Ring-Opening Fluorination of Bicyclic Azaarenes

10.33774/chemrxiv-2021-gh325-v2 ◽

2021 ◽

Author(s):

Masayuki Komatsuda ◽

Ayane Suto ◽

Hiroki Kondo Jr. ◽

Hiroyuki Takada ◽

Kenta Kato ◽

...

Keyword(s):

Functional Groups ◽

Aromatic Ring ◽

Ring Opening ◽

Mechanistic Studies ◽

Electrophilic Fluorination ◽

Ring Opening Reaction ◽

Tertiary Carbon

We have discovered a ring-opening fluorination of bicyclic azaarenes. Upon treatment of bicyclic azaarenes such as pyrazolopyridines with electrophilic fluorinating agents, fluorination of the aromatic ring is followed by a ring-opening reaction. Although this overall trans-formation can be classified as an electrophilic fluorination of an aromatic ring, it is a novel type of fluorination that results in construction of tertiary carbon–fluorine bonds. The present protocol can be applied to a range of bicyclic azaarenes, tolerating azines and a variety of functional groups. Additionally, mechanistic studies and enantioselective fluorination have been examined.

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Visible-light Mediated Ring Opening Reaction of Alkylidenecyclopropanes for the Generation of Homopropargyl Radical

Chemical Science ◽

10.1039/d1sc01889b ◽

2021 ◽

Author(s):

Xiao-Yu Zhang ◽

Chao Ning ◽

Ben Mao ◽

Yin Wei ◽

Min Shi

Keyword(s):

Molecular Structure ◽

Visible Light ◽

Ring Opening ◽

Mechanistic Studies ◽

Radical Process ◽

Ring Opening Reaction ◽

Long Time ◽

Radical Clock

Classical cyclopropylcarbinyl radical clock reactions have been widely applied to conduct the mechanistic studies on probing radical process for a long time; however, alkylidenecyclopropanes, which have a similar molecular structure...

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Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

10.26434/chemrxiv.11467845.v1 ◽

2019 ◽

Author(s):

Marharyta V. Laktsevich-Iskryk ◽

Nastassia A. Varabyeva ◽

Volha V. Kazlova ◽

Vladimir N. Zhabinskii ◽

Vladimir A. Khripach ◽

...

Keyword(s):

Visible Light ◽

Functional Groups ◽

Ring Opening ◽

Radical Intermediates ◽

Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds via radical intermediates and tolerates various functional groups.

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Visible Light-Promoted Catalytic Ring-Opening Isomerization of 1,2-Disubstituted Cyclopropanols to Linear Ketones

10.26434/chemrxiv.11467845 ◽

2019 ◽

Author(s):

Marharyta V. Laktsevich-Iskryk ◽

Nastassia A. Varabyeva ◽

Volha V. Kazlova ◽

Vladimir N. Zhabinskii ◽

Vladimir A. Khripach ◽

...

Keyword(s):

Visible Light ◽

Functional Groups ◽

Ring Opening ◽

Radical Intermediates ◽

Reaction Proceeds

In this article, we report a photocatalytic protocol for the isomerization of 1,2-disubstituted cyclopropanols to linear ketones. The reaction proceeds via radical intermediates and tolerates various functional groups.

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On the Conrotatory Ring Opening of 3-Carbomethoxycyclobutene Vis-À-Vis 3-Carbomethoxy-1,2-Benzocyclobutene and the Predominant Inward Opening of 3-Dimethylaminocarbonyl-1,2-Benzocyclobutene

10.26434/chemrxiv.7094003.v1 ◽

2018 ◽

Author(s):

Veejendra Yadav ◽

Dasari L V K Prasad ◽

Arpita Yadav ◽

Maddali L N Rao

Keyword(s):

Transition State ◽

Ring Opening ◽

Electron Process ◽

Ring Opening Reaction ◽

Stable Species ◽

Electron Event

The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by pC1C2→s*C3C4 and sC3C4→p*CO interactions in the transition state in a 4-electron process as opposed to only sC3C4→p*CO interaction in an apparently 8-electron event in 3-carbomethoxy-1,2-benzocyclobutene. The ring opening of 3-carbomethoxy-1,2-benzocyclobutene is sufficiently endothermic. We therefore argue that the reverse ring closing reaction is faster than the forward ring opening reaction and, thus, it establishes an equilibrium between the two and subsequently allows formation of the more stable species via outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.

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One-step preparation of cyclen-containing hydrophilic polymeric monolithic materials via epoxy-amine ring-opening reaction and their application in enrichment of N-glycopeptides

Talanta ◽

10.1016/j.talanta.2020.122049 ◽

2021 ◽

Vol 225 ◽

pp. 122049

Author(s):

Chen Ma ◽

Ruizhi Tang ◽

Yan Wang ◽

Shujuan Ma ◽

Shouwan Tang ◽

...

Keyword(s):

Ring Opening ◽

Epoxy Amine ◽

Ring Opening Reaction ◽

One Step

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Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽

10.3390/polym13050806 ◽

2021 ◽

Vol 13 (5) ◽

pp. 806

Author(s):

Philipp Marx ◽

Frank Wiesbrock

Keyword(s):

Ring Opening ◽

Covalent Bond ◽

Volumetric Shrinkage ◽

Structure Property ◽

Atomic Packing ◽

Materials Properties ◽

Volumetric Expansion ◽

Structure Property Relationships ◽

Ring Opening Reaction ◽

Measuring Techniques

Commonly, volumetric shrinkage occurs during polymerizations due to the shortening of the equilibrium Van der Waals distance of two molecules to the length of a (significantly shorter) covalent bond. This volumetric shrinkage can have severe influence on the materials’ properties. One strategy to overcome this volumetric shrinkage is the use of expanding monomers that show volumetric expansion during polymerization reactions. Such monomers exhibit cyclic or even oligocyclic structural motifs with a correspondingly dense atomic packing. During the ring-opening reaction of such monomers, linear structures with atomic packing of lower density are formed, which results in volumetric expansion or at least reduced volumetric shrinkage. This review provides a concise overview of expanding monomers with a focus on the elucidation of structure-property relationships. Preceded by a brief introduction of measuring techniques for the quantification of volumetric changes, the most prominent classes of expanding monomers will be presented and discussed, namely cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds. Spiroorthoesters, spiroorthocarbonates, cyclic carbonates, and benzoxazines are particularly highlighted.

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Design and synthesis of 1,8-Naphthalimide Functionalized Benzothiadiazoles

New Journal of Chemistry ◽

10.1039/d1nj00919b ◽

2021 ◽

Author(s):

Rajneesh Misra ◽

Yogjivan Rout

Keyword(s):

Ring Opening ◽

Coupling Reaction ◽

Cross Coupling ◽

Design And Synthesis ◽

Cross Coupling Reaction ◽

Ring Opening Reaction

A series of multi acceptor based push-pull derivatives BTD2–BTD5 were designed and synthesized via Pd-catalyzed Sonogashira cross-coupling reaction followed by [2+2] cycloaddition–electrocyclic ring-opening reaction in which benzothiadiazole (BTD, A1), naphthalimide...

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(1R,4S,5S)-5-((3-Hydroxypropyl)amino)-4-((1-Methyl-1H-tetrazol-5-yl)thio)Cyclopent-2-en-1-ol

Molbank ◽

10.3390/m1199 ◽

2021 ◽

Vol 2021 (2) ◽

pp. M1199

Author(s):

Milene A. G. Fortunato ◽

Filipa Siopa ◽

Carlos A. M. Afonso

Keyword(s):

Spectral Data ◽

13C Nmr ◽

Ring Opening ◽

Environmentally Friendly ◽

Mass Spectral Data ◽

Mass Spectral ◽

Excellent Yield ◽

Ring Opening Reaction ◽

Nucleophilic Ring Opening

Using environmentally friendly conditions, the nucleophilic ring-opening reaction of 6-azabicyclo[3.1.0]hex-3-en-2-ol with 1-methyl-1H-tetrazole-5-thiol provided a novel thiol-incorporated aminocyclopentitol, (1R,4S,5S)-5-((3-hydroxypropyl)amino)-4-((1-methyl-1H-tetrazol-5-yl)thio)cyclopent-2-en-1-ol, in excellent yield (95%). The newly synthesized compound was analyzed and characterized via 1H, 13C-NMR, HSQC, and mass spectral data.

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