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Controlling Regioselectivity in Palladium‐Catalyzed C−H Activation/Aryl–Aryl Coupling of 4‐Phenylamino[2.2]paracyclophane
Author(s) -
Zippel Christoph,
Spuling Eduard,
Hassan Zahid,
Polamo Mika,
Nieger Martin,
Bräse Stefan
Publication year - 2020
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.202003709
Subject(s) - aryl , amination , chemistry , regioselectivity , palladium , selectivity , catalysis , reactivity (psychology) , combinatorial chemistry , coupling reaction , stereochemistry , medicinal chemistry , organic chemistry , alkyl , medicine , alternative medicine , pathology
Selective activation/functionalization of C−H bonds has emerged as an atom‐ and step‐economical process at the forefront of modern synthetic chemistry. This work reports palladium‐catalyzed exclusively para ‐selective C−H activation/aryl–aryl bond formation with a preference over N ‐arylation under the Buchwald–Hartwig amination reaction of 4‐phenylamino[2.2]paracyclophane. This innovative synthetic strategy allows a facile preparation of [2.2]paracyclophane derivatives featuring disparate para ‐substitutions at C‐4 and C‐7 positions in a highly selective manner, gives access to a series of potential candidates for [2.2]paracyclophane‐derived new planar chiral ligands. The unprecedented behavior in reactivity and preferential selectivity of C−C coupling over C−N bond formation via C−H activation is unique to the [2.2]paracyclophane scaffold compared to the non‐cyclophane analogue under the same reaction conditions. Selective C−H activation/aryl–aryl bond formation and sequential C−N coupling product formation is evidenced unambiguously by X‐ray crystallography.