798553-21-6Relevant articles and documents
Dynamic Kinetic Cross-Electrophile Arylation of Benzyl Alcohols by Nickel Catalysis
Guo, Peng,Wang, Ke,Jin, Wen-Jie,Xie, Hao,Qi, Liangliang,Liu, Xue-Yuan,Shu, Xing-Zhong
supporting information, p. 513 - 523 (2021/01/12)
Catalytic transformation of alcohols via metal-catalyzed cross-coupling reactions is very important, but it typically relies on a multistep procedure. We here report a dynamic kinetic cross-coupling approach for the direct functionalization of alcohols. The feasibility of this strategy is demonstrated by a nickel-catalyzed cross-electrophile arylation reaction of benzyl alcohols with (hetero)aryl electrophiles. The reaction proceeds with a broad substrate scope of both coupling partners. The electron-rich, electron-poor, and ortho-/meta-/para-substituted (hetero)aryl electrophiles (e.g., Ar-OTf, Ar-I, Ar-Br, and inert Ar-Cl) all coupled well. Most of the functionalities, including aldehyde, ketone, amide, ester, nitrile, sulfone, furan, thiophene, benzothiophene, pyridine, quinolone, Ar-SiMe3, Ar-Bpin, and Ar-SnBu3, were tolerated. The dynamic nature of this method enables the direct arylation of benzylic alcohol in the presence of various nucleophilic groups, including nonactivated primary/secondary/tertiary alcohols, phenols, and free indoles. It thus offers a robust alternative to existing methods for the precise construction of diarylmethanes. The synthetic utility of the method was demonstrated by a concise synthesis of biologically active molecules and by its application to peptide modification and conjugation. Preliminary mechanistic studies revealed that the reaction of in situ formed benzyl oxalates with nickel, possibly via a radical process, is an initial step in the reaction with aryl electrophiles.
Light-Induced Gold-Catalyzed Hiyama Arylation: A Coupling Access to Biarylboronates
Xie, Jin,Sekine, Kohei,Witzel, Sina,Kr?mer, Petra,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 16648 - 16653 (2018/12/04)
Organoboron compounds are versatile synthetic building blocks. We herein report a new strategy, a photochemical gold-catalyzed chemo-selective Hiyama arylation of B,Si bifunctionalized reagents with diazonium salts, which is orthogonal to common strategies and therefore a unique tool for synthesis of valuable biarylboronates. With this new methodology a wide array of diversely functionalized sp2- and sp3-hybridized biarylboronates were obtained. Notably, the synergism of gold catalysis with copper catalysis or palladium catalysis, allows for one-pot iterative C?X (heteroatom) and C?C couplings for the rapid assembly of several simple fragments to relatively complex molecules. Mechanistic studies indicated that photosensitizer-free conditions were superior to gold/Ru(bpy)3Cl2 dual catalysis.
Gold-catalyzed oxidative coupling reactions with aryltrimethylsilanes
Brenzovich Jr., William E.,Brazeau, Jean-Francois,Toste, F. Dean
supporting information; experimental part, p. 4728 - 4731 (2010/12/25)
During continuing studies with a novel oxidative gold oxyarylation reaction, arylsilanes were found to be competent coupling partners, providing further evidence for an intramolecular electrophilic aromatic substitution mechanism. While providing yields complementary to those of the previously described boronic acid methods, the use of trimethylsilanes reduces the observation of homocoupling byproducts and allows for facile intramolecular coupling reactions.
