Premium
Unusual 1,2‐Aryl Migration and Depalladation of Alkylpalladium Intermediates Containing a syn ‐β‐Hydrogen Atom
Author(s) -
Youn So Won,
Lee So Ra,
Kim Yun Ah,
Kang Da Young,
Jang Min Jung
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201601382
Subject(s) - chemistry , aryl , nucleophile , reductive elimination , alkene , hydride , bond cleavage , medicinal chemistry , oxidative addition , hydrogen atom , catalysis , stereochemistry , cleavage (geology) , migratory insertion , hydrogen , organic chemistry , group (periodic table) , alkyl , geotechnical engineering , fracture (geology) , engineering
In general, alkylpalladium intermediates containing a syn β‐hydrogen atom are expected to undergo β–hydride elimination preferentially. However, this study unveils a new mechanistic mode in a Pd(II)‐catalyzed transformation, which leads to a series of both C−N/C−C bond forming and C−C bond forming/cleavage events. It has been demonstrated that a Pd(II)‐catalyzed oxidative cyclization of stilbenes bearing a pendent nucleophile such as 2‐alkenylanilines and 2‐alkenylphenyl 1,3‐diketones operates through an uncommon Pd−C bond cleavage assisted by a neighboring aryl group and CuCl 2 –assisted transient Pd oxidation, rather than generally preferred β–hydride elimination in alkylpalladium intermediates containing a syn β‐hydrogen atom. As a result, 1,2‐aryl migration occurs to lead to the unexpected formation of a variety of 3‐substituted indoles and 4‐aryl‐1‐naphthols. In addition, selective migration of an aryl group could be achieved from β,β‐disubstituted alkene substrates through alkylpalladium intermediates deprived of syn β‐hydrogen atom.