Changing stereoselectivity and regioselectivity in copper(<scp>i</scp>)-catalyzed 5-<i>exo</i> cyclization by chelation and rigidity in aminoalkyl radicals: synthesis towards diverse bioactive N-heterocycles
作者:Sandhya Sadanandan、Dharmendra Kumar Gupta
DOI:10.1039/c9nj05166j
日期:——
Chelation, rigidity and carbon-radical positions in aminoalkyl precursors disturb the usual 2,4-trans diastereoselectivity and 5-exo mode in Cu(i)-catalyzed ATRC.
Synthesis of 1,2,4-Oxadiazoles by Tandem Reaction of Nitroalkenes with Arenes and Nitriles in the Superacid TfOH
作者:Andrei A. Golushko、Olesya V. Khoroshilova、Aleksander V. Vasilyev
DOI:10.1021/acs.joc.9b00812
日期:2019.6.7
The tandem reaction of nitroalkenes with arenes and nitriles in the superacid CF3SO3H (TfOH) results in the formation of 1,2,4-oxadiazole derivatives in yields up to 96%. This reaction proceeds via the consequent interaction of arenes and nitriles, as nucleophiles, with intermediate cationic species derived by the protonation of nitroalkenes in TfOH. This is novel and general synthesis of 1,2,4-oxadiazoles
在超强酸CF 3 SO 3 H(TfOH)中硝基烯烃与芳烃和腈的串联反应导致形成1,2,4-恶二唑衍生物,收率高达96%。该反应通过作为亲核试剂的芳烃和腈与由TfOH中硝基烯烃的质子化衍生的中间阳离子物质的相互作用而进行。这是1,2,4-恶二唑的新颖且通用的合成方法,它们是药物化学中非常重要的化合物。
Uncatalyzed reactions of α-(trihaloethylidene)nitroalkanes with push–pull enamines: a new type of ring–ring tautomerism in cyclobutane derivatives and the dramatic effect of the trihalomethyl group on the reaction pathway
作者:Vladislav Yu. Korotaev、Alexey Yu. Barkov、Pavel A. Slepukhin、Mikhail I. Kodess、Vyacheslav Ya. Sosnovskikh
DOI:10.1016/j.tetlet.2011.08.109
日期:2011.11
A new type of ring–ring isomerism, which consists of the reversible transformation of cyclobutane derivatives into substituted 1,2-oxazine N-oxides was found and studied by NMR spectroscopy and X-ray diffraction analysis. The starting materials were prepared by the stereoselective reaction of α-(trifluoroethylidene)nitroalkanes, which react with ethyl β-morpholino- and β-piperidinocrotonates at the
Copper(I)-Promoted Synthesis of Highly Substituted and Functionalized Tetrahydrothiophenes
作者:Ram N. Ram、Dharmendra Kumar Gupta、Vineet Kumar Soni
DOI:10.1002/ejoc.201600497
日期:2016.7
Copper(I)-promoted 5-exo halogen-atom-transfer radical cyclization of 2,2,2-trihaloethylallyl sulfides gave highly functionalized tetrahydrothiophenes in good to high yields. Stereochemical aspects of the diastereomeric mixtures of products formed under different reaction conditions were evaluated, and single-crystal diffraction analysis and 2D NMR spectroscopic analysis were carried out. The synthetic
Simple synthesis of functionalized 7-aza-2H-chromenes from pyridoxal and nitroalkenes in aqueous medium
作者:V. Yu. Korotaev、A. Yu. Barkov、V. Ya. Sosnovskikh
DOI:10.1007/s11172-012-0101-y
日期:2012.3
A reaction of 1-nitro-3,3,3-trichloro(trifluoro)propenes and β-nitrostyrene with pyridoxal hydrochloride in the presence of sodium hydroxide in aqueous medium gives good yields of new derivatives of 7-aza-2H-chromene system.