Recyclable organotungsten Lewis acid and microwave assisted Diels–Alder reactions in water and in ionic liquids
作者:I-Hon Chen、Jun-Nan Young、Shuchun Joyce Yu
DOI:10.1016/j.tet.2004.09.078
日期:2004.12
water-soluble, organotungsten Lewisacid, [OP(2-py)3W(CO)(NO)2](BF4)2 (1), was synthesized and characterized. A series of 1-catalyzed Diels–Alderreactions were investigated under conventional heating or microwave heating conditions. The cycloaddition reactions were efficiently conducted in either water or in an ionicliquid, 1-butyl-3-methylimidazolium hexafluorophosphate. The ionicliquid acts as a powerful
Ruthenium-catalyzed C–H oxygenation of quinones by weak O-coordination for potent trypanocidal agents
作者:Gleiston G. Dias、Torben Rogge、Rositha Kuniyil、Claus Jacob、Rubem F. S. Menna-Barreto、Eufrânio N. da Silva Júnior、Lutz Ackermann
DOI:10.1039/c8cc07572g
日期:——
C–H oxygenation of quinones by weak O-coordination was achieved by versatile ruthenium(ii) catalysis with ample substrate scope and trypanocidal compounds were also identified.
对醌的C-H氧化通过多功能钌(II)催化实现,具有广泛的底物范围,并且还发现了抗锥虫化合物。
Organocatalytic double arylation of 3-isothiocyanato oxindoles: Stereocontrolled synthesis of complex spirooxindoles
作者:Lin-Lin Zhang、Bing-Chao Da、Shao-Hua Xiang、Shuai Zhu、Zi-Yun Yuan、Zhen Guo、Bin Tan
DOI:10.1016/j.tet.2018.11.016
日期:2019.3
employed as the electrophiles for the organocatalyticMichael addition/cyclization cascade reaction with versatile 3-isothiocyanato oxindoles. Chiral bifunctional organocatalyst was appropriate for this enantioselective transformation to afford a variety of novel spirooxindoles, possessing a spirocyclic stereocenter adjacent to the aromatic ring, via asymmetricdouble arylation. These synthesized spirooxindoles
calcination of the Sn–W hydroxide at 800 °C acts as an effective and reusable solid catalyst for CCbond‐formingreactions, such as the cyclization of citronellal, the Diels–Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (see scheme). The observed catalysis was truly heterogeneous, and the recovered catalyst could be reused without loss of its high catalytic performance
Ruthenium(II)‐Catalyzed Double Annulation of Quinones: Step‐Economical Access to Valuable Bioactive Compounds
作者:Eufrânio N. Silva Júnior、Renato L. Carvalho、Renata G. Almeida、Luisa G. Rosa、Felipe Fantuzzi、Torben Rogge、Pedro M. S. Costa、Claudia Pessoa、Claus Jacob、Lutz Ackermann
DOI:10.1002/chem.202001434
日期:2020.8.26
Double ruthenium(II)‐catalyzed alkyne annulations of quinones were accomplished. Thus, a strategy is reported that provides step‐economical access to valuable quinones with a wide range of applications. C−H/N−H activations for alkyne annulations of naphthoquinones provided challenging polycyclic quinoidal compounds by forming four new bonds in one step. The singular power of the thus‐obtained compounds