A Facile Synthesis of 2-Aminobenzoxazines Based on Iodine­Catalyzed Desulfurative Cyclization

Synthesis ◽  
2021 ◽  
Author(s):  
Shinji Tanimori ◽  
Asuka Fuchiya ◽  
Takuya Miyamura ◽  
Haruna Nariki ◽  
Shizuki Noda ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Transition Metal ◽  
Room Temperature ◽  
Catalytic Amount ◽  
Molecular Iodine ◽  
Environmentally Benign ◽  
Facile Synthesis ◽  
Metal Free ◽  
Catalytic Transformations

AbstractA facile and environmentally benign access to N-aryl/alkyl-4H-benzoxazin-2-amines is achieved from 1-[2-(hydroxymethyl)phenyl/alkyl]-3-phenylthioureas under transition-metal-free conditions. The conversions occur smoothly in the presence of a catalytic amount of molecular iodine and hydrogen peroxide as the oxidant in tetrahydrofuran at room temperature to afford moderate to good yields (28–90%) of the desired products within 2 hours. This method reports the first examples of the catalytic transformations of 1-[2-(hydroxymethyl)phenyl/alkyl]-3-phenylthioureas into N-aryl/alkyl-4H-benzoxazin-2-amines based on desulfurative cyclization.

A metal-free method for facile synthesis of indanones via intramolecular hydroacylation of 2-vinylbenzaldehydes

2021 ◽  
Author(s):  
Guoxue He ◽  
Jinyu Ma ◽  
Jianhui Zhou ◽  
Chunpu Li ◽  
Hong Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Environmentally Benign ◽  
Facile Synthesis ◽  
Metal Free ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

A facile method access to indanones was developed under metal- and additive-free conditions in which L-proline served as efficient and environmentally benign catalysts. Compared with previous indanones synthesis by transition-metal-catalyzed...

TBHP/n-Bu4PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 136-140
Author(s):  
Mehdi Adib ◽  
Rahim Pashazadeh
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Catalytic Amount ◽  
Facile Synthesis ◽  
Butyl Hydroperoxide ◽  
Metal Free ◽  
Tert Butyl ◽  
Dehydrogenative Coupling ◽  
Tert Butyl Hydroperoxide ◽  
Methylene Groups

A transition-metal-free oxidative cross-dehydrogenative coupling reaction has been developed for the preparation of symmetrical carboxylic anhydrides through self-coupling dual C–O bond formations of aryl methanols. In the presence of a catalytic amount of tetrabutylphosphonium bromide (TBPB) as transfer agent and aqueous tert-butyl hydroperoxide (TBHP) as oxidant and reactant, methylene groups of aryl methanols were efficiently oxidized to C=O and coupled with the peroxide oxygen from TBHP to form a diverse array of symmetrical carboxylic anhydride derivatives.

Facile Synthesis of π-Conjugated Heteroaromatic Compounds via Weak-Base-Promoted Transition-Metal-Free C–N Coupling

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1096-1102
Author(s):  
Takahiro Senoo ◽  
Aiko Inoue ◽  
Keiji Mori
Keyword(s):  
Low Temperature ◽  
Transition Metal ◽  
Tertiary Amine ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Weak Base ◽  
Facile Synthesis ◽  
Heteroaromatic Compounds ◽  
Metal Free ◽  
Snar Reaction

A K2CO3-promoted transition-metal-free C–N coupling reaction was developed. When a solution of 1-(2-aminophenyl)-8-iodo­naphthalenes in DMSO was treated with 2.5 equivalents of K2CO3 and 5.0 equivalents of MeI, intramolecular C–N coupling reaction proceeded smoothly even at low temperature (room temperature) to afford various heteroaromatic compounds in good chemical yields. Additional experiments suggested that this reaction might have proceeded through an unusual SNAr reaction between haloarenes and a bulky tertiary amine moiety.

Transition-metal-free and facile synthesis of 3-alkynylpyrrole-2, 4-dicarboxylates from methylene isocyanides and propiolaldehyde

2021 ◽  
Author(s):  
Xiaoli Huo ◽  
Xiaojuan Chen ◽  
Liya Yu ◽  
Chong Zhang ◽  
Linghui Zeng ◽  
...  
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Transformation Process ◽  
Facile Synthesis ◽  
Direct Transformation ◽  
Metal Free

A transition-metal-free, facile and efficient method for the synthesis of 3-alkynylpyrrole-2, 4-dicarboxylates from methylene isocyanides and propiolaldehyde with moderate to good yields has been developed. The direct transformation process and...

Diiiodine/Potassium Persulfate Mediated Synthesis of 1,2,3-Thiadiazoles from N-Tosylhydrazones and a Thiocyanate Salt as a Sulfur Source under Transition-Metal-Free Conditions

Synlett ◽  
2021 ◽  
Author(s):  
Yadong Sun ◽  
Ablimit Abdukader ◽  
Yuhan Lu ◽  
Chenjiang Liu
Keyword(s):  
Transition Metal ◽  
Efficient Method ◽  
Room Temperature ◽  
Functional Group ◽  
Ammonium Thiocyanate ◽  
Potassium Persulfate ◽  
Sulfur Source ◽  
Coupling Reactions ◽  
Wide Scope ◽  
Metal Free

AbstractA highly efficient method for the synthesis of 1,2,3-thiadiazoles has been developed by utilizing readily available tosylhydrazones and ammonium thiocyanate with ecofriendly EtOH as the solvent at room temperature. The reaction shows a wide scope of substrates and good functional-group tolerance. This protocol can be scaled up to a gram level and can be applied to coupling reactions with 4-(4-bromophenyl)-1,2,3-thiadiazole as the substrate.

New Avenues in Radical Trifluoromethylselenylation with ­Trifluoromethyl Tolueneselenosulfonate

Synlett ◽  
2018 ◽  
Vol 30 (07) ◽  
pp. 777-782 ◽  
Author(s):  
Clément Ghiazza ◽  
Cyrille Monnereau ◽  
Lhoussain Khrouz ◽  
Maurice Médebielle ◽  
Thierry Billard ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Transition Metal ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Diazonium Salts ◽  
Metal Free ◽  
Luminescence Measurement ◽  
Stable Reagent ◽  
Shelf Stable

We demonstrated that the shelf-stable reagent trifluoromethyl tolueneselenosulfonate can be involved in radical trifluoromethylselenylation. Upon visible-light irradiation, the homolysis of the reagent could take place at room temperature. This finding is explored for unprecedented C(sp2)–SeCF3 and C(sp3)–SeCF3 processes under transition-metal-free conditions. Mechanistic investigations, including cyclic voltammetry, luminescence measurement, and EPR studies, allowed the proposal of plausible mechanisms.1 Introduction.2 Reactivity of Reagent I with Diazonium Salts3 Reactivity of Reagent I with Alkenes and Alkynes4 Conclusion

Transition metal-free, visible-light-mediated construction of α,β-diamino esters via decarboxylative radical addition at room temperature

2019 ◽  
Vol 6 (13) ◽  
pp. 2245-2249 ◽  
Author(s):  
Guibing Wu ◽  
Jingwen Wang ◽  
Chengyu Liu ◽  
Maolin Sun ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Radical Addition ◽  
Metal Free ◽  
Radical Coupling

A metal-free photoredox catalyzed decarboxylative radical coupling of free-carboxylic acids and glyoxylic oximes was developed to synthesize α,β-diamino acids.

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