Strain-release C-C bond cleavage enables the [2,3]-sigmatropic rearrangement of tertiary allylamines

2021 ◽  
Author(s):  
Rui-Han Dai ◽  
Lu Han ◽  
Qi Wang ◽  
Shi-Kai Tian
Keyword(s):  
Bond Cleavage ◽  
Sigmatropic Rearrangement ◽  
New Strategy ◽  
Strain Release

A new strategy has been established for the [2,3]-sigmatropic rearrangement of quaternary allylammonium ylides, generated in situ from tertiary allylamines and a bicyclo[1.1.0]butane via strain-release C-C bond cleavage. A range...

Recent Developments in the Asymmetric Detrifluoroacetylative Reactions of in situ Generated Mono-Fluorinated Enolates

2020 ◽  
Vol 24 (18) ◽  
pp. 2181-2191
Author(s):  
Li Wang ◽  
Ziyi Li ◽  
Jiang Liu ◽  
Jianlin Han ◽  
Hiroki Moriwaki ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Bond Cleavage ◽  
Synthetic Methodology ◽  
Research Topics ◽  
Synthetic Organic Chemistry ◽  
Nucleophilic Reactions ◽  
F Center ◽  
Recent Developments

The development of an efficient and mild synthetic methodology for the construction of bioactive fluorine-containing molecules represents one of the hot research topics in general synthetic organic chemistry. In this review, some recent progresses achieved in the development of detrifluoroacetylatively generated mono-fluorinated enolates via CC bond cleavage and their asymmetric nucleophilic reactions for assembly of chiral quaternary C-F center containing compounds.

Molybdenum-Mediated One-Pot Synthesis of Pyrazoles from Isoxazoles

Synthesis ◽  
2019 ◽  
Vol 51 (20) ◽  
pp. 3796-3804 ◽  
Author(s):  
Marine Rey ◽  
Stéphane Beaumont
Keyword(s):  
Bond Cleavage ◽  
Direct Synthesis ◽  
Molybdenum Complex ◽  
One Pot ◽  
One Pot Synthesis ◽  
Wide Range ◽  
Hydrolysis Of ◽  
Substituted Pyrazoles

A one-pot approach for the direct synthesis of substituted pyrazoles from isoxazoles is reported. The process involves isoxazole N–O bond cleavage mediated by a molybdenum complex, in situ hydrolysis of the resulting β-amino enone to the corresponding 1,3-diketone, followed by pyrazole formation in the presence of hydrazine or substituted hydrazine. Good to excellent yields and regioselectivities are obtained with nonsymmetric isoxazoles. By using readily available starting materials, a wide range of substituted pyrazoles may be synthesized by this method.

In Situ Synthesis of Manganese Oxide as an Oxygen‐Evolving Catalyst: A New Strategy

2020 ◽  
Author(s):  
Zahra Abdi ◽  
Robabeh Bagheri ◽  
Mohammad Reza Mohammadi ◽  
Zhenlun Song ◽  
Mikaela Görlin ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
In Situ Synthesis ◽  
New Strategy ◽  
Oxygen Evolving

scholarly journals Vanadium-catalyzed selenide oxidation with in situ [2,3] sigmatropic rearrangement (SOS reaction): scope and asymmetric applications

2004 ◽  
Vol 2 (9) ◽  
pp. 1315-1329 ◽  
Author(s):  
T. Campbell Bourland ◽  
Rich G. Carter ◽  
Alexandre F. T. Yokochi
Keyword(s):  
Sigmatropic Rearrangement

scholarly journals Osteodifferentiation of Human Preadipocytes Induced by Strontium Released from Hydrogels

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Valeria Nardone ◽  
Sergio Fabbri ◽  
Francesca Marini ◽  
Roberto Zonefrati ◽  
Gianna Galli ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Tissue ◽  
Bone Fractures ◽  
Human Adipose Tissue ◽  
Alp Activity ◽  
Skeletal Defects ◽  
New Strategy ◽  
Human Preadipocytes ◽  
Interactive Application

In recent years, there has been an increasing interest in interactive application principles of biology and engineering for the development of valid biological systems for tissue regeneration, such as for the treatment of bone fractures or skeletal defects. The application of stem cells together with biomaterials releasing bioactive factors promotes the formation of bone tissue by inducing proliferation and/or cell differentiation. In this study, we used a clonal cell line from human adipose tissue-derived mesenchymal stem cells (hADSCs or preadipocytes), named PA2-E12, to evaluate the effects of strontium (Sr2+) released in the culture medium from an amidated carboxymethylcellulose (CMCA) hydrogel enriched with different Sr2+concentrations on osteodifferentiation. The osteoinductive effect was evaluated through both the expression of alkaline phophatase (ALP) activity and the hydroxyapatite (HA) production during 42 days of induction. Present data have shown that Sr2+released from CMCA promotes the osteodifferentiation induced by an osteogenic medium as shown by the increase of ALP activity at 7 and 14 days and of HA production at 14 days. In conclusion, the use of biomaterials able to releasein situosteoinductive agents, like Sr2+, could represent a new strategy for future applications in bone tissue engineering.

scholarly journals A Strategy of In Situ Catalysis and Nucleation of Biocompatible Zinc Salts of Amino Acids towards Poly(l-lactide) with Enhanced Crystallization Rate

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 790 ◽  
Author(s):  
Yuan Liang ◽  
Meili Sui ◽  
Maomao He ◽  
Zhiyong Wei ◽  
Wanxi Zhang
Keyword(s):  
Amino Acids ◽  
Crystallization Rate ◽  
Mechanism Study ◽  
Dual Roles ◽  
One Pot ◽  
Amino Acid Ligand ◽  
Nucleation Effect ◽  
New Strategy ◽  
Zinc Salts

The intrinsic drawback of slow crystallization rate of poly(l-lactide) (PLLA) inevitably deteriorates its final properties of the molded articles. In this work, we proposed a new strategy towards poly(l-lactide) with enhanced crystallization rate by ring opening polymerization (ROP) of l-lactide (l-LA) catalyzed by biocompatible zinc salts of amino acids. For the first time we developed a one-pot facile method of zinc salts of amino acids acting dual roles of catalysis of l-LA polymerization and in situ nucleation of the as-prepared PLLA. Nine zinc salts of different amino acids, including three kinds of amino acids ligands (alanine, phenylalanine, and proline) with l/d-enantiomers and their equimolar racemic mixtures, were first prepared and tested as catalysts of l-LA polymerization. A partial racemization was observed for zinc salts of amino acids whereas no racemization was detected for the reference stannous octoate. The polymerization mechanism study showed that the interaction of zinc salts of amino acids and benzyl alcohol forms the actual initiator for l-LA polymerization. Isothermal crystallization kinetics analysis showed that the residual zinc salts of amino acids exhibited a significant nucleation effect on PLLA, evidenced by the promotion of the crystallization rate, depending on the amino acid ligand and its configuration. Meanwhile, the residual zinc salts of amino acids did not compromise the thermal stability of the pristine PLLA.

Cleavage of carbon–carbon bonds by radical reactions

2019 ◽  
Vol 48 (9) ◽  
pp. 2615-2656 ◽  
Author(s):  
Paramasivam Sivaguru ◽  
Zikun Wang ◽  
Giuseppe Zanoni ◽  
Xihe Bi
Keyword(s):  
Bond Cleavage ◽  
Radical Reactions ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Cleavage Reactions

This review provides insights into the in situ generated radicals triggered carbon–carbon bond cleavage reactions.

ChemInform Abstract: Copper-Catalyzed Aerobic Oxidative Inert C-C and C-N Bond Cleavage: A New Strategy for the Synthesis of Tertiary Amides.

ChemInform ◽  
2015 ◽  
Vol 46 (11) ◽  
pp. no-no
Author(s):  
Xiuling Chen ◽  
Tieqiao Chen ◽  
Qiang Li ◽  
Yongbo Zhou ◽  
Li-Biao Han ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
New Strategy ◽  
Tertiary Amides
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