Metal-Mediated Controllable Creation of Secondary, Tertiary, and Quaternary Carbon Centers: A Powerful Strategy for the Synthesis of Iron, Cobalt, and Copper Complexes with in Situ Generated Substituted 1-Pyridineimidazo[1,5-a]pyridine Ligands

2012 ◽  
Vol 51 (18) ◽  
pp. 9705-9713 ◽  
Author(s):  
Yanmei Chen ◽  
Lei Li ◽  
Zhou Chen ◽  
Yonglu Liu ◽  
Hailiang Hu ◽  
...  
Keyword(s):  
Copper Complexes ◽  
Quaternary Carbon ◽  
Iron Cobalt ◽  
Carbon Centers ◽  
Pyridine Ligands ◽  
Substituted 1 ◽  
Powerful Strategy

The Catalytic Asymmetric Dearomatization of Tryptamine for Accessing meso-Contiguous Quaternary Carbon Centers of Oligomeric Cyclotryptamine Alkaloids: a Formal Synthesis of Hodgkinsine B

2021 ◽  
Author(s):  
Hongbo Wei ◽  
Guzhou Chen ◽  
Huanhuan Zou ◽  
Zhiqiang Zhou ◽  
Pan Lei ◽  
...  
Keyword(s):  
Quaternary Carbon ◽  
Formal Synthesis ◽  
Carbon Centers ◽  
Catalytic Asymmetric

Herein, we disclosed a catalytic asymmetric dearomatization (CADA) of tryptamine via tandem [4+2] cycloaddition/cyclization with o-azaxylylene in situ generated from functionalized 3-bromooxinidole promoted by chiral N,N’-dioxide/Ni(BF4)2. A variety of dimeric...

scholarly journals Catalyst-free carbosilylation of alkenes using silyl boronates and organic fluorides via selective C-F bond activation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Zhou ◽  
Bingyao Jiang ◽  
Yamato Fujihira ◽  
Zhengyu Zhao ◽  
Takanori Imai ◽  
...  
Keyword(s):  
Double Bond ◽  
Bond Activation ◽  
Single Step ◽  
Side Chain ◽  
Side Reactions ◽  
Quaternary Carbon ◽  
Selective Activation ◽  
Carbon Centers ◽  
Catalyst Free ◽  
Powerful Strategy

AbstractA regioselective carbosilylation of alkenes has emerged as a powerful strategy to access molecules with functionalized silylated alkanes, by incorporating silyl and carbon groups across an alkene double bond. However, to the best of our knowledge, organic fluorides have never been used in this protocol. Here we disclose the catalyst-free carbosilylation of alkenes using silyl boronates and organic fluorides mediated by tBuOK. The main feature of this transformation is the selective activation of the C-F bond of an organic fluoride by the silyl boronate without undergoing potential side-reactions involving C-O, C-Cl, heteroaryl-CH, and even CF3 groups. Various silylated alkanes with tertiary or quaternary carbon centers that have aromatic, hetero-aromatic, and/or aliphatic groups at the β-position are synthesized in a single step from substituted or non-substituted aryl alkenes. An intramolecular variant of this carbosilylation is also achieved via the reaction of a fluoroarene with a ω-alkenyl side chain and a silyl boronate.

Asymmetric Construction of Quaternary Carbon Centers by Sequential Conjugate Addition of Lithium Amide and in Situ Alkylation: Utility in the Synthesis of (−)-Aspidospermidine

2009 ◽  
Vol 11 (3) ◽  
pp. 653-655 ◽  
Author(s):  
Mayuko Suzuki ◽  
Yoshito Kawamoto ◽  
Takeo Sakai ◽  
Yasutomo Yamamoto ◽  
Kiyoshi Tomioka
Keyword(s):  
Conjugate Addition ◽  
Quaternary Carbon ◽  
Lithium Amide ◽  
Carbon Centers

Synthesis, characterization and biological activities of 1,3,4-oxadiazole derivatives of nalidixic acid and their copper complexes

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Nalidixic Acid ◽  
Copper Complexes ◽  
Biological Activities ◽  
Bidentate Coordination ◽  
Antibacterial And Antifungal Activities ◽  
Elemental Analyses ◽  
Oxadiazole Derivatives ◽  
Antibacterial And Antifungal ◽  
Derivatives Of ◽  
Substituted 1

A series of novel 1, 3, 4-oxadiazole analogues was synthesized from cyclization of hydrazones of substituted 1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-naphthyridine-3-carbohydrazides were prepared from nalidixic acid. The structures of synthesized oxadiazole derivatives and their copper complexes were elucidated on the basis of FTIR, elemental analyses, 1H-NMR and atomic absorption spectral analysis. It was observed from spectral data that metal ligand ratio was 1:1 in all copper complexes and they were bidentate, coordination was found to be done through oxygen of 4-oxo group and nitrogen of oxadiazole ring. The synthesized compounds were further evaluated with biological activities and compared with parent hydrazones. Copper complexes possess antibacterial and antifungal activities better than the oxadiazoles while they have better antioxidant activity then copper complexes. Parent hydrazones were better in all biological activities than synthesized oxadiazoles.

Stereocontrolled Synthesis of Highly Functionalized Quaternary Carbon Centers: A Route to α-Substituted Serines

2009 ◽  
Vol 121 (23) ◽  
pp. 4266-4269 ◽  
Author(s):  
Xavier Ariza ◽  
Josep Cornellà ◽  
Mercè Font-Bardia ◽  
Jordi Garcia ◽  
Jordi Ortiz ◽  
...  
Keyword(s):  
Quaternary Carbon ◽  
Carbon Centers ◽  
Stereocontrolled Synthesis
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