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Palladium(0)‐Catalyzed Tandem Cyclization of Allenenes: Direct Construction of Tricyclic Heterocycles through Aromatic CH Activation
Author(s) -
Ohno Hiroaki,
Miyamura Kumiko,
Mizutani Tsuyoshi,
Kadoh Yoichi,
Takeoka Yusuke,
Hamaguchi Hisao,
Tanaka Tetsuaki
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500050
Subject(s) - chemistry , moiety , tandem , aryl , halide , palladium , substituent , catalysis , olefin fiber , intramolecular force , medicinal chemistry , potassium carbonate , electrophilic aromatic substitution , aryl halide , organic chemistry , combinatorial chemistry , alkyl , materials science , composite material
Palladium(0)‐catalyzed tandem cyclization of allenenes is described. Treatment of allenenes with an aryl halide, potassium carbonate, and catalytic [Pd(PPh 3 ) 4 ] in dioxane afforded tri‐ or tetracyclic heterocycles in moderate to good yields through insertion of arylpalladium( II ) halide into the allenic moiety, intramolecular carbopalladation, and aromatic CH bond activation. The substituent on the olefin terminus has proven to be essential for the success of the tandem cyclization. The reaction with heterocyclic aryl halides such as iodopyrazine or 4‐bromo‐1‐methylindole afforded tri‐ or tetracyclic heteroaromatic products in good yields.