Isothiourea-Mediated One-Pot Synthesis of Functionalized Pyridines
摘要:
Acids to bases: The synthesis of 2,4,6-trisubstituted pyridines from (phenylthio)acetic acid and a range of α,β-unsaturated ketimines is reported. This process proceeds by intermolecular Michael addition/lactamization, thiophenol elimination, and N- to O-sulfonyl migration, giving 2-sulfonate-substituted pyridines which are readily derivatized to generate structural diversity.
A novel iron-mediated direct C–H arylation of quinones and pyridine analogues with arylboronic acids has been developed using dichloromethane and water as solvents at ambient temperature. FeS is employed and serves as an efficient catalyst. A detailed reaction mechanism is speculated and expounded.
Direct Arylation of Substituted Pyridines with Arylboronic Acids Catalyzed by Iron(II) Oxalate
作者:Yibo Huang、Dan Guan、Liang Wang
DOI:10.1002/cjoc.201400528
日期:2014.12
The directarylation of substitutedpyridines with several arylboronicacids has been developed. This transformation could proceed readily at ambient temperature using inexpensive reagents: iron(II) oxalate as a catalyst, potassium persulfate as a co‐oxidant, which can afford the arylated products in mild to good yields. The mechanism is presumed to proceed through a nucleophilic radical addition to
α-Halo carbonyls enable meta selective primary, secondary and tertiary C–H alkylations by ruthenium catalysis
作者:Andrew J. Paterson、Callum J. Heron、Claire L. McMullin、Mary F. Mahon、Neil J. Press、Christopher G. Frost
DOI:10.1039/c7ob01192j
日期:——
selective C–H alkylation of arenes is described using a wide range of α-halo carbonyls as coupling partners. Previously unreported primary alkylations with high meta selectivity have been enabled by this methodology whereas using straight chain alkyl halides affords ortho substituted products. Mechanistic analysis reveals an activation pathway whereby cyclometalation with a ruthenium(II) complex activates
Cp*Rh(<scp>iii</scp>) and Cp*Ir(<scp>iii</scp>)-catalysed redox-neutral C–H arylation with quinone diazides: quick and facile synthesis of arylated phenols
作者:Shang-Shi Zhang、Chun-Yong Jiang、Jia-Qiang Wu、Xu-Ge Liu、Qingjiang Li、Zhi-Shu Huang、Ding Li、Honggen Wang
DOI:10.1039/c5cc03187g
日期:——
Cp*Rh(iii)- and Cp*Ir(iii)-catalysed direct C–H arylation with quinone diazides provides a facile and redox-neutral access to arylated phenols.
Silver-Catalyzed Minisci Reactions Using Selectfluor as a Mild Oxidant
作者:Jordan D. Galloway、Duy N. Mai、Ryan D. Baxter
DOI:10.1021/acs.orglett.7b02706
日期:2017.11.3
A new method for silver-catalyzed Minisci reactions usingSelectfluor as a mild oxidant is reported. Heteroarenes and quinones both participate in radical C–H alkylation and arylation from a variety of carboxylic and boronic acid radical precursors. Several oxidatively sensitive and highly reactive radical species are successful, providing structures that are challenging to access by other means.