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Pd 0 ‐Catalyzed Coupling Cyclization Reaction of Aryl or 1Alkenyl Halides with 1,2‐Allenyl Ketones: Scope and Mechanism. An Efficient Assembly of 2,3,4‐, 2,3,5‐Tri‐ and 2,3,4,5‐Tetrasubstituted Furans
Author(s) -
Ma Shengming,
Zhang Junliang,
Lu Lianghua
Publication year - 2003
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.200204664
Subject(s) - chemistry , nucleophile , aryl , catalysis , substituent , medicinal chemistry , palladium , deuterium , halide , intramolecular force , reaction mechanism , stereochemistry , organic chemistry , physics , quantum mechanics , alkyl
Abstract Described herein is the Pd 0 ‐catalyzed coupling cyclization reaction of 1,2‐allenyl ketones with organic halides leading efficiently and conveniently to not only 2,3,4‐ and 2,3,5‐trisubstituted furans but also 2,3,4,5‐tetrasubstituted furans. Furthermore, this method showed high substituent‐loading capability and tolerance of various substituents. The reactions of 1,2‐allenyl ketones 1 e, 1 p, 1 q , and deuterated [D] 1 c were performed for a mechanistic study, which demonstrated that instead of an enolization pathway, the reaction may proceed via the intermediacy of dienolate palladium and intramolecular nucleophilic attack on the π‐allyl palladium intermediate by the carbonyl oxygen.