scholarly journals Oxidative coupling between C(sp2)–H and C(sp3)–H bonds of indoles and cyclic ethers/cycloalkanes

2016 ◽  
Vol 14 (9) ◽  
pp. 2608-2612 ◽  
Author(s):  
Qingjing Yang ◽  
Pui Ying Choy ◽  
Yinuo Wu ◽  
Baomin Fan ◽  
Fuk Yee Kwong
Keyword(s):  
Transition Metal ◽  
Oxidative Coupling ◽  
Cyclic Ethers ◽  
Metal Free ◽  
Dehydrogenative Coupling

Cross-dehydrogenative-coupling (CDC) between C–H/C–H bonds of indoles and cyclic ethers/cycloalkanes is made viable through a simple transition-metal-free pathway.

Metal-Free Regioselective Cross Dehydrogenative Coupling of Cyclic Ethers and Aryl Carbonyls

2019 ◽  
Vol 84 (4) ◽  
pp. 2039-2047 ◽  
Author(s):  
Kishor D. Mane ◽  
Anagh Mukherjee ◽  
Kumar Vanka ◽  
Gurunath Suryavanshi
Keyword(s):  
Cyclic Ethers ◽  
Metal Free ◽  
Dehydrogenative Coupling

Iodine mediated oxidative cross coupling of 2-aminopyridine and aromatic terminal alkyne: a practical route to imidazo[1,2-a]pyridine derivatives

2019 ◽  
Vol 17 (26) ◽  
pp. 6441-6449 ◽  
Author(s):  
Surya Kanta Samanta ◽  
Mrinal K. Bera
Keyword(s):  
Transition Metal ◽  
Oxidative Coupling ◽  
Cross Coupling ◽  
Terminal Alkyne ◽  
Pyridine Derivatives ◽  
Metal Free

A novel, transition-metal free route leading to imidazo[1,2-a]pyridine derivatives via iodine mediated oxidative coupling between 2-aminopyridine and aromatic terminal alkyne has been demonstrated.

scholarly journals Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C–H and sp3 C–H bonds

2016 ◽  
Vol 12 ◽  
pp. 1153-1169 ◽  
Author(s):  
Nivesh Kumar ◽  
Santanu Ghosh ◽  
Subhajit Bhunia ◽  
Alakesh Bisai
Keyword(s):  
Transition Metal ◽  
Alkyl Halides ◽  
One Pot ◽  
Metal Free ◽  
Quaternary Center ◽  
Dehydrogenative Coupling ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds

The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a ‘transition-metal-free’ intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon–carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N-arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction.

scholarly journals Transition-metal-free C(sp3)–H/C(sp3)–H dehydrogenative coupling of saturated heterocycles with N-benzyl imines

2020 ◽  
Vol 11 (29) ◽  
pp. 7619-7625 ◽  
Author(s):  
Zhengfen Liu ◽  
Minyan Li ◽  
Guogang Deng ◽  
Wanshi Wei ◽  
Ping Feng ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Electron Donors ◽  
Metal Free ◽  
Aryl Radicals ◽  
Dehydrogenative Coupling ◽  
Saturated Heterocycles

A unique transition-metal-free C(sp3)–H/C(sp3)–H dehydrocoupling of N-benzylimines with saturated heterocycles is presented using 2-azaallyl anions as super electron donors to initiate the generation of hydrogen atom abstracting aryl radicals.

(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.

KI-mediated radical multi-functionalization of vinyl azides: a one-pot and efficient approach to β-keto sulfones and α-halo-β-keto sulfones

2017 ◽  
Vol 4 (6) ◽  
pp. 1162-1166 ◽  
Author(s):  
Wenteng Chen ◽  
Xingyu Liu ◽  
En Chen ◽  
Binhui Chen ◽  
Jiaan Shao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Oxidative Coupling ◽  
One Pot ◽  
Metal Free ◽  
Efficient Approach ◽  
Vinyl Azides

Transition metal-free oxidative coupling of vinyl azides with sulfonyl hydrazines is described.

Transition Metal-Free Strategies for the Synthesis of C-1 Aryl Substituted Tetrahydroisoquinolines

Synthesis ◽  
2021 ◽  
Author(s):  
Pushpinder Singh ◽  
Aanchal Batra ◽  
Kamal Nain Singh ◽  
Mritunjay Mritunjay
Keyword(s):  
Transition Metal ◽  
Oxidative Coupling ◽  
Metal Salt ◽  
Toxic Metal ◽  
Transition Metal Catalysts ◽  
Bioactive Molecules ◽  
Chemical Waste ◽  
Organometallic Reagents ◽  
Metal Free ◽  
Synthetic Drugs

1-Aryl-1,2,3,4-tetrahydroisoquinolines are important structural motifs and are widely found in bioactive molecules, pharmaceutical and synthetic drugs. In view of increasing environmental awareness, the development of transition metal-free strategies for the synthesis of these compounds is highly desirable. Metal-free oxidative coupling and lithiation methodologies have emerged as effective tools in this area as they exclude the use of transition metal catalysts and help in reducing unwanted and toxic metal based chemical waste in the environment. This review highlights the recent advances in direct arylation of tetrahydroisoquinolines for the synthesis of title compounds in the absence of metal salt. Also, the emphasis has been put on the mechanistic considerations of these reactions. 1 Introduction 2 Arylation of tetrahydroisoquinolines via oxidative coupling 2.1 Arylation using Grignard reagents 2.2 Arylation using other organometallic reagents 2.3 Arylation using aryl organoboranes or arenes 3 Arylation of tetrahydroisoquinolines via lithiation 3.1 Intermolecular arylation 3.2 Intramolecular arylation 4 Conclusions and Outlook

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