Synthesis of Carbazoles and Dibenzofurans via Cross-Coupling of o-Iodoanilines and o-Iodophenols with Silylaryl Triflates
Zhijian Liu and Richard C. Larock*
*Department of Chemistry, Iowa State University, Ames, Iowa 50011, Email:
larock
iastate.edu
Z. Liu, R. C. Larock, Org. Lett., 2004, 6, 3739-3741.
DOI: 10.1021/ol048564l
Abstract
An efficient route to carbazoles and dibenzofurans has been developed. The reaction of o-iodoanilines or o-iodophenols with silylaryl triflates in the presence of CsF to afford N- or O-arylated products is followed by a cyclization using a Pd catalyst to carbazoles and dibenzofurans in good to excellent yields. Various functional groups are tolerated.
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Details
The document describes a novel and efficient method for synthesizing carbazoles and dibenzofurans through the cross-coupling of o-iodoanilines or o-iodophenols with silylaryl triflates, followed by palladium-catalyzed cyclization. This two-step, one-pot procedure yields N- or O-arylated products, which are then cyclized to form the desired heteroaromatic compounds in good to excellent yields. The method tolerates various functional groups and uses commercially available or easily synthesized starting materials. The process involves reacting the aryl iodide with silylaryl triflate and CsF in acetonitrile at room temperature, followed by the addition of Pd(OAc)2 and PCy3 and heating at 100°C. The study highlights the versatility and efficiency of this approach, which overcomes limitations of existing methods, such as multiple steps, low yields, and harsh conditions. The synthesized carbazoles and dibenzofurans have significant applications in biological activities, electroluminescent materials, and organic light-emitting diodes. The research was supported by the Petroleum Research Fund and involved detailed experimental procedures and characterization data, available online. Further studies are ongoing to explore the scope and limitations of this synthetic method.
Key Words
Carbazoles, Dibenzofurans, Pd Catalysis
ID: J54-Y2004-940
