Open Access1-Aminopyridinium Ylides as Monodentate Directing Groups for sp3 C–H Bond Functionalization
Author(s) -
Ky Khac Anh Le,
Hanh Nho Nguyen,
Olafs Daugulis
Publication year - 2019
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.9b06643
Subject(s) - chemistry , surface modification , moiety , pyridine , denticity , methylene , reactivity (psychology) , alkylation , medicinal chemistry , palladium , stereochemistry , catalysis , organic chemistry , crystal structure , medicine , alternative medicine , pathology
1-Aminopyridinium ylides are efficient directing groups for palladium-catalyzed β-arylation and alkylation of sp 3 C-H bonds in carboxylic acid derivatives. The efficiency of these directing groups depends on the substitution at the pyridine moiety. The unsubstituted pyridine-derived ylides allow functionalization of primary C-H bonds, while methylene groups are unreactive in the absence of external ligands. 4-Pyrrolidinopyridine-containing ylides are capable of C-H functionalization in acyclic methylene groups in the absence of external ligands, thus rivaling the efficiency of the aminoquinoline directing group. Preliminary mechanistic studies have been performed. A cyclopalladated intermediate has been isolated and characterized by X-ray crystallography, and its reactivity was studied.