Controllable Rh(III)-Catalyzed Annulation between Salicylaldehydes and Diazo Compounds: Divergent Synthesis of Chromones and Benzofurans
作者:Peng Sun、Shang Gao、Chi Yang、Songjin Guo、Aijun Lin、Hequan Yao
DOI:10.1021/acs.orglett.6b03355
日期:2016.12.16
A Rh(III)-catalyzed annulation between salicylaldehydes and diazocompounds with controllable chemoselectivity is described. AgNTf2 favored benzofurans via a tandem C–H activation/decarbonylation/annulation process, while AcOH led to chromones through a C–H activation/annulation pathway. The reaction exhibited good functional group tolerance and scalability. Moreover, only a single regioisomer of benzofuran
Cp*Ir(III)-Catalyzed C–H/O–H Functionalization of Salicylaldehydes for the Synthesis of Chromones at Room Temperature
作者:Dhanaji M. Lade、Yogesh N. Aher、Amit B. Pawar
DOI:10.1021/acs.joc.9b01139
日期:2019.7.19
C–H/O–H-bond functionalization of salicylaldehydes with α-diazocarbonyl compounds for the synthesis of chromones under redox-neutral conditions. The reaction proceeds at roomtemperature and displays excellent functional group tolerance along with high yields of the corresponding products. The developed reaction protocol was successfully applied for the late-stage functionalization of estrone derivative
3-Disubstituted benzofurans were synthesized from acrolein dimer and 1,3-dicarbonyl compounds by using N-bromosuccinimide as an oxidizing agent. The method was used to synthesize two commercial drug molecules, benzbromarone and amiodarone. The proposed mechanism of the reaction involves a N-bromosuccinimide (NBS)-assisted autotandem catalysis with Lewis acid catalyst. To proof the proposed mechanism
Pd-catalyzed intramolecular Heck reaction for the synthesis of 2-methylbenzofurans
作者:Lixin Zhou、Yuxing Shi、Xueyan Zhu、Peng Zhang
DOI:10.1016/j.tetlet.2019.06.054
日期:2019.7
A new strategy for the synthesis of 2-Methylbenzofurans via the intramolecular Heckreaction has been developed. This efficient palladium-catalyzed system showed good catalytic activity. Various substituted 2-methylbenzofurans could be afforded in good to excellent yields.
<i>De novo</i> synthesis of benzofurans <i>via</i> trifluoroacetic acid catalyzed cyclization/oxidative aromatization cascade reaction of 2-hydroxy-1,4-diones
作者:Qiang Sha、Haixuan Liu
DOI:10.1039/c9ob01422e
日期:——
for the de novo synthesis of benzofurans from 2-hydroxy-1,4-diones is described. Using trifluoroacetic acid (TFA) as the catalyst and N-bromobutanimide (NBS) as the oxidant, 2-hydroxy-1,4-diones underwent a cyclization/oxidative aromatization cascade reaction to afford a variety of benzofuran derivatives in moderate to good yields. This is a practically useful method for the synthesis of benzofuran derivatives