Recent advances in transition-metal-free carbon–carbon and carbon–heteroatom bond-forming reactions using arynes

Bhunia, Anup; Yetra, Santhivardhana Reddy; Biju, Akkattu T.

doi:10.1039/c2cs15310f

Cited by 602 publications

(154 citation statements)

References 110 publications

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“…Hence, it lies at the heart of the chemical sciences and is regarded as the key transformation in organic synthesis to set up the carbon backbone of organic molecules. [17][18][19][20][21][22][23][24][25][26][27][28] With the advent of the 21st century, the public is equally aware of the hazardous substances used and generated by chemical processes, and eventually the concept of 'green and sustainable chemistry' has evolved. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In the development of organic chemistry, the carbon-carbon bond formation has always been one of the most useful and fundamental reactions, and as a result, there is an ever-growing of methods for carbon-carbon bond formation.…”

Section: ____________________________________________________________mentioning

confidence: 99%

“…117 α-Aminonitriles are the key precursors of diverse α-amino acids for synthesizing proteins, 118 and also as chiral building blocks in pharmaceutical industries. 119 A catalyst-free protocol for the synthesis of racemic αaminonitriles (29) from the reactions of varying carbonyl compounds (26), amines (27), and acetone cyanohydrin (28) via one-pot Strecker reaction in water was reported by Galletti et al (Scheme 10). 120 A good number of entries were found to proceed very efficiently at ambient conditions with high selectivity.…”

Section: C-c Coupling Via Nucleophilic Substitution Reactionmentioning

confidence: 99%

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Design for carbon–carbon bond forming reactions under ambient conditions

Brahmachari

2016

RSC Adv.

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Carbon-carbon (C-C) bond forms the 'backbone' of nearly every organic molecule, and lies at the heart of the chemical sciences! This transformation has always been one of the most useful and fundamental reactions in the development of organic chemistry. Currently, the concept of 'green chemistry' is globally acclaimed and has already advanced quite significantly to come out as a distinct branch of chemical sciences. Among the principles of 'green chemistry', one principle is dedicated to "design of energy efficiency" -that is to develop synthetic strategies that require less/minimum amount of energy to carry out a specific reaction with optimum productivity. And the most effective way-out to save energy is to develop strategies/protocols that are capable enough to carry out the transformations at ambient temperature and pressure! As part of on-going developments on green synthetic strategies, designing for reactions under ambient conditions coupled with other green aspects is, thus, an area of current choice. This review is aimed to offer an up-to-date development on the design of carbon-carbon bond forming protocols to access a wide variety of organic molecules of topical significance under ambient conditions. The account highlights on the brilliant applications of reaction conditions such as the use of solvents or no solvent, catalysts or no catalyst, and the use of green tools like ball-milling, ultrasonication and visible light in achieving the goal! Design for Carbon Carbon Frameworks at Ambient ConditionsN Me Me Me O O COOH Br Br (Graphic for TOC)

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Section: ____________________________________________________________mentioning

confidence: 99%

Section: C-c Coupling Via Nucleophilic Substitution Reactionmentioning

confidence: 99%

Design for carbon–carbon bond forming reactions under ambient conditions

Brahmachari

2016

RSC Adv.

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“…The reaction is assumed to proceed through the 2,3-didehydrobenzofuran intermediate. This ring strain makes them highly reactive, and arynes are widely utilized for the construction of various 1,2-disubstituted benzene derivatives as well as several benzo-fused carbocycles and heterocycles of structural complexity [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Because of the presence of the C-C triple bond installed in a six-membered ring, the unhybridized p-orbitals in arynes are no longer parallel to each other compared with normal alkynes.…”

Section: Introductionmentioning

confidence: 99%

Transition-Metal-Free Synthesis of Benzo-Fused Five- and Six-Membered Heterocycles Employing Arynes

Kaicharla

Biju

2015

Green Synthetic Approaches for Biologically Relevant Heterocycles

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“…The method, operating under very simple and mild conditions, is highly selective and very efficient in producing single regioisomer of the arylated product even on a multigram scale. [12] In an another approach, preoxidizied starting materials were used for the arylation with or without metal-based reagents (Scheme 1, Eq. Moreover, a new approach for C À H arylation based on a novel reactivity that differs from the reactivity in Mannich or Betti reactions of iminium ion is presented.…”

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confidence: 99%

Metal‐ and Oxidant‐Free Direct sp³ CH Arylation of Pyrrolidine

2013

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Arylated aliphatic N-heterocycles, and particularly arylated pyrrolidines, have a wide range of applications in medicine as well as in chemistry. Arylation of pyrrolidines mainly relies on metal-mediated couplings, which produce unwanted toxic metal waste. In this Communication, we report an oxidant-and metal-free method for direct sp 3 C À H arylation of pyrrolidine employing a highly atom economic three-component reaction. The method, operating under very simple and mild conditions, is highly selective and very efficient in producing single regioisomer of the arylated product even on a multigram scale. As an alternative to the metal-mediated reaction, this method has the potential to be used in production at an industrial scale. Moreover, a new approach for C À H arylation based on a novel reactivity that differs from the reactivity in Mannich or Betti reactions of iminium ion is presented.The dependence of human society on functional molecules that serve as advanced materials and medicine is increasing tremendously with time. Accordingly, huge progress has been made for the development of novel methods and strategies to synthesize those functional molecules. During synthesis, excess atomic units in the form of reactants, reagents, solvents or catalysts required to achieve chemical selectivity and molecular complexity are eliminated as chemical waste, which becomes a major problem for the environment. Enormous effort is ongoing to modify known methods and/or to develop new methods for minimizing the production of the chemical waste. Various concepts such as atom economy, [1] redox economy, [2] and step economy [3] were introduced and accepted by the synthetic chemistry community as some of the important parameters for evaluating the practicability of synthetic methods. [4] In this respect, the reaction that involves simple addition of reactants without any other aid from metal-based catalysts, oxidants, and so on, and provides the desired product would be better suited. A very few reactions of this kind (e.g. Diels-Alder, [5] Mannich, [6] Betti reactions, [7] and so on), in comparison with the pool of known chemical processes, are precedented in literature. Therefore, innovative design for the development of new reactions or reformatting the known ones to minimize the waste, keeping the essential features intact (selectivity, yields etc.), is intensely needed.In view of such development, evolutionary efforts are continuing in the context of direct C À H-arylation of saturated N-heterocycles, as a-arylated heterocycles such as arylated pyrrolidines have a wide range of applications in chemistry as well as in medicine. [8, 9] All of the known protocols for efficient direct arylation of saturated N-heterocycles generally involve the use of organometallic reactants either in stoichiometric and/or catalytic amount (Scheme 1, Eq. (1)). [10,11] The metal-mediated reactions are highly efficient in terms of selectivity and reactivity in producing wide variety of valuable C À H arylated heterocyclic compounds. Howev...

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Recent advances in transition-metal-free carbon–carbon and carbon–heteroatom bond-forming reactions using arynes

Cited by 602 publications

References 110 publications

Design for carbon–carbon bond forming reactions under ambient conditions

Design for carbon–carbon bond forming reactions under ambient conditions

Transition-Metal-Free Synthesis of Benzo-Fused Five- and Six-Membered Heterocycles Employing Arynes

Metal‐ and Oxidant‐Free Direct sp³ CH Arylation of Pyrrolidine

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Recent advances in transition-metal-free carbon–carbon and carbon–heteroatom bond-forming reactions using arynes

Cited by 602 publications

References 110 publications

Design for carbon–carbon bond forming reactions under ambient conditions

Design for carbon–carbon bond forming reactions under ambient conditions

Transition-Metal-Free Synthesis of Benzo-Fused Five- and Six-Membered Heterocycles Employing Arynes

Metal‐ and Oxidant‐Free Direct sp3 CH Arylation of Pyrrolidine

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Metal‐ and Oxidant‐Free Direct sp³ CH Arylation of Pyrrolidine