2‐Pyridyl Sulfoxide: A Versatile and Removable Directing Group for the Pd
<sup>II</sup>
‐Catalyzed Direct CH Olefination of Arenes
作者:Alfonso García‐Rubia、M. Ángeles Fernández‐Ibáñez、Ramón Gómez Arrayás、Juan Carlos Carretero
DOI:10.1002/chem.201003633
日期:2011.3.21
Removable and versatile: The 2‐pyridylsulfinyl group has proved to be an efficient directinggroup in the PdII‐catalyzed aryl ortho CH olefination. This catalyst system enables the sequential double olefination to give asymmetrically di‐ortho‐functionalized arenes. The sulfinyl directinggroup can be easily cleaved, providing access to 1,3‐disubstituted arenes, or transformed into a thiol group.
Ni-catalyzed C–S bond cleavage of aryl 2-pyridyl thioethers coupling with alkyl and aryl thiols
作者:Cheng-Yi Wang、Rui Tian、Yong-Ming Zhu
DOI:10.1016/j.tet.2021.132453
日期:2021.10
A nickel-catalyzed C–SPy bond activation reactions to produce a variety of thioethers has been developed. The reaction is promoted by a user-friendly, inexpensive, air and moisture-stable Ni precatalyst. Various aryl 2-pyridyl thioethers and a wide range of alkyl and aryl thiols substrates were tolerated in this process which afforded products in moderate to excellent yields.
Palladium-catalyzed C–H activation reactions directed by a removable 2-pyridylsulfinyl group were developed. Aromatic olefination products were formed in good yields on treatment of 2-(phenylsulfinyl)pyridines with alkenes in the presence of a Pd catalyst. The reaction tolerates a wide range of substituted alkenes, including various acrylates and styrenes. The controlled experiments indicated that
nanoparticles efficiently catalyzed the C–S cross coupling of aryl and alkyl thiols with aryl halides in the absence of ligands on water under mild conditions. A wide range of diaryl sulfides and aryl alkyl sulfides are synthesized in good to excellent yields utilizing this protocol. This procedure is particularly noteworthy given its mild conditions, avoiding the undesired formation of disulfides through
constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six‐ and five‐membered 2‐chloroheteroarenes (i.e., functionalized