ABSTRACT
The dimethylated phenanthrenes 2,3-dimethylphenanthrene (4a), 2,7-dimethylphenanthrene (4b), 2,6-dimethylphenanthrene (4c) and 1,7-dimethylphenanthrene (4d) have been prepared in gram-quantities by a short sequence of directed ortho metalation (DoM) of N,N-diethylbenzamides followed by Suzuki–Miyaura cross-coupling reaction and directed remote metalation (DreM) to form 9-phenanthrols. The final phenanthrenes were obtained through protection/deprotection as triflates.
Acknowledgments
We want to thank Dr. Bjarte Holmelid at the University of Bergen and Jostein A. Johansen at the Artic University of Norway for doing our HRMS analyses, and Dr. Linus Malmquist and Professor Jan H. Christensen at the University of Copenhagen for fruitful collaboration.