Palladium-catalyzed desulfitative arylation of azoles with arylsulfonyl hydrazides
作者:Xinzhang Yu、Xingwei Li、Boshun Wan
DOI:10.1039/c2ob26270c
日期:——
Palladium-catalyzed desulfitative and denitrogenative arylation of azoles with arylsulfonylhydrazides has been achieved. A broad scope of azoles and arylsulfonylhydrazides has been used to produce arylated azoles in high yields.
A Ni‐catalyzed C−F bond functionalization of unactivated arylfluorides with oxazoles as coupling partners was developed. Various arylated oxazoles could be obtained in moderate to good yields in the presence of Ni(cod)2/IMes catalytic system. A rapid synthesis of natural product texaline was also demonstrated using this protocol. This transformation could be potentially utilized in regioselective
Reaction of Alkynes and Azides: Not Triazoles Through Copper-Acetylides but Oxazoles Through Copper-Nitrene Intermediates
作者:Estela Haldón、Maria Besora、Israel Cano、Xacobe C. Cambeiro、Miquel A. Pericàs、Feliu Maseras、M. Carmen Nicasio、Pedro J. Pérez
DOI:10.1002/chem.201303737
日期:2014.3.17
Well‐defined copper(I) complexes of composition [Tpm*,BrCu(NCMe)]BF4 (Tpm*,Br=tris(3,5‐dimethyl‐4‐bromo‐pyrazolyl)methane) or [Tpa*Cu]PF6 (Tpa*=tris(3,5‐dimethyl‐pyrazolylmethyl)amine) catalyze the formation of 2,5‐disubstituted oxazoles from carbonyl azides and terminal alkynes in a direct manner. This process represents a novel procedure for the synthesis of this valuable heterocycle from readily
photoannulation of α-azidochalcones into 2,5-diaryloxazoles was developed. The carbon–carbondouble bond of α-azidochalcone was cleaved, leading to the formation of new C–O and C–N bonds in the photoannulation. Control experiments were carried out, and a plausible mechanism of the photoannulation was proposed. The scope of the reaction was studied by synthesizing a series of 2,5-diaryloxazoles including two