Tandem Diels–Alder/oxidation–aromatization reactions involving 2-styrylchromones and arynes

2018 ◽  
Vol 16 (33) ◽  
pp. 6077-6085 ◽  
Author(s):  
Yesu Addepalli ◽  
Zhimei Yu ◽  
Jie Ji ◽  
Cheng Zou ◽  
Zhen Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Diels Alder ◽  
Metal Free ◽  
Xanthone Derivatives ◽  
Wide Range

Transition-metal-free tandem Diels–Alder/oxidation–aromatization reactions between 2-styrylchromones and arynes have been demonstrated, providing a wide range of benzo[c]xanthone derivatives with good yields.

Deuterated Aryl Alkyl Ethers Synthesis via Nucleophilic Etherification of Aryl Alkyl Ethers and Thioethers with Deuterated Alcohols

Synlett ◽  
2019 ◽  
Vol 30 (15) ◽  
pp. 1805-1809
Author(s):  
Shuai Li ◽  
Xia Wang ◽  
Xin-Ge Yang ◽  
Gui-Quan Yu ◽  
Xue-Qiang Wang
Keyword(s):  
Transition Metal ◽  
Nucleophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
Metal Free ◽  
Wide Range ◽  
Alkyl Ethers

A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.

scholarly journals Recent Developments in the Synthesis of Pyrido[1,2-a]benzimidazoles

Synthesis ◽  
2018 ◽  
Vol 50 (11) ◽  
pp. 2131-2149 ◽  
Author(s):  
Kamal Kapoor ◽  
Parthasarathi Das ◽  
Rajni Khajuria ◽  
Sk. Rasheed ◽  
Chhavi Khajuria
Keyword(s):  
Transition Metal ◽  
Medicinal Chemistry ◽  
Type I ◽  
Type Ii ◽  
Aromatic Rings ◽  
Metal Free ◽  
Wide Range ◽  
Recent Developments ◽  
Metal Catalyzed ◽  
Synthetic Approaches

Pyrido[1,2-a]benzimidazole is one of the most important azaheterocyclic compounds consisting of three fused aromatic rings. Molecules containing this core have displayed a wide range of applications in the field of medicinal chemistry. The synthesis of pyrido[1,2-a]benzimidazole and its derivatives has attracted organic chemists because of its tremendous utility in interdisciplinary branches of chemistry. In this context, this review discusses the main advances in the synthesis of pyrido[1,2-a]benzimidazoles via metal-mediated and metal-free reactions from 2000 to 2016.1 Introduction2 Synthetic Approaches to Pyrido[1,2-a]benzimidazoles2.1 Type I: Transition-Metal-Catalyzed Methods2.2 Type II: Metal-Free Approaches3 Conclusion

(Diacetoxyiodo)benzene-Mediated Transition-Metal-Free Amination of C(sp3)–H Bonds Adjacent to Heteroatoms with Azoles: Synthesis of N-Alkylated Azoles

Synlett ◽  
2018 ◽  
Vol 29 (18) ◽  
pp. 2432-2436 ◽  
Author(s):  
Can Jin ◽  
Weike Su ◽  
Bin Sun ◽  
Zhiyang Yan
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Coupling Reaction ◽  
Metal Catalyst ◽  
Metal Free ◽  
Alternative Method ◽  
Dehydrogenative Coupling ◽  
Wide Range ◽  
Ready Access

A novel PhI(OAc)2-mediated cross-dehydrogenative coupling reaction of α-C(sp3)–H bonds adjacent to a hetero atom with various azoles has been developed, which provides an alternative method for constructing C–N bonds with high atom efficiency. This new protocol requires no metal catalyst and it provides ready access to a wide range of N-alkylated azole derivatives in moderate to excellent yields by using commercially available PhI(OAc)2 as the sole oxidant. Furthermore, the method is effective on a gram scale, which highlights the practicality of this transformation. The result of radical-captured experiments indicated that the transformation might involve a free-radical pathway.

Transition Metal-Free Synthesis of Pinacol Arylboronate: Regioselective Boronation of 1,3-Disubstituted Benzenes

2014 ◽  
Vol 67 (4) ◽  
pp. 675 ◽  
Author(s):  
Yan Wang ◽  
Le Wang ◽  
Ling-Yan Chen ◽  
Pinaki S. Bhadury ◽  
Zhihua Sun
Keyword(s):  
Transition Metal ◽  
Regioselective Synthesis ◽  
Ortho Position ◽  
Metal Free ◽  
Disubstituted Benzene ◽  
Wide Range

The regioselective synthesis of pinacol arylboronate has been achieved from 1,3-disubstituted benzene through directed ortho-metallation (DoM)–borylation sequence. A wide range of substituents and borylating reagents were investigated. In situ lithiation and subsequent boronation predominantly occurred at the ortho-position to afford the desired products in moderate yields.

Stitching Triazoles to Arenes via a Transition Metal-Free Aryne Diels–Alder/1,3-Prototropic Shift/Dehydrobromination Cascade

2021 ◽  
Author(s):  
Ranadeep Talukdar ◽  
Vikram Singh ◽  
Hemlata Mourya ◽  
Malik Nasibullah ◽  
Bhoopendra Tiwari
Keyword(s):  
Transition Metal ◽  
Diels Alder ◽  
Metal Free

Coupling of N-Nosylhydrazones with Nitrosoarenes: Transition-Metal-Free Approach to (Z)-N-Arylnitrones

Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1728-1736 ◽  
Author(s):  
Tingting Liu ◽  
Zhaohong Liu ◽  
Zhenhua Liu ◽  
Donghua Hu ◽  
Yeming Wang
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Direct Coupling ◽  
Recrystallization Process ◽  
Metal Free ◽  
Mild Conditions ◽  
Wide Range

An efficient and transition-metal-free protocol for the synthesis of (Z)-N-arylnitrones from the direct coupling of N-nosylhydrazones with nitrosoarenes under mild conditions is described. The protocol is compatible with a wide range of functional groups placed on both the reagents and provided the corresponding nitrones in good to excellent yields by simple recrystallization process. The use of these 1,3-dipoles for the synthesis of substituted indoles is elaborated for 2,3-diphenyl-1H-indole.

Transition-metal free decarboxylative ipso amination of aryl carboxylic acids

2021 ◽  
Author(s):  
Jing Zhang ◽  
Ye-Xing Hou ◽  
Yan-Liu Tang ◽  
Ji-Hang Xu ◽  
Zi-Kui Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Carboxylic Acids ◽  
Metal Free ◽  
Wide Range

A convenient DMAP-catalysed decarboxylative amination of aryl and alkyl carboxylic acids is developed under transition-metal-free conditions. This reaction allows the sustainable synthesis of a wide range of aryl and alkyl...

Chemoselective and Metal-Free Synthesis of Aryl Esters from the Corresponding Benzylic Alcohols in Aqueous Medium Using TBHP/TBAI as an Efficient Catalytic System

Synlett ◽  
2018 ◽  
Vol 29 (16) ◽  
pp. 2208-2212
Author(s):  
Sanjay Bhar ◽  
Sneha Nandy ◽  
Avishek Ghatak ◽  
Asit Das
Keyword(s):  
Transition Metal ◽  
Catalytic Amount ◽  
High Yield ◽  
Primary Alcohols ◽  
Benzylic Alcohols ◽  
Metal Free ◽  
Tishchenko Reaction ◽  
Tert Butyl Hydroperoxide ◽  
Wide Range ◽  
Tetrabutylammonium Iodide

A novel and transition-metal-free strategy has been developed for the synthesis of aryl esters starting from corresponding benzylic primary alcohols as the exclusive substrates using tert-butyl hydroperoxide (TBHP) as a terminal oxidant in the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and imidazole, where the aliphatic alcohols remained unaffected. These reactions are highly chemoselective and associated with high yield and wide applicability accommodating a wide range of substituents. Excellent chemoselectivity has also been demonstrated through intramolecular competition experiments. This protocol can be considered as an important analogue of Tishchenko reaction using benzylic alcohols as the substrates instead of benzaldehydes.

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