Strategies towards potent trypanocidal drugs: Application of Rh-catalyzed [2 + 2 + 2] cycloadditions, sulfonyl phthalide annulation and nitroalkene reactions for the synthesis of substituted quinones and their evaluation against Trypanosoma cruzi
作者:James M. Wood、Nishikant S. Satam、Renata G. Almeida、Vinicius S. Cristani、Dênis P. de Lima、Luiza Dantas-Pereira、Kelly Salomão、Rubem F.S. Menna-Barreto、Irishi N.N. Namboothiri、John F. Bower、Eufrânio N. da Silva Júnior
DOI:10.1016/j.bmc.2020.115565
日期:2020.8
Rhodium-catalyzed [2 + 2 + 2] cycloadditions, sulfonyl phthalideannulations and nitroalkene reactions have been employed for the synthesis of 56 quinone-based compounds. These were evaluated against Trypanosoma cruzi, the parasite that causes Chagas disease. The reactions described here are part of a program that aims to utilize modern, versatile and efficient synthetic methods for the one or two
Highly Stereo- and Regioselective Hydrocarboxylation of Diynes with Carbon Dioxide
作者:Tao Cao、Shengming Ma
DOI:10.1021/acs.orglett.6b00028
日期:2016.4.1
A nickel-catalyzed three-component hydrocarboxylation of diynes with ZnEt2 and CO2 (1 atm) is disclosed. With this method, symmetric/nonsymmetric diynes could be reacted smoothly with very high stereo- and regioselectivity, affording conjugated 2,4-alkadienoic acids incorporated with five- or six-membered rings efficiently. A stepwise non-oxidative cyclometalation mechanism was proposed based on careful
the stereoselectivesynthesis of various (E)-, (Z)-, and disubstituted 3-alkylideneoxindoles via radical cyclization reactions were investigated using tandem indium-mediated carbometallation and palladium-catalyzed cross-couplingreactions. The proper combination of substrates and reaction conditions is important for good yields. The key step is the first stereoselective carboindation reaction using
Asymmetric Synthesis of Alkylzincs by Rhodium‐Catalyzed Enantioselective Arylative Cyclization of 1,6‐Enynes with Arylzincs
作者:Jiahua Chen、Tamio Hayashi
DOI:10.1002/anie.202008770
日期:2020.10.12
A chiral diene‐rhodium complex was found to catalyze the reaction of 1,6‐enynes with ArZnCl to give high yields of 2‐(alkylidene)cyclopentylmethylzincs with high enantioselectivity (95–99 % ee). The enantioenriched alkylzincs were readily converted in a one‐pot approach into a wide variety of functionalized products by taking advantage of their unique reactivity. The catalytic cylcle involves arylrhodation
2 + 1] cycloaddition takes place in the rhodium-catalyzed reaction of 1,6-enynes with borylsilanes bearing an alkoxy group on the silicon atoms, which react as synthetic equivalents of silylene. The reaction proceeds efficiently in 1,2-dichloroethane at 80–110 °C in the presence of a rhodium catalyst bearing bis(diphenylphosphino)methane (DPPM) as a ligand to afford 1-silacyclopent-2-enes in good to