New Practical Synthesis of Indazoles via Condensation of o-Fluorobenzaldehydes and Their O-Methyloximes with Hydrazine
摘要:
The reaction of o-fluorobenzaldehydes and their O-methyloximes with hydrazine has been developed as a new practical synthesis of indazoles. Utilization of the methyloxime derivatives of benzaldehydes (in the form of the major E-isomers) in this condensation effectively eliminated a competitive Wolf-Kishner reduction to fluorotoluenes, which was observed in the direct preparations of indazoles from aldehydes. Reaction of Z-isomers of methyloximes with hydrazine resulted in the formation of 3-aminoindazoles via a benzonitrile intermediate.
A denitrogenative palladium-catalyzed cascade for regioselective synthesis of fluorenes
作者:Wai Chung Fu、Fuk Yee Kwong
DOI:10.1039/c9sc04062e
日期:——
cascade for the modular and regioselective synthesis of polysubstituted fluorenes. Hydrazone facilitates the Pd(II) to Pd(IV) oxidative addition in a Catellani pathway and is also the methylene synthon in the proposed reaction. Aryl iodides and 2-bromoarylaldehyde hydrazones undergo a norbornene-controlled tandem reaction sequence to give a broad scope of fluorenes in the presence of a palladium catalyst