Mild and Efficient Reductive Deoxygenation of Epoxides to Olefins with Tin(II) Chloride/Sodium Iodide as a Novel Reagent
作者:Naseem Ahmed、Gulab Pathe
DOI:10.1055/s-0034-1378821
日期:——
times and high yields. A highly efficient and green protocol is reported for the reductive deoxygenation of organic epoxides to olefins usingtin(II) chloride/sodium iodide as a novel reagent. The reaction gives an excellent yield (85–96%) in ethanol under reflux within 2–10 minutes, without affecting other functional groups. The advantages of our method are the use of inexpensive reagents, the eco-friendly
Phosphonylpyrazoles from Bestmann−Ohira Reagent and Nitroalkenes: Synthesis and Dynamic NMR Studies
作者:Rajendran Muruganantham、Irishi Namboothiri
DOI:10.1021/jo902595e
日期:2010.4.2
also included Morita−Baylis−Hillman adducts of conjugated nitroalkenes with various electrophiles. Detailed dynamicNMRstudies were performed on the prototropic tautomerism exhibited by the phosphonylpyrazoles using CDCl3 and DMSO-d6 as solvents and 1H and 31P as the probe nuclei. These studies unraveled the existence of two tautomers in solution with a small energy difference but considerable barrier
1-重氮-2-氧代丙基膦酸二乙酯(Bestmann-Ohira试剂)作为硝基烯与环加成伙伴的应用已得到广泛研究。Bestmann-Ohira试剂与各种硝基烯烃(例如,碳环或杂环的一部分的β-取代的,α,β-二取代的和硝基乙烯)进行的碱介导反应通过室温下的一锅区域选择性反应提供了官能化的磷酸ny唑。高产。这些反应中使用的取代硝基烯烃还包括共轭硝基烯烃与各种亲电试剂的森田-贝利斯-希尔曼加合物。使用CDCl 3和DMSO- d 6作为溶剂,对膦酰基吡唑显示的质子互变异构进行了详细的动态NMR研究。1 H和31 P作为探针核。这些研究揭示了溶液中两种互变异构体的存在,它们的能量差很小,但对互变具有很大的障碍。
Bifunctional acid–base ionic liquid for the one-pot synthesis of fine chemicals: Thioethers, 2H-chromenes and 2H-quinoline derivatives
作者:Maria J. Climent、Sara Iborra、Maria J. Sabater、Juan D. Vidal
DOI:10.1016/j.apcata.2014.05.004
日期:2014.7
A bifunctionalorganocatalyst with ionicliquid properties and with an optimized distancebetween the acid and basic sites efficiently activates electron deficient olefins for 1,4 conjugated addition, which can be incorporated in different one-pot transformations for the preparation of cyclic and acyclic compounds of biological and synthetic interest. More specifically, the catalyst can be successfully
Facile access to 2-aryl-3-nitro-2H-chromenes and 2,3,4-trisubstituted chromanes
作者:Ping-An Wang、Dong-Xu Zhang、Xue-Ying Liu
DOI:10.3998/ark.5550190.p008.801
日期:——
materials, 2-aryl-3-nitro-2H-chromenes were prepared in good yields (up to 83%) through the combination of 30 mol% of pyrrolidine- benzoic acid catalyzed tandem oxa-Michael-Henry reactions in refluxing ethanol. Additionally, the Michael reactions of 2-aryl-3-nitro-2H-chromenes with acetone were also performed by the same catalytic combination in brine to give 2,3,4-trisubstitutedchromanes up to 86%
Molecular diversity of the domino annulation reaction of 2-aryl-3-nitrochromenes with pivaloylacetonitriles
作者:Wang Jiang、Jing Sun、Ru-Zhang Liu、Chao-Guo Yan
DOI:10.1039/c8ob01504j
日期:——
In the presence of triethylamine, the domino annulation reaction of two molecules of pivaloylacetonitrile with one molecule of 2-aryl-3-nitrochromene in tetrahydrofuran resulted in the unprecedented imino-substituted dihydrofuro[2,3-c]chromene derivatives in high yields.