Synthesis of Fluoren-9-ones via Palladium-Catalyzed Cyclocarbonylation of o-Halobiaryls
摘要:
[GRAPHICS]The synthesis of various substituted fluoren-9-ones has been accomplished by a novel palladium catalyzed cyclocarbonylation of o-halobiaryls. The cyclocarbonylation of 4'-substituted-2-iodobiphenyls produces very high yields of 2-substituted fluoren-9-ones bearing either electron donating or electron-withdrawing substituents. 3'-Substituted 2-iodobiphenyls afford in excellent yields with good regioselectivity 3-substituted fluoren-9-ones. This chemistry has been successfully extended to polycyclic and heterocyclic fluorenones.
[reaction: see text] Reaction of 2,2'-dihalobiphenyl with butyllithium followed by the addition of chromium(III) chloride and alkynes afforded the corresponding phenanthrene derivativesvia formal [4 + 2] cycloaddition. A variety of alkynes could be used for this reaction, such as alkyl, aryl, silyl, and alkoxycarbonyl alkynes. Repetitive process of the reaction gave more extended polycyclic compounds
2-Arylbenzoylchlorides undergo annulativecoupling with internal alkynes in the presence of a catalyst system of [IrCl(cod)]2/P(t-Bu)3 to selectively afford the corresponding phenanthrenederivatives accompanied by elimination of carbon monoxide and hydrogen chloride. The reaction occurs without addition of any external base. Deuterium-labeling experiments using 2-(d5-phenyl)benzoyl chloride suggest
Synthesis of Fluoren-9-ones via Palladium-Catalyzed Cyclocarbonylation of <i>o</i>-Halobiaryls
作者:Marino A. Campo、Richard C. Larock
DOI:10.1021/ol006585j
日期:2000.11.1
[GRAPHICS]The synthesis of various substituted fluoren-9-ones has been accomplished by a novel palladium catalyzed cyclocarbonylation of o-halobiaryls. The cyclocarbonylation of 4'-substituted-2-iodobiphenyls produces very high yields of 2-substituted fluoren-9-ones bearing either electron donating or electron-withdrawing substituents. 3'-Substituted 2-iodobiphenyls afford in excellent yields with good regioselectivity 3-substituted fluoren-9-ones. This chemistry has been successfully extended to polycyclic and heterocyclic fluorenones.