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Double CH Functionalization in Sequential Order: Direct Synthesis of Polycyclic Compounds by a Palladium‐Catalyzed CH Alkenylation–Arylation Cascade
Author(s) -
Ohno Hiroaki,
Iuchi Mutsumi,
Kojima Naoto,
Yoshimitsu Takehiko,
Fujii Nobutaka,
Tanaka Tetsuaki
Publication year - 2012
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.201103819
Subject(s) - cascade , palladium , surface modification , catalysis , combinatorial chemistry , chemistry , organic chemistry , chromatography
Abstract Palladium‐catalyzed cascade CH alkenylation and arylation provides convenient access to polycyclic aromatic compounds. Treatment of 3‐bromoaniline derivatives bearing a bromocinnamyl group on the nitrogen atom with a catalytic amount of [Pd(OAc) 2 ] and PCy 3 ⋅HBF 4 in the presence of Cs 2 CO 3 in dioxane affords naphthalene‐fused indole derivatives in good yields. This double cyclization reaction is also applicable to heterocyclic substrates, giving fused indoles containing a heteroaromatic ring such as dibenzofuran, dibenzothiophene, carbazole, indole, or benzofuran through heterocyclic CH arylation. When using a 2,6‐unsubstituted aniline derivative, the first CH arylation preferentially proceeds at the more hindered position of the aniline ring.