Transition-metal-free C–C bond cleavage and formation: efficient synthesis of 2,3-diarylimidazo[1,2-α]pyridines from 2-aminopyridines and alkynoates

RSC Advances ◽  
2016 ◽  
Vol 6 (89) ◽  
pp. 86464-86467 ◽  
Author(s):  
Zhengwang Chen ◽  
Yuelu Wen ◽  
Guotian Luo ◽  
Min Ye ◽  
Qinghao Wang
Keyword(s):  
Transition Metal ◽  
Bond Cleavage ◽  
Cyclization Reaction ◽  
Efficient Synthesis ◽  
Metal Free ◽  
Highly Efficient

A highly efficient transition-metal-free cyclization reaction for the synthesis of 2,3-diarylimidazo[1,2-α]pyridines is described.

Transition-metal free alkylarylation of acrylamides initiated by radical C–C bond cleavage of the tertiary cycloalkanols

RSC Advances ◽  
2016 ◽  
Vol 6 (32) ◽  
pp. 27000-27003 ◽  
Author(s):  
Li-Na Guo ◽  
Zhi-Qiang Deng ◽  
Yong Wu ◽  
Jie Hu
Keyword(s):  
Transition Metal ◽  
Formation Process ◽  
Bond Cleavage ◽  
Radical Cyclization ◽  
Cyclization Reaction ◽  
One Pot ◽  
Metal Free ◽  
Tertiary Cycloalkanols

An efficient Na2S2O8-promoted radical cyclization reaction of acrylamides with the tertiary cycloalkanols has been developed. This one pot procedure involves a tandem C–C bond cleavage and two C–C bonds formation process.

Transition-Metal-Free Efficient Synthesis of Bisindole Sulfanes Using 2-(Fluorosulfonyl)difluoroacetic Acid

Synlett ◽  
2018 ◽  
Vol 29 (14) ◽  
pp. 1847-1850
Author(s):  
Yang Li ◽  
Lan-Ting Shi ◽  
Wen-Qing Zhu ◽  
Hong Li ◽  
Qiang Zhang
Keyword(s):  
Transition Metal ◽  
Efficient Synthesis ◽  
Metal Free ◽  
Highly Efficient ◽  
Difluoroacetic Acid

By using 2-(fluorosulfonyl)difluoroacetic acid as sulfur ­reagent, bisindole sulfanes were highly efficient synthesized under transition-metal-free conditions. Results indicate that this proceeded not at the relatively acidic C-2 position but rather selectively at the nucleo­philic C-3 position to give the desired compounds with excellent regio­selectivities and good yields.

Transition-metal-free highly efficient synthesis of 2-pyridones from β-keto amides and ynals

2019 ◽  
Vol 60 (18) ◽  
pp. 1265-1267 ◽  
Author(s):  
Zhengwang Chen ◽  
Jiayang Liu ◽  
Caiju Jin ◽  
Qi Tan ◽  
Min Ye
Keyword(s):  
Transition Metal ◽  
Efficient Synthesis ◽  
Metal Free ◽  
Highly Efficient

scholarly journals A gold-catalyzed alkyne-diol cycloisomerization for the synthesis of oxygenated 5,5-spiroketals

2011 ◽  
Vol 7 ◽  
pp. 570-577 ◽  
Author(s):  
Sami F Tlais ◽  
Gregory B Dudley
Keyword(s):  
Transition Metal ◽  
Lewis Acids ◽  
Gold Catalysis ◽  
Late Transition Metal ◽  
Efficient Synthesis ◽  
Highly Efficient ◽  
Late Transition

A highly efficient synthesis of oxygenated 5,5-spiroketals was performed towards the synthesis of the cephalosporolides. Gold(I) chloride in methanol induced the cycloisomerization of a protected alkyne triol with concomitant deprotection to give a strategically hydroxylated 5,5-spiroketal, despite the potential for regiochemical complications and elimination to furan. Other late transition metal Lewis acids were less effective. The use of methanol as solvent helped suppress the formation of the undesired furan by-product. This study provides yet another example of the advantages of gold catalysis in the activation of alkyne π-systems.

One-pot transition-metal free transamidation to sterically hindered amides

2018 ◽  
Vol 5 (20) ◽  
pp. 2950-2954 ◽  
Author(s):  
Weijie Guo ◽  
Jingjun Huang ◽  
Hongxiang Wu ◽  
Tingting Liu ◽  
Zhongfeng Luo ◽  
...  
Keyword(s):  
Transition Metal ◽  
Good Yield ◽  
One Pot ◽  
Metal Free ◽  
Highly Efficient ◽  
Sterically Hindered

A highly efficient one-pot transamidation of primary amides has been developed under transition-metal free conditions, generating a variety of amides including hindered amides in good yield (up to 86%) catalyzed by CsF.

scholarly journals Selective C-N σ Bond Cleavage in Azetidinyl Amides under Transition Metal-Free Conditions

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 459 ◽  
Author(s):  
Hengzhao Li ◽  
Zemin Lai ◽  
Adila Adijiang ◽  
Hongye Zhao ◽  
Jie An
Keyword(s):  
Electron Transfer ◽  
Transition Metal ◽  
Transfer Reaction ◽  
Bond Cleavage ◽  
Electron Transfer Reaction ◽  
Amide Bond ◽  
Single Electron Transfer ◽  
Reaction Conditions ◽  
Metal Free ◽  
Single Electron Transfer Reaction

Functionalization of amide bond via the cleavage of a non-carbonyl, C-N σ bond remains under-investigated. In this work, a transition-metal-free single-electron transfer reaction has been developed for the C-N σ bond cleavage of N-acylazetidines using the electride derived from sodium dispersions and 15-crown-5. Of note, less strained cyclic amides and acyclic amides are stable under the reaction conditions, which features the excellent chemoselectivity of the reaction. This method is amenable to a range of unhindered and sterically encumbered azetidinyl amides.

scholarly journals Na2CO3-promoted thioesterification via N–C bond cleavage of amides to construct thioester derivatives

2019 ◽  
Vol 43 (11-12) ◽  
pp. 486-492
Author(s):  
Jiasi Tao ◽  
Weijie Yu ◽  
Jin Luo ◽  
Tao Wang ◽  
Wanling Ge ◽  
...  
Keyword(s):  
Transition Metal ◽  
Bond Cleavage ◽  
Metal Free

A mild, efficient, and transition-metal-free catalytic strategy is developed to construct thioesters via selective N–C bond cleavage of Boc2-activated primary amides. This strategy is successfully carried out with stoichiometric Na2CO3 as the base and provides the corresponding products in moderate to excellent yields.

Catalytic conversion of ketones to esters via C(O)–C bond cleavage under transition-metal free conditions

2020 ◽  
Vol 56 (58) ◽  
pp. 8143-8146
Author(s):  
Murugan Subaramanian ◽  
Palmurukan M. Ramar ◽  
Jagannath Rana ◽  
Virendra Kumar Gupta ◽  
Ekambaram Balaraman
Keyword(s):  
Transition Metal ◽  
Bond Cleavage ◽  
Catalytic Conversion ◽  
Metal Free

The catalytic conversion of ketones to esters via C(O)–C bond cleavage under transition-metal free conditions is reported.

Transition-Metal-Free, Intermolecular Azidoheteroarylation of Alkenes: Efficient Access to β-Azidoalkylated Quinoxalinones and Preliminary Antifungal Evaluation Against Magnaporthe grisea

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2395-2409
Author(s):  
Weiwei Qin ◽  
Zhaodong Li ◽  
Yiming Du ◽  
Yue Chen ◽  
Yun-Lin Liu
Keyword(s):  
Transition Metal ◽  
Magnaporthe Grisea ◽  
Single Step ◽  
Domino Reaction ◽  
Efficient Synthesis ◽  
Metal Free ◽  
Efficient Access ◽  
First Time ◽  
Antibacterial Evaluation ◽  
Addition Pathway

An efficient, PhI(OAc)2-mediated, radical azidoheteroarylation of alkenes under transition-metal-free conditions is reported by employing TMSN3 and quinoxalin-2(1H)-ones as coupling partners. This domino reaction allows an efficient synthesis of valuable orangoazides containing quinoxalin-2(1H)-one derivatives and could be extended to phosphinyl-alkylated quinoxalin-2(1H)-one in a single step in moderate to excellent yields under mild conditions, as demonstrated by the preliminary antibacterial evaluation against Magnaporthe grisea for the first time. Mechanistic studies revealed that this transformation undergoes a cascade addition pathway controlled by a polar radical.

scholarly journals Highly Efficient Synthesis of Hindered 3-Azoindoles via Metal-Free C–H Functionalization of Indoles

Synthesis ◽  
2020 ◽  
Vol 52 (04) ◽  
pp. 574-580
Author(s):  
Nicolas Jacob ◽  
Lucas Guillemard ◽  
Joanna Wencel-Delord
Keyword(s):  
Steric Hindrance ◽  
Room Temperature ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Photochromic Compounds ◽  
Metal Free ◽  
Highly Efficient ◽  
Simple Protocol ◽  
Potential Applications

Although 3-azoindoles have recently emerged as an appealing family of photoswitch molecules, the synthesis of such compounds has been poorly covered in the literature. Herein a high-yielding and operationally simple protocol is reported allowing the synthesis of 3-azoindoles, featuring important steric hindrance around the azo motif. Remarkably, this C–H coupling is characterized by excellent atom economy and occurs under metal-free conditions, at room temperature, and within few minutes, delivering the expected products in excellent yields (quantitatively in most of the cases). Accordingly, a library of new molecules, with potential applications as photochromic compounds, is prepared.

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