Phenanthrene synthesis via chromium-catalyzed annulation of 2-biaryl grignard reagents and alkynes

• Main Authors: Yan, Jianming, Yoshikai, Naohiko
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2019
• Subjects: Grignard Reagents; Phenanthrene Synthesis; DRNTU::Science::Chemistry
• Online Access: https://hdl.handle.net/10356/90303; http://hdl.handle.net/10220/48492
• Institution: Nanyang Technological University

A chromium/2,2′-bipyridine-catalyzed annulation reaction of 2-biarylmagnesium reagents with alkynes is reported. The reaction is applicable to a variety of aryl- and/or alkyl-substituted internal alkynes as well as 2-biaryl and related Grignard reagents, thus affording phenanthrene derivatives in moderate to good yields. The reaction proceeds at the expense of excess alkyne as a hydrogen acceptor and thus does not need an external oxidant. Deuterium-labeling experiments shed light on the reaction mechanism, which likely involves multiple intramolecular C–H activation processes on chromium.