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Sustainable Ligand‐Free, Palladium‐Catalyzed Suzuki–Miyaura Reactions in Water: Insights into the Role of Base
Author(s) -
Wang Yanyan,
Liu Yuanyuan,
Zhang Weiqiang,
Sun Huaming,
Zhang Kan,
Jian Yajun,
Gu Quan,
Zhang Guofang,
Li Jiyang,
Gao Ziwei
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902853
Subject(s) - catalysis , chemistry , palladium , ligand (biochemistry) , combinatorial chemistry , base (topology) , filtration (mathematics) , organic chemistry , mathematical analysis , biochemistry , statistics , receptor , mathematics
A simple and efficient system was developed for the ligand‐free Pd‐catalyzed Suzuki–Miyaura reaction in water under mild conditions. Quaternary ammonium hydroxides with long chains were found to be very suitable bases. This ligand‐free Pd‐catalyzed Suzuki–Miyaura reaction showed improved durability in water with Pd loadings decreased to ppm level. Bases were shown to stabilize active palladium species in addition to acting as a base during the catalytic process. In the catalytic system with a strong base, the soluble active Pd II ion exhibited anti‐reduction properties, which prevented aggregation and deactivation of Pd species. The entire catalytic system could be recycled after separating the product by simple filtration. The water‐compatible and air‐stable effective catalytic protocol described herein represents an attractive and green synthetic advance in Suzuki–Miyaura couplings.