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.

Visible-Light-Promoted C2 Trifluoromethylation of Quinoline N-Oxides

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 219-226 ◽  
Author(s):  
Ce Liang ◽  
Wang-Tao Zhuo ◽  
Yan-Ning Niu ◽  
Guo-Lin Gao
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Room Temperature ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Reaction Proceeds

A photoredox catalytic strategy has been described for the direct C2 trifluoromethylation of quinoline N-oxides. This reaction is compatible with a range of synthetically relevant functional groups for providing efficient synthesis of a variety of C2 trifluoromethyl quinoline N-oxides at room temperature. Mechanistic studies indicated that the reaction proceeds via a radical pathway.

Photocatalytic Stoichiometric Oxidant-Free Synthesis of Linear Unsaturated Ketones from 1,2-Disubstituted Cyclopropanols

Synthesis ◽  
2020 ◽  
Author(s):  
Alaksiej L. Hurski ◽  
Marharyta V. Laktsevich-Iskryk ◽  
Anastasiya V. Krech ◽  
Vladimir N. Zhabinskii ◽  
Vladimir A. Khripach
Keyword(s):  
Visible Light ◽  
Ring Opening ◽  
Unsaturated Ketones ◽  
Air Atmosphere ◽  
Reaction Proceeds ◽  
One Step

AbstractA one-step catalytic oxidant-free synthesis of unsaturated ketones from 1,2-disubstituted cyclopropanols is reported. Previously for this transformation, only two- and three-step protocols have been developed. The reaction proceeds under irradiation with visible light in the presence of catalytic amounts of both an acridinium photocatalyst and a cobaloxime complex. 2-Aryl-substituted cyclopropanols react giving α,β-unsaturated ketones, while dehydrogenative ring opening of 2-alkyl-substituted substrates affords mixtures of α,β- and β,γ-enones. The reaction starts with one-electron oxidation of a cyclopropanol to cyclopropyloxy radical, presumably, by the photoexcited acridinium catalyst. We also found that Co(dmgBF2)2(MeCN)2 complex under an air atmosphere and irradiation with blue LEDs or upon heating can serve as a hydroxycyclopropane oxidant.

Visible-Light-Triggered Decarboxylative Alkylation of 8-Acylaminoquinoline with N-Hydroxyphthalimide Ester

Synlett ◽  
2020 ◽  
Vol 31 (07) ◽  
pp. 677-682 ◽  
Author(s):  
Bin Sun ◽  
Deyu Li ◽  
Xiaohui Zhuang ◽  
Rui Zhu ◽  
Aertuke Aisha ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Efficient Approach ◽  
Radical Coupling ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Operational Simplicity

A facile protocol for visible-light-induced decarboxylative radical coupling of NHP esters with 8-aminoquinoline amides is reported, affording a highly efficient approach to synthesize a variety of 2-alkylated or 2,4-dialkylated 8-aminoquinoline derivatives. The reaction proceeds smoothly without adding any ligand, and provides the corresponding products containing a wide range of functional groups in moderate to excellent yields. This reaction uses readily available starting materials, and proceeds under mild conditions and with operational simplicity.

Visible Light-Mediated Oxidative Debenzylation

2020 ◽  
Author(s):  
Cristian Cavedon ◽  
Eric T. Sletten ◽  
Amiera Madani ◽  
Olaf Niemeyer ◽  
Peter H. Seeberger ◽  
...  
Keyword(s):  
Reaction Time ◽  
Visible Light ◽  
Functional Groups ◽  
Continuous Flow ◽  
Protecting Groups ◽  
Benzyl Ether ◽  
Complex Molecules ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Harsh Conditions

Protecting groups are key in the synthesis of complex molecules such as carbohydrates to distinguish functional groups of similar reactivity. The harsh conditions required to cleave stable benzyl ether protective groups are not compatible with many other protective and functional groups. The mild, visible light-mediated debenzylation disclosed here renders benzyl ethers orthogonal protective groups. Key to success is the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as stoichiometric or catalytic photooxidant such that benzyl ethers can be cleaved in the presence of azides, alkenes, and alkynes. The reaction time for this transformation can be reduced from hours to minutes in continuous flow. <br>

Catalytic Enantioselective Benzylation Directly from Aryl Acetic Acids

2018 ◽  
Author(s):  
Patrick Moon ◽  
Zhongyu Wie ◽  
Rylan Lundgren
Keyword(s):  
Functional Group ◽  
Terminal Event ◽  
Radical Intermediates ◽  
Carbon Carbon Bond ◽  
Or Groups ◽  
Reaction Proceeds ◽  
Wide Availability ◽  
Metal Catalyzed ◽  
The Stability ◽  
Acetic Acids

The stability and wide availability of carboxylic acids make them valuable reagents in chemical synthesis. Most transition metal catalyzed processes using carboxylic acid substrates are initiated by a decarboxylation event that generates reactive carbanion or radical intermediates. Developing enantioselective methodologies relying on these principles can be challenging, as highly reactive species tend to react indiscriminately without selectivity. Furthermore, anionic or radical intermediates generated from decarboxylation can be incompatible with protic and electrophilic functionality, or groups that undergo trapping with radicals. We demonstrate that metal-catalyzed enantioselective benzylation reactions of allylic electrophiles can occur directly from aryl acetic acids. The reaction proceeds via a pathway in which decarboxylation is the terminal event, occurring after stereoselective carbon–carbon bond formation. The mechanistic features of the process enable enantioselective benzylation without the generation of a highly basic nucleophile. Thus, the process has broad functional group compatibility that would not be possible employing established protocols.<br>

Reactions of 4-Pyrones with Azomethine Ylides as a Chemo­selective Method for the Construction of Multisubstituted Pyrano[2,3-c]pyrrolidines

Synthesis ◽  
2021 ◽  
Author(s):  
Dmitrii L. Obydennov ◽  
Vyacheslav D. Steben’kov ◽  
Konstantin L. Obydennov ◽  
Sergey A. Usachev ◽  
Vladimir S. Moshkin ◽  
...  
Keyword(s):  
Double Bond ◽  
Ring Opening ◽  
Azomethine Ylides ◽  
Azomethine Ylide ◽  
Dipolar Cycloaddition ◽  
Computational Studies ◽  
Carbon Double Bond ◽  
Reactivity Indexes ◽  
Reaction Proceeds

Abstract4-Pyrones bearing electron-donating and electron-withdrawing groups react with nonstabilized azomethine ylides to form pyrano[2,3-c]pyrrolidines in moderate to good yields. The reaction proceeds chemoselectively as a 1,3-dipolar cycloaddition of the azomethine ylide at the carbon–carbon double bond of the pyrone activated by the electron-withdrawing substituent. The reactivity of 4-pyrones toward azomethine ylides was rationalized by computational studies with the use of reactivity indexes. The pyrano[2,3-c]pyrrolidine moiety could be modified, for example by a ring-opening transformation under the action of hydrazine to provide pyrazolyl-substituted pyrrolidines.

Studies in polymerization. XIII. The activated initiation of vinyl polymerization by metal carbonyls

1962 ◽  
Vol 268 (1335) ◽  
pp. 553-566 ◽  
Keyword(s):  
Kinetic Mechanism ◽  
Molybdenum Hexacarbonyl ◽  
Metal Carbonyls ◽  
Group Vi ◽  
Radical Intermediates ◽  
Vinyl Polymerization ◽  
Organic Halogen ◽  
Halogen Compounds ◽  
Iodine Compounds ◽  
Reaction Proceeds

It has been found that the hexaearbonyls of group VI metals in the presence of some organic halogen compounds are active initiators of vinyl polymerization. Molybdenum hexacarbonyl is the most active, and halogen compounds containing —CC1 3 , —CBr 3 are generally more effective than those with fewer halogen atoms joined to a single carbon. Fluorine and iodine compounds are inactive. A study has been made of the initiation of the polymerization of methyl methacrylate by the Cr(CO) 6 + CCl 4 system. The polymerization is markedly retarded by carbon monoxide. It is shown that the reaction proceeds through free-radical intermediates, and a kinetic mechanism for initiation is derived (equation (4)) leading to the expression (5) for the rate of chain starting. This quantity may be calculated from (5) with the aid of the numerical values in table 3. Kinetic observations are in satisfactory agreement with this mechanism. The nature of the participating reactions is discussed.

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.

Syntheses of 4-Allyl-/4-allenyl-4-(arylthio)-1,4-dihydroisoquinolin-3-ones via Photochemical Doyle-Kirmse reaction

2021 ◽  
Author(s):  
Jianwei Xie ◽  
Muhammad Suleman ◽  
Zaibin Wang ◽  
Xinfei Mao ◽  
Beibei Mao ◽  
...  
Keyword(s):  
Visible Light ◽  
Diazo Compounds ◽  
Reaction Proceeds

Facile syntheses of 4-allyl-/4-allenyl-4-(arylthio)-1,4-dihydroisoquinolin-3-ones via visible-light-induced Doyle-Kirmse reaction of 4-diazo-1,4-dihydroisoquinolin-3-ones with allyl-/propargyl sulfides is reported. The reaction proceeds via generation of free carbenes from cyclic diazo compounds followed by in...

Sign in / Sign up

Export Citation Format

Share Document