Convergent synthesis of 6-substituted phenanthridines via anionic ring closure.
[reaction: see text] The addition of organometallic derivatives to the cyano group of 2-(2-fluorophenyl)benzonitrile followed by intramolecular nucleophilic substitution produces 6-substituted phenanthridines. Alkyllithiums, aryllithiums, and sterically nondemanding lithium amides reacted at -78 degrees C to produce the 6-substituted phenanthridines in 82-98% yield upon warming to room temperature. The addition of the corresponding Grignard reagents requires an excess of the organometallic reagent and extented reaction times at elevated temperature.
Lysén
Morten
M
The Royal Danish School of Pharmacy, Department of Medicinal Chemistry, Universitetsparken 2, DK-2100, Copenhagen, Denmark.
Kristensen
Jesper L
JL
Vedsø
Per
P
Begtrup
Mikael
M