scholarly journals A Merged Aldol Condensation, Alkene Isomerization, Cycloaddition/Cycloreversion Sequence Employing Oxazinone Intermediates for the Synthesis of Substituted Pyridines

Synlett ◽  
2017 ◽  
Vol 28 (10) ◽  
pp. 1170-1172 ◽  
Author(s):  
Jonathan Scheerer ◽  
Jill Williamson ◽  
Emily Smith
Keyword(s):  
Aldol Condensation ◽  
Reaction Vessel ◽  
Diels Alder ◽  
Domino Reaction ◽  
Reaction Sequence ◽  
Alkene Isomerization ◽  
Substituted Pyridines

A domino reaction sequence has been evaluated that begins with union of novel dihydrooxazinone precursors with 2-alkynyl-substituted benzaldehyde components through aldol condensation. Ensuing operations, including alkene isomerization, Diels–Alder, and retrograde Diels–Alder with loss of CO2 occurs in the same reaction vessel to provide polysubstituted tricyclic pyridine products.

Transition metal-free approach to azafluoranthene scaffolds by aldol condensation/[1+2+3] annulation tandem reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes

2021 ◽  
Author(s):  
Penghui Dong ◽  
Kashif Majeed ◽  
lingna Wang ◽  
Zijian Guo ◽  
Fengtao Zhou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Aldol Condensation ◽  
Domino Reaction ◽  
Tandem Reaction ◽  
Metal Free ◽  
Successive Formation ◽  
General Synthesis

A transition metal-free aldol condensation/[1+2+3] annulation reaction of isocyanoacetates with 8-(alkynyl)-1-naphthaldehydes has been developed for the general synthesis of azafluoranthenes. This domino reaction enables successive formation of three new bonds...

scholarly journals Metal-Free Four-Step Domino Reaction Enables Fully Controlled Non-Statistical Synthesis of Hexaarylbenzene with Six Different Aryl Groups

2021 ◽  
Author(s):  
Benedikt Grau ◽  
Maximilian Dill ◽  
Frank Hampel ◽  
Axel Kahnt ◽  
Norbert Jux ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Diels Alder ◽  
Domino Reaction ◽  
Aromatic Rings ◽  
Light Emitting ◽  
Crystalline Materials ◽  
Metal Free ◽  
Synthetic Strategy ◽  
Starting Compound ◽  
Liquid Crystalline Materials

Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, redox materials, organic light-emitting diodes and photochemical switches. Statistical synthesis of simple symmetrical HABs is known <i>via</i> low-yielding cyclotrimerization or Diels-Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB <i>via</i> an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and <i>α,α</i>-dicyanoolefins as easily available starting materials. Resulting domino product – functionalized triarylbenzene (TAB) - can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to creating diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core.

scholarly journals 1,1,4,4-Tetracyanobutadiene-Functionalized Anthracenes: Regioselectivity of Cycloadditions in the Synthesis of Small Near-IR Dyes

2020 ◽  
Author(s):  
Clotilde Philippe ◽  
Anh Thy Bui ◽  
Sabrinah Batsongo-Boulingui ◽  
ziemowit Pokladek ◽  
Katarzyna Matczyszyn ◽  
...  
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Reaction Sequence ◽  
Near Ir

<p>Two small 1,1,4,4-tetracyanobutadiene-functionalized chromophores were obtained by careful leverage of the regioselectivity of the cycloaddition reaction of tetracyanoethylene with anthracene-ynamide derivatives, inducing either a [2+2] or a [4+2] Diels–Alder process. DFT calculations unraveled the mechanism of the [2+2] cycloaddition-retroelectrocyclization reaction sequence with ynamides and elucidated the differing mechanisms in the two substrates. The synthesized dyes presented panchromatic absorption extending into the near-IR, and far-red/near-IR photoluminescence in the solid-state up to 1550 nm.</p>

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