scholarly journals Azaindole synthesis through dual activation catalysis with N-heterocyclic carbenes

2016 ◽  
Vol 52 (59) ◽  
pp. 9283-9286 ◽  
Author(s):  
Hayden A. Sharma ◽  
M. Todd Hovey ◽  
Karl A. Scheidt
Keyword(s):  
Transition Metal ◽  
Heterocyclic Carbenes ◽  
Metal Free ◽  
Dual Activation ◽  
High Yields

A convergent, transition-metal-free synthesis of 2-aryl-azaindoles enabled by carbene catalysis is reported with high yields and a wide substrate scope featuring previously inaccessible azaindoles.

scholarly journals Recent Advances in Transition-Metal-Free (4+3)-Annulations

Synthesis ◽  
2021 ◽  
Author(s):  
Heather Lam ◽  
Mark Lautens ◽  
Xavier Abel-Snape ◽  
Martin F. Köllen
Keyword(s):  
Transition Metal ◽  
Boronic Acid ◽  
Lewis Acids ◽  
Acid Catalysis ◽  
Heterocyclic Carbenes ◽  
Bronsted Acids ◽  
Metal Free ◽  
Previous Review ◽  
Dual Activation ◽  
Metal Catalyzed

Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion

An Iodide-Mediated Transition-Metal-Free Strategy towards Unsymmetrical Diaryl Sulfides via Arylhydrazines and Thiols

Synthesis ◽  
2019 ◽  
Vol 52 (05) ◽  
pp. 727-734 ◽  
Author(s):  
Farnaz Jafarpour ◽  
Mohammad Asadpour ◽  
Meysam Azizzade ◽  
Mehran Ghasemi ◽  
Saideh Rajai-Daryasarei
Keyword(s):  
Transition Metal ◽  
Room Temperature ◽  
Bond Formation ◽  
Antidepressant Drug ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Potential Utility ◽  
Metal Free ◽  
Cross Coupling Reaction ◽  
High Yields

A mild, scalable iodine-mediated oxidative cross-coupling reaction of arylhydrazines and thiols for construction of thioethers (sulfides) in the absence of any transition metals or photocatalysts is disclosed. A variety of unsymmetrical diaryl sulfides with broad substrate scope both on thiols and hydrazines were synthesized in high yields in water at room temperature. Furthermore, to demonstrate the utility of the protocol, the above C–S bond formation was applied in the synthesis of the key structure of vortioxetine as an antidepressant drug. The gram-scale outcome also added to the potential utility of this protocol.

Straightforward route to γ-sultams via novel SN/Michael addition tandem

Synthesis ◽  
2020 ◽  
Author(s):  
Anastasiia Klochkova ◽  
Andrey Bubyrev ◽  
Dmitrii Viktorovich Dar'in ◽  
Olga Yu. Bakulina ◽  
Mikhail Krasavin ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Michael Addition ◽  
X Ray ◽  
Metal Free ◽  
X Ray Crystallography ◽  
High Yields

A novel tandem approach to trisubstituted γ-sultams has been developed involving N-alkylation of methanesulfonanilides with EWG-substituted allyl bromides followed by intramolecular Michael addition. A series of various isothiazolidine 1,1-dioxides has been prepared under mild transition metal-free conditions in high yields and trans-diastereoselectivity (confirmed by X-ray crystallography). The dependence of reactivity on electronic properties of substrates has been investigated.

scholarly journals Transition Metal-free Epoxidation of Alkenes Based on the Existence of (2- hydroxypropyl)-β-CD

2015 ◽  
Vol 9 (1) ◽  
pp. 20-24
Author(s):  
Shi Dongpo ◽  
Yin Xianqing ◽  
Zheng Yancheng ◽  
Chen wu ◽  
Fu Jiaxin ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Transition Metal ◽  
Sodium Bicarbonate ◽  
Ambient Temperature ◽  
Metal Free ◽  
High Yields ◽  
Epoxidation Of Alkenes

A green, efficient epoxidation of alkenes with hydrogen peroxide (HO) and sodium bicarbonate (NaHCO3) catalyzed by (2-hydroxypropyl)-β-cyclodextrin (2-hp-β-CD) in aqueous solution has been investigated in detail. A range of alkenes were epoxidized at ambient temperature with high yields.

Transition-Metal-Free Synthesis of Trifluoromethylated Furans via a Bu3P-Mediated Tandem Acylation–Wittig Reaction

Synlett ◽  
2020 ◽  
Vol 31 (20) ◽  
pp. 2035-2038
Author(s):  
Wei Zhou ◽  
Maizhan Li
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Nucleophilic Addition ◽  
Wittig Reaction ◽  
Reaction Conditions ◽  
Metal Free ◽  
Highly Efficient ◽  
Intramolecular Wittig Reaction ◽  
High Yields

AbstractA highly efficient nucleophilic addition–O-acylation–intramolecular Wittig reaction of β-trifluoromethyl α,β-enones is disclosed. This strategy features mild reaction conditions and provides a practical transition-metal-free method to a set of biologically significant trifluoromethylated furans in high yields with diverse functional groups.

Transition-Metal-Free C–H Arylation of Unactivated Arenes with 8-Hydroxyquinoline as a Promoter

Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1721-1727 ◽  
Author(s):  
Deyan Wu ◽  
Yinuo Wu ◽  
Xuehua Zheng ◽  
Xu-Nian Wu ◽  
Jing-Yi Chen ◽  
...  
Keyword(s):  
Transition Metal ◽  
Structural Diversity ◽  
Aromatic Substitution ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Aryl Bromides ◽  
Reaction Proceeds ◽  
High Yields ◽  
Biaryl Compounds

A method for the transition-metal-free direct C–H arylation of unactivated arenes is developed with aryl bromides as substrates and 8-hydroxyquinoline as an efficient promoter. A variety of biaryl compounds with structural diversity are obtained in moderate to high yields. Mechanistic studies reveal that the reaction proceeds via a homolytic­ aromatic substitution pathway.

Visible-Light-Driven Phosphonoalkylation of Alkenes

Synlett ◽  
2021 ◽  
Vol 32 (04) ◽  
pp. 378-382
Author(s):  
Yue-Ming Jiang ◽  
Jie Liu ◽  
Qiang Fu ◽  
Yu-Ming Yu ◽  
Da-Gang Yu
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Functional Group ◽  
Reaction Conditions ◽  
Metal Free ◽  
Alkyl Sulfonates ◽  
Visible Light Driven ◽  
High Yields

AbstractPhosphonylation of alkenes is important for the generation of valuable organophosphines. However, redox-neutral difunctionalization of alkenes with readily available H-P(O) compounds remains underdeveloped. Herein, we report the first visible-light-driven redox-neutral phosphonoalkylation of alkenes. A variety of organophosphorus-containing three-membered carbocyclic scaffolds are synthesized from alkene-bearing alkyl sulfonates with H-P(O) compounds. The transition-metal-free protocol displays good functional group tolerance, broad substrate scope, high yields, and mild reaction conditions.

Transition-Metal-Free Synthesis of Thiosulfonates through Radical Coupling Reaction

Synlett ◽  
2018 ◽  
Vol 29 (15) ◽  
pp. 2076-2080 ◽  
Author(s):  
Wen-Ting Wei ◽  
Zhiyong Guo ◽  
Guodong Zhou ◽  
Xu-Dong Xu ◽  
Gan-Ping Chen
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Coupling Process ◽  
Metal Free ◽  
Radical Coupling ◽  
Radical Coupling Reaction ◽  
High Yields

An efficient and practical transition-metal-free radical ­coupling reaction of sulfonyl hydrazides mediated by NIS/K2S2O8 has been developed to afford a variety of biological activity thiosulfonates in moderate to excellent yields. Compared to a known approach for the synthesis of thiosulfonates from sulfonyl hydrazides, this strategy features high yields, mild reaction conditions, and broad substrate scope. The mechanistic studies revealed that the procedure undergoes via a radical cross-coupling process for the construction of S–S bonds.

Transition Metal-free Trifluoroethoxylation of Diaryliodonium Salts and Fluoro Alcohols

2019 ◽  
Vol 16 (6) ◽  
pp. 485-490
Author(s):  
Jian Li ◽  
Zhengbing Wang ◽  
Xuechen Lu ◽  
Jing Lin ◽  
Li Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Functional Group ◽  
Metal Free ◽  
Diaryliodonium Salts ◽  
High Yields

A method for the synthesis of aryl trifluoroethyl ethers from fluoroalcohols and diaryliodonium salts in the presence of NaH and warm 1,2-dichloroethane has been developed. This transition metal free reaction is mild and facile. Various functional group including electron-withdrawing and electron-donating substrates in the diaryliodonium salts were tolerated in this transformation to afford the products in moderate to high yields.

Sign in / Sign up

Export Citation Format

Share Document