We have developed a new and general approach to construct a variety of benzo[b]fluorene and cyclopenta-[b]naphthalene derivatives via the palladium(0)/copper(I)-catalyzed tandem cyclization of aryl 1-cyanoalk-5-ynyl ketone systems in an extremely efficient manner. The key operation lies in the copper(I)-catalyzed aerobic oxidation, which allows for activation of two successive intramolecular cycloadditions immediately after the Sonogashira coupling reaction has occurred.
Date:
2013-04
Relation:
Advanced Synthesis and Catalysis. 2013 Apr;355(7):1323-1337.