Stereospecific cobalt-mediated enediyne cyclization involving a tetrasubstituted double bond: one-step construction of the hydrophenanthrene nucleus incorporating two adjacent quaternary centers

1984 ◽  
Vol 49 (25) ◽  
pp. 5010-5012 ◽  
Author(s):  
Max Malacria ◽  
K. Peter C. Vollhardt
Keyword(s):  
Double Bond ◽  
Quaternary Centers ◽  
One Step

Rapid construction of complex tetracyclic frameworks via a gold(i)-catalyzed tandem 1,2-acyloxy migration/[3 + 2] cycloaddition/Friedel–Crafts type cyclization reaction of linear enynyl esters

2017 ◽  
Vol 4 (11) ◽  
pp. 2109-2113 ◽  
Author(s):  
Haiyu Sun ◽  
Shiyan Xu ◽  
Zhimin Xing ◽  
Lin Liu ◽  
Shangbiao Feng ◽  
...  
Keyword(s):  
Cyclization Reaction ◽  
Quaternary Centers ◽  
Rapid Construction ◽  
One Step

Magic “Au”: 3 rings and 2–3 quaternary centers were constructed in one step!

scholarly journals Synthesis of new A-conjugated Quinolone and Spiroindole Dammaranes by the Ozonolysis of 2,3-Indolodipterocarpol

2018 ◽  
Vol 13 (5) ◽  
pp. 1934578X1801300
Author(s):  
Irina E. Smirnova ◽  
Elmira F. Khusnutdinova ◽  
Alexander N. Lobov ◽  
Oxana B. Kazakova
Keyword(s):  
Double Bond ◽  
13C Nmr ◽  
Dipolar Cycloaddition ◽  
Intramolecular Rearrangements ◽  
Efficient Access ◽  
One Step ◽  
New Compounds

An one-step and efficient access to the new dammarane A-quinolones by ozonolysis of 2,3-indolodipterocarpol at 0°C through the 1,3-dipolar cycloaddition of ozone to the C2-C3 double bond of the triterpenoid core is reported. In the case of oxidation in AcOH, two spiroindoles were identified as a result of 1,2-cycloaddition of ozone to the C2-C3 double bond with following intramolecular rearrangements of 2,3-epoxy-intermediate. The structures of four new compounds were established by 1H, 13C NMR, COSY, NOSY, HMBC and HSQC analyses.

A Direct Synthesis of a Strongly Zwitterionic 6,6'-Diaminofulvalene

2014 ◽  
Vol 69 (5) ◽  
pp. 580-588 ◽  
Author(s):  
Dominic Schmid ◽  
Alexander Seyboldt ◽  
Doris Kunz
Keyword(s):  
Double Bond ◽  
Theoretical Analysis ◽  
Dft Calculations ◽  
Structure Analysis ◽  
Direct Synthesis ◽  
Exocyclic Double Bond ◽  
X Ray ◽  
One Step ◽  
Initial Route ◽  
Guanidinium Salt

Upon reaction of the dipyrido-anellated guanidinium salt 1 with one equivalent of CpNa we were able to synthesize the dipyrido-anellated diaminofulvalene 4 in one step in 33% isolated yield. This shortens the initial route that applies a literature-known fulvalene synthesis via uronium salt 3 by two steps and avoids the need for a sacrificial equivalent of CpNa. Although the X-ray structure analysis reveals a shorter exocyclic double bond than observed in the diaminofulvalene V, a theoretical analysis based upon DFT calculations shows a stronger zwitterionic character for the dipyridofulvalene 4.

scholarly journals Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

2021 ◽  
Vol 17 ◽  
pp. 1565-1590
Author(s):  
Thiago S Silva ◽  
Fernando Coelho
Keyword(s):  
Double Bond ◽  
Hydrogen Atom Transfer ◽  
Transfer Reactions ◽  
Quaternary Carbon ◽  
Bond Functionalization ◽  
Quaternary Centers ◽  
Carbon Centers ◽  
Wide Availability ◽  
Hydride Hydrogen ◽  
Molecular Complexity

Olefin double-bond functionalization has been established as an excellent strategy for the construction of elaborate molecules. In particular, the hydroalkylation of olefins represents a straightforward strategy for the synthesis of new C(sp3)–C(sp3) bonds, with concomitant formation of challenging quaternary carbon centers. In the last 20 years, numerous hydroalkylation methodologies have emerged that have explored the diverse reactivity patterns of the olefin double bond. This review presents examples of olefins acting as electrophilic partners when coordinated with electrophilic transition-metal complexes or, in more recent approaches, when used as precursors of nucleophilic radical species in metal hydride hydrogen atom transfer reactions. This unique reactivity, combined with the wide availability of olefins as starting materials and the success reported in the construction of all-carbon C(sp3) quaternary centers, makes hydroalkylation reactions an ideal platform for the synthesis of molecules with increased molecular complexity.

scholarly journals One-Step Synthesis of Novel Renewable Vegetable Oil-Based Acrylate Prepolymers and Their Application in UV-Curable Coatings

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1165 ◽  
Author(s):  
Yupei Su ◽  
Hai Lin ◽  
Shuting Zhang ◽  
Zhuohong Yang ◽  
Teng Yuan
Keyword(s):  
Double Bond ◽  
Vegetable Oil ◽  
Reaction Rate ◽  
Rapid Development ◽  
Practical Significance ◽  
Organic Polymer ◽  
Cross Linking ◽  
Uv Curable ◽  
One Step ◽  
The Cross

With the rapid development of social economy, problems such as volatile organic compound (VOC) pollution and the excessive consumption of global petroleum resources have become increasingly prominent. People are beginning to realize that these problems not only affect the ecological environment, but also hinder the development of the organic polymer material industry based on raw fossil materials. Therefore, the modification and application of bio-based materials are of theoretical and practical significance. In this study, a series of vegetable oil-based acrylate prepolymers were synthesized by one-step acrylation using palm oil, olive oil, peanut oil, rapeseed oil, corn oil, canola oil, and grapeseed oil as raw materials, and the effect of different double bond contents on the product structure and grafting rate was investigated. Furthermore, the as-prepared vegetable oil-based acrylate prepolymers, polyurethane acrylate (PUA-2665), trimethylolpropane triacrylate (TMPTA), and photoinitiator (PI-1173) were mixed thoroughly to prepare ultraviolet (UV)-curable films. The effect of different grafting numbers on the properties of these films was investigated. The results showed that as the degree of unsaturation increased, the acrylate grafting number and the cross-linking density increased, although the acrylation (grafting reaction) rate decreased. The reason was mainly because increasing the double bond content could accelerate the reaction rate, while the grafted acrylic groups had a steric hindrance effect to prevent the adjacent double bonds from participating in the reaction. Furthermore, the increase in grafting number brought about the increase in the structural functionality of prepolymers and the cross-linking density of cured films, which led to the enhancement in the thermal (glass transition temperature) and mechanical (tensile strength, Young’s modulus) properties of the cured films.

scholarly journals Microwave-assisted reactions: Efficient and versatile one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones under controlled microwave heating

2021 ◽  
Vol 10 (1) ◽  
pp. 201-207
Author(s):  
Ramadan Ahmed Mekheimer ◽  
Alaa M. Hayallah ◽  
Moustafa Sherief Moustafa ◽  
Saleh Mohammed Al-Mousawi ◽  
Mohamed Abd-Elmonem ◽  
...  
Keyword(s):  
Double Bond ◽  
Microwave Irradiation ◽  
Microwave Heating ◽  
Biologically Relevant ◽  
Microwave Assisted ◽  
One Step

Abstract We report herein a simple and efficient one-step synthesis of 8-substituted xanthines and substituted pyrimidopteridine-2,4,6,8-tetraones via reaction of 1,3-dimethyl-5,6-diaminouracil 1 with activated double bond systems 2 assisted by controlled microwave irradiation. The obtained heterocycles are privileged biologically relevant scaffolds.

One-Step Access to Luminescent Pentaaryldiazaboroles via C–C Double Bond Formation from Imidoylstannanes

2012 ◽  
Vol 134 (36) ◽  
pp. 14666-14669 ◽  
Author(s):  
Dawei Tian ◽  
Jiang Jiang ◽  
Hongfan Hu ◽  
Jianying Zhang ◽  
Chunming Cui
Keyword(s):  
Double Bond ◽  
Bond Formation ◽  
One Step
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