Synthesis of 2,2-difluoro-homoallylic alcohols via ring-opening of gem-difluorocyclopropane and aerobic oxidation by photo-irradiation in the presence of an organic pigment

2018 ◽  
Vol 16 (33) ◽  
pp. 6106-6114 ◽  
Author(s):  
Hiroaki Takenaka ◽  
Yoshihiro Masuhara ◽  
Kent Narita ◽  
Toshiki Nokami ◽  
Toshiyuki Itoh
Keyword(s):  
Visible Light ◽  
Ring Opening ◽  
Aerobic Oxidation ◽  
Organic Dye ◽  
Organic Pigment ◽  
Homoallylic Alcohols ◽  
Ring Opening Reaction

The aerobic oxidation took place after the visible light-mediated ring-opening reaction of gem-difluorocyclopropane in the presence of an organic dye and amine to furnish 2,2-difluoro-homoallylic alcohols in good yields.

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

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...

Photocatalytic Degradation of Carbaryl over Novel MWNT-TiO2 Nanocomposite under Visible Light Irradiation

2011 ◽  
Vol 233-235 ◽  
pp. 476-480
Author(s):  
Ke Dai ◽  
Hai Bo Chen ◽  
Xu Li ◽  
Hao Chen ◽  
Qiao Yun Huang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Ring Opening ◽  
Uv Light ◽  
Light Irradiation ◽  
Photodegradation Efficiency ◽  
Uv Light Irradiation ◽  
Ring Opening Reaction ◽  
Visible Light Driven ◽  
Direct Growth

The MWNT-TiO2nanocomposite was synthesized via direct growth of TiO2nanoparticles on the surface of the functionalized MWNTs by the hydrothermal treatment and utilized as the photocatalyst in the carbaryl degradation under both visible light and UV light irradiation. Visible-light-driven activity and enhanced UV-light-driven activity are both achieved as the composite MWNTs with TiO2can efficiently enhance the light absorption and charge separation and then photocatalytic activity. The photodegradation efficiency of carbaryl was examined by HPLC and IC techniques, which demonstrates that carbaryl can be readily degraded under visible light irradiation. Based on the obtained experimental results, assisted with the computer simulation of carbaryl molecule on PM3 level, it is presumed that the degradation of carbaryl starts with the break of N21-C23 and C19-N21 bonds and ends in the generation of naphthalen-1-ol before the ring-opening reaction.

scholarly journals Ring-Opening of Epoxides by Pendant Silanols

2021 ◽  
Author(s):  
SHYAM SATHYAMOORTHI ◽  
Someshwar Nagamalla ◽  
Joel Mague
Keyword(s):  
Phosphoric Acid ◽  
Ring Opening ◽  
Allylic Alcohols ◽  
Homoallylic Alcohols ◽  
Unusual Rearrangement ◽  
Ring Opening Reaction ◽  
Ring Opening Of Epoxides

We present a new ring-opening reaction of epoxides by pendant silanols, catalyzed by either Ph3C+BF4– or BINOL-phosphoric acid. In all cases examined, the reaction is perfectly regioselective and diastereoselective. Silanol epoxides derived from trans-allylic alcohols, cis-allylic alcohols, trans-homoallylic alcohols, and cis-homoallylic alcohols were all compatible and gave products from either endo- or exo-ring opening. With silanol epoxides derived from 4-alkenyl silanols, an unusual rearrangement to tetrahydrofuran products was observed, which is likely the result of tandem nucleophilic attacks. The utility of this methodology was demonstrated in a short preparation of protected D-arabitol.

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

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 <i>via</i> radical intermediates and tolerates various functional groups.

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

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 <i>via</i> radical intermediates and tolerates various functional groups.

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

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

<p>The torquoselectivity of conrotatory ring opening of 3-carbomethoxycyclobutene is controlled by p<sub>C1C2</sub>→s*<sub>C3C4</sub> and s<sub>C3C4</sub>→p*<sub>CO</sub> interactions in the transition state in a 4-electron process as opposed to only s<sub>C3C4</sub>→p*<sub>CO</sub> 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 <i>via</i> outward ring opening reaction. Application of this argument to 3-dimethylaminocarbonyl-1,2-benzocyclobutene explains the predominantly observed inward opening.</p>

Spatial separation of dual-cocatalysts on bismuth vanadate for selective aerobic oxidation of benzylalcohols to benzaldehydes under visible light irradiation

2018 ◽  
Vol 8 (23) ◽  
pp. 6173-6179 ◽  
Author(s):  
Xu Jin ◽  
Rengui Li ◽  
Yue Zhao ◽  
Xiaodan Liu ◽  
Xiaoqi Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Aerobic Oxidation ◽  
Spatial Separation ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Selective Aerobic Oxidation

Efficient converting of alcohols to aldehydes under visible light can be achieved on BiVO4 crystals with spatial separation of dual-cocatalysts.

Metal-free visible-light-induced aerobic oxidation of α-diazoesters leading to α-ketoesters in air

2021 ◽  
Author(s):  
Ruisheng Liu ◽  
Qishun Liu ◽  
Haoran Meng ◽  
Hongyu Ding ◽  
Jindong Hao ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Aerobic Oxidation ◽  
Metal Free

A metal-free and visible-light-induced strategy has been established for the construction of α-ketoesters via aerobic oxidation of α-diazoesters with dioxygen in air at room temperature.

scholarly journals Expanding Monomers as Anti-Shrinkage Additives

Polymers ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document