanen, Thilo Dörfler, Victor Snieckus
A general, efficient, and regioselective synthesis of a series of hydroxylated 1-methylphenanthrenes 9 by a combined directed ortho metalation (DoM)–Suzuki–Miyaura cross-coupling–directed remote metalation (DreM) sequence is reported. Diversity to this methodology was achieved by a regioselective DoM rather than DreM reaction, affording more highly substituted phenanthrols (Table ). Application of the turbo-Grignard reagent (i-PrMgCl·LiCl) in the Ni-catalyzed Corriu–Kumada reaction gave efficient decarbamoylation (Tables and ). Additional features are the TMS protecting group and halo-induced ipso-desilylation tactics applied to the regioselective synthesis of phenanthrenes (Scheme ).