scholarly journals Selective preparation of tetrasubstituted fluoroalkenes by fluorine-directed oxetane ring-opening reactions

2020 ◽  
Vol 16 ◽  
pp. 1936-1946
Author(s):  
Clément Q Fontenelle ◽  
Thibault Thierry ◽  
Romain Laporte ◽  
Emmanuel Pfund ◽  
Thierry Lequeux
Keyword(s):  
Ring Opening ◽  
Fluorine Atom ◽  
Van Der Waals ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Bromide Ions ◽  
Selective Ring Opening ◽  
Oxetane Ring ◽  
Van Der Waals Radii

The selective ring-opening reaction of fluoroalkylidene-oxetanes was directed by the presence of the fluorine atom, enabling a two-step access to tetrasubstituted fluoroalkenes with excellent geometry control. Despite its small van der Waals radii electronic, rather than steric influences of the fluorine atom governed the ring-opening reaction with bromide ions, even in the presence of bulky substituents.

C3-Allylation of Indoles via an Iridium-Catalyzed Branch-Selective Ring-Opening Reaction of Vinylcyclopropanes

Synthesis ◽  
2018 ◽  
Vol 51 (07) ◽  
pp. 1655-1661 ◽  
Author(s):  
Guang-Jian Mei ◽  
Feng Shi ◽  
Lei Yu ◽  
Zi-Qi Zhu ◽  
Meng Sun
Keyword(s):  
Ring Opening ◽  
Economic Approach ◽  
Whole Process ◽  
Ring Opening Reaction ◽  
Selective Ring Opening

An iridium-catalyzed branch-selective ring-opening reaction of vinylcyclopropanes with indoles has been established, which afforded C3-allylindoles in generally good to excellent yields (up to 95%). Considering that no wastes were generated in the whole process and branch-selective ring-opening reaction of vinylcyclopropanes was rarely reported, this strategy not only can be regarded as a highly atom-economic approach for C3-allylindoles, but also will greatly enrich the chemistry of vinylcyclopropanes.

Asymmetric Syntheses of Pyrrolidine and Piperidine Derivatives via Regio- and Stereo-Selective Ring-Opening Reactions of Chiral Aziridine

Heterocycles ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 371 ◽  
Author(s):  
Kimio Higashiyama ◽  
Masataka Matsumura ◽  
Emiko Kurita ◽  
Takayasu Yamauchi
Keyword(s):  
Ring Opening ◽  
Asymmetric Syntheses ◽  
Ring Opening Reactions ◽  
Selective Ring Opening

scholarly journals Torquoselectivity of the Ring-Opening Reaction of 3,3-Dihalosubstituted Cyclobutenes: Lone Pair Repulsion and Cyclic Orbital Interaction

2019 ◽  
Author(s):  
Yuji Naruse ◽  
Atsushi Takamori
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Lone Pair ◽  
Repulsive Interaction ◽  
Orbital Interaction ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Major Factors ◽  
Vacant Orbital ◽  
Model Reactions

<div><div>Three major factors determine torquoselectivity, which is the diastereoselectivity in electrocyclic ring-opening reactions to produce <i>E</i>/<i>Z</i>-double bond(s). One is the interaction between the decomposing s<sub>CC</sub> bond and low-lying vacant orbital(s), such as a p*- or s*-orbital on the substituent, which promotes the reaction, resulting in inward rotation of the substituent. Second, for a substituent with a lone pair(s), repulsive interaction between the decomposing s-bond and the lone pair(s) hinders inward rotation, so that the products of outward rotation should be preferred. Finally, a more strongly donating s-electron-donating group (sEDG) rotates inwardly due to stabilization by phase-continuous cyclic orbital interaction. We compared the latter two interactions, repulsion between the lone pairs on the substituent and stabilization from phase-continuous cyclic orbital interaction, to determine which has a greater effect on the diastereoselectivity. We considered a series of model reactions with halogen substituents, and concluded that the diastereoselectivity is mainly controlled by cyclic orbital interaction.<br></div></div>

scholarly journals Synthesis of new fluorescent molecules having an aggregation-induced emission property derived from 4-fluoroisoxazoles

2020 ◽  
Author(s):  
Kazuyuki Sato ◽  
Akira Kawasaki ◽  
Yukiko Karuo ◽  
Atsushi Tarui ◽  
Kentaro Kawai ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Ring Opening ◽  
Fluorine Atom ◽  
Emission Property ◽  
Synthetic Methods ◽  
Fluorescent Intensity ◽  
Aggregation Induced Emission ◽  
Ring Opening Reaction ◽  
Photochemical Properties ◽  
Fluorescent Molecules

Fluorescent molecules based on a fluorinated isoxazole scaffold were provided for the synthetic methods and their photochemical properties.  Simple 3,5-diarylisoxazoles led to increasing the fluorescent intensity and exhibited a redshift in the emission intensity by introducing a fluorine atom.  α-Fluorinated boron ketoiminates (F-BKIs) derived from a ring opening reaction of 4-fluoroisoxazoles were also synthesized and exhibited a highly fluorescent luminescence as a new aggregation-induced emission (AIE) fluorophore.

scholarly journals Asymmetric ring-opening reaction of meso-epoxides with aromatic amines using homochiral metal–organic frameworks as recyclable heterogeneous catalysts

RSC Advances ◽  
2018 ◽  
Vol 8 (49) ◽  
pp. 28139-28146 ◽  
Author(s):  
Koichi Tanaka ◽  
Maya Kinoshita ◽  
Jun Kayahara ◽  
Yutaro Uebayashi ◽  
Kazusada Nakaji ◽  
...  
Keyword(s):  
Aromatic Amines ◽  
Ring Opening ◽  
Heterogeneous Catalysts ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Amino Alcohols ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Metal Organic ◽  
Asymmetric Ring Opening

Asymmetric ring-opening reactions of meso-epoxides by aromatic amines were achieved by using some chiral metal–organic frameworks. The corresponding β-amino alcohols were obtained with good yields and enantioselectivities (up to 97% ee).

Ring Opening of 1,1’-sulfonyl bis-aziridines Derived from L-Amino Acids and DFT Study on their Affinity Toward Different Nucleophiles

2021 ◽  
Vol 18 ◽  
Author(s):  
Nawel Khettache ◽  
Mohamed Dehamchia ◽  
Sihem Hessainia ◽  
Tahar Abbaz ◽  
Zine Régaïnia
Keyword(s):  
Ring Opening ◽  
Density Functional ◽  
Theoretical Study ◽  
Sodium Ethoxide ◽  
Aziridine Ring ◽  
Functional Theory ◽  
Cyanide Anion ◽  
Anionic Nucleophiles ◽  
Ring Opening Reaction ◽  
Selective Ring Opening

: We describe herein the ring-opening reaction of chiral 1,1’-sulfonyl bis-aziridines with various neutral and anionic nucleophiles, including benzylamine, piperidine, acetate, allyl thiolate, cyanide anion, and sodium ethoxide. These reactions afforded bis-opened or/and mono-opened compounds via a regioselective attack on the non-substituted methylene of aziridine ring. The structures of the products were confirmed based on spectral analysis (IR, 1H NMR, and 13C NMR). A theoretical study involving density functional theory (DFT) was used to rationalize the region-selective ring-opening of starting bis-aziridines.

Thiophene Ring-Opening Reactions III: One-Pot Synthesis and Antitumor Activity of 1,3,4-Thiadiazoline–Benzothiazolo[3,2-b]pyridazine Hybrids

2021 ◽  
Vol 18 ◽  
Author(s):  
Ahmad Ahmad Abdullah ◽  
Jalal Zahra ◽  
Salim Sabri ◽  
Firas Awwadi ◽  
Mohammed Abadleh ◽  
...  
Keyword(s):  
Ring Opening ◽  
Thiophene Ring ◽  
Direct Interaction ◽  
X Ray Diffraction ◽  
One Pot ◽  
One Pot Synthesis ◽  
Ring Opening Reaction ◽  
Ring Opening Reactions ◽  
Intramolecular Cyclizations ◽  
The One

Introduction: The preparation of model 6-chloro-5-nitrothieno[2,3-c]pyridazines incorporating (2'-halo-5'-nitrophenyl) entity is described. Interaction of these substrates with N'-(aryl)benzothiohydrazides, in the presence of triethylamine, followed a formal [4+1] annulation, furnishing the respective 1,3,4-thiadiazoline–benzothiazolo [3,2-b]pyridazine hybrids directly. This one-pot synthesis implies thiophene ring-opening and two consecutive intramolecular cyclizations. The structures of the synthesized new hybrids are supported by MS, NMR, and IR spectral data and further confirmed by single-crystal X-ray diffraction. These hybrids exhibit antiproliferative activity with notable selectivity against solid tumor cell lines (IC50: 4-18 μM). Aims: This study aimed at exploring the scope and applicability of thiophene ring-opening reaction towards the synthesis of new thiadiazoline–[fused]tricyclic conjugates. Background: α-Chloro-β-nitrothienopyridazine underwent ring-opening upon reacting with N'-(aryl)benzothiohydrazides generating 1,3,4-thiadiazoline–benzothiazolo[3,2-b]pyridazines. Objective: This new thiophene ring-opening reaction is applied to the one-pot synthesis of thiadiazoline–benzothiazolo[3,2-b]pyridazine couples. Method: A direct interaction of α-chloro-β-nitrothienopyridazine with N'-(aryl)benzothiohydrazide at room temperature for 1-2 h occurred. Result: α-Chloro-β-nitrothieno[2,3-c]pyridazines are suitable substrates for the facile synthesis of thiadiazoline–benzothiazolo[3,2-b]pyridazine hybrids. Conclusion: This novel ring-opening reaction proceeds via formal [4+1] annulation and provides a versatile approach to various conjugated and/or fused five-membered heterocycles.

Sign in / Sign up

Export Citation Format

Share Document