Merging Visible-Light Photocatalysis and Palladium Catalysis for C−H Acylation of Azo- and Azoxybenzenes with α-Keto Acids
作者:Ning Xu、Pinhua Li、Zuguang Xie、Lei Wang
DOI:10.1002/chem.201504530
日期:2016.2.12
efficient C−H acylation of azo‐ and azoxybenzenes with α‐keto acids has been developed by a combination of palladium catalysis and visible‐light photoredox catalysis at room temperature under 1.5 W blue LED irradiation. This method tolerates a variety of disubstituted azo‐ and azoxybenzenes, as well as α‐keto acids regardless of the nature of the substituents. A number of aryl ketones were obtained
Palladium-catalyzed direct ortho-ethoxycarbonylation of azobenzenes and azoxybenzenes with diethyl azodicarboxylate
作者:Ning Xu、Dengke Li、Yicheng Zhang、Lei Wang
DOI:10.1039/c5ob01264c
日期:——
A palladium-catalyzed direct ortho-ethoxycarbonylation of azobenzenes and azoxybenzenes with diethyl azodicarboxylate (DEAD) was developed under mild reaction conditions.
Synthesis of (2
<i>H</i>
)‐Indazoles from Azobenzenes Using Paraformaldehyde as a One‐Carbon Synthon
作者:Rina Chun、Saegun Kim、Sang Hoon Han、Sangil Han、Suk Hun Lee、Neeraj Kumar Mishra、Young Hoon Jung、Hyung Sik Kim、In Su Kim
DOI:10.1002/adsc.201801547
日期:2019.4
hydroxymethylation followed by intramolecular annulation of azobenzenesusingparaformaldehyde as a valuable C1‐feedstock is described. The method is readily extended to the coupling reaction between azobenzenes and trifluoroacetaldehyde. This transformation efficiently produces a range of C3‐unsubstituted and C3‐trifluoromethylated (2H)‐indazoles, which are important targets in the development of novel
A Unique Alkylation of Azobenzenes with Allyl Acetates by Rh<sup>III</sup>-Catalyzed C–H Functionalization
作者:Hong Deng、Hongji Li、Lei Wang
DOI:10.1021/acs.orglett.5b00957
日期:2015.5.15
A novel RhIII-catalyzed direct alkylation of azobenzenes with allylacetates through C–H activation and functionalization is demonstrated in which the allylacetates serve as unique alkylation agents. The rhodium-catalyzed alkylation provides a highly efficient and atom-economic approach to a series of azo compounds.
A process is described for preparing isoxazoles of the formula I
where the substituents are as defined below:
R
1
is hydrogen, C
1
-C
6
-alkyl,
R
2
is C
1
-C
6
-alkyl,
R
3
, R
4
, R
5
are hydrogen, C
1
-C
6
-alkyl, or R
4
and R
5
together form a bond,
R
6
is a heterocyclic ring,
n is 0, 1 or
2;
which comprises preparing an intermediate of the formula VI
where R1, R3, R4 and R5 are as defined above, followed by halogenation, thiomethylation, oxidation and acylation to give compounds of the formula I. Also novel intermediates for preparing the compounds of the formula I and novel processes for preparing the intermediates are described.