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Trinadh Kaicharla, Birte M. Zimmermann, Martin Oestreich, and Johannes F. Teichert
Chemical Communications, ISSN: 13597345, eISSN: 1364548X, Pages: 13410-13413, Published: 2019 Royal Society of Chemistry (RSC)
Copper(i)/N-heterocyclic carbene complexes enable a catalytic transfer semihydrogenation of alkynes employing simple and readily available alcohols such as isopropanol.
Manas Das, Trinadh Kaicharla, and Johannes F. Teichert
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 4926-4929, Published: 17 August 2018 American Chemical Society (ACS)
A catalytically generated vinylcopper complex, the reactive intermediate of a copper(I)-catalyzed alkyne transfer hydrogenation, can be trapped by commercially available halogen electrophiles. In this manner, internal alkynes can stereoselectively be hydrohalogenated to the corresponding vinyl chlorides, bromides, and iodides.
Anu Jacob, Tony Roy, Trinadh Kaicharla, and Akkattu T. Biju
Journal of Organic Chemistry, ISSN: 00223263, eISSN: 15206904, Pages: 11269-11274, Published: 20 October 2017 American Chemical Society (ACS)
An operationally simple and metal-free cross-coupling of quinone monoacetals (QMAs) with 2-naphthols catalyzed by triflic acid is reported. This formal [3+2] annulation allowed the synthesis of diverse naphtho[2,1-b]benzofuran derivatives in moderate to good yields. Preliminary mechanistic studies reveal the initial nucleophilic substitution of QMAs with 2-naphthols in preference to the mixed acetal formation and subsequent [3,3] sigmatropic rearrangement.
Trinadh Kaicharla, Anu Jacob, Rajesh G. Gonnade, and Akkattu T. Biju
Chemical Communications, ISSN: 13597345, eISSN: 1364548X, Pages: 8219-8222, Published: 2017 Royal Society of Chemistry (RSC)
The reaction of 2-naphthols with aziridines in the presence of AgOTf proceeding in a dehydrative, [3+2] annulation leading to benzoindolines is reported.
Tony Roy, Manikandan Thangaraj, Trinadh Kaicharla, Rupa V. Kamath, Rajesh G. Gonnade, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 5428-5431, Published: 21 October 2016 American Chemical Society (ACS)
Arynes are employed in the transition-metal-free and mild [2,3] Stevens rearrangement of tertiary allylic amines for the synthesis of functionalized homoallylic amines in moderate to good yield with a broad substrate scope. The key nitrogen ylide intermediate was generated by the N-arylation of allyl amines using arynes. Moreover, the reaction of chiral allyl amines with arynes resulted in the enantiospecific synthesis of homoallylic amines. In addition, preliminary studies on the [1,2] Stevens rearrangement is also presented.
Trinadh Kaicharla, Tony Roy, Manikandan Thangaraj, Rajesh G. Gonnade, and Akkattu T. Biju
Angewandte Chemie - International Edition, ISSN: 14337851, eISSN: 15213773, Pages: 10061-10064, Published: 2016 Wiley
Lewis acid-catalyzed reactions of 2-substituted cyclopropane 1,1-dicarboxylates with 2-naphthols is reported. The reaction exhibits tunable selectivity depending on the nature of Lewis acid employed and proceed as a dearomatization/rearomatization sequence. With Bi(OTf)3 as the Lewis acid, a highly selective dehydrative [3+2] cyclopentannulation takes place leading to the formation of naphthalene-fused cyclopentanes. Interestingly, engaging Sc(OTf)3 as the Lewis acid, a Friedel-Crafts-type addition of 2-naphthols to cyclopropanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields.
Tony Roy, Sachin Suresh Bhojgude, Trinadh Kaicharla, Manikandan Thangaraj, Bikash Garai, and Akkattu T. Biju
Organic Chemistry Frontiers, ISSN: 20524110, eISSN: 20524129, Pages: 71-76, Published: January 2016 Royal Society of Chemistry (RSC)
The transition-metal-free aryne multicomponent coupling (MCC) involving carboxylic acids initiated by aziridines/azetidines leading to the synthesis of N-aryl β/γ-amino alcohol derivatives has been developed.
Trinadh Kaicharla and Akkattu T. Biju
Green Synthetic Approaches for Biologically Relevant Heterocycles, Pages: 45-76, Published: 2015 Elsevier
A comprehensive overview of the synthesis of various benzo-fused five- and six-membered heterocyclic compounds utilizing a transition-metal-free approach employing arynes is the focal theme of this chapter. The synthesis of these heterocycles has been achieved under green and operationally simple procedures using a mild method for the generation of arynes by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates developed by Kobayashi and coworkers in 1983. Consequently, arynes have been employed for the construction of multisubstituted arenes of structural diversity and complexity. The versatile transition-metal-free applications of arynes include cycloaddition reactions, insertion reactions, and multicomponent reactions for the construction of various heterocycles.
Anup Bhunia, Trinadh Kaicharla, Digvijay Porwal, Rajesh G. Gonnade, and Akkattu T. Biju
Chemical Communications, ISSN: 13597345, eISSN: 1364548X, Pages: 11389-11392, Published: 28 August 2014 Royal Society of Chemistry (RSC)
Although nucleophilic phosphine-catalysis is a powerful tool for the construction of various carbocycles and heterocycles, the reactions in which phosphines are incorporated into the final product are rare, and the reports on phosphine addition to highly electrophilic arynes are scarce. Herein, we report the phosphine triggered multicomponent reaction of arynes and aldehydes, which takes place via the formal [3+2] cycloaddition of an initially generated 1,3-phosphonium zwitterion from phosphines and arynes with aldehydes. The reaction resulted in the formation of a diverse range of stable pentacovalent phosphoranes in good yields based on the benzooxaphosphole system.
Trinadh Kaicharla, Manikandan Thangaraj, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 1728-1731, Published: 21 March 2014 American Chemical Society (ACS)
Transition-metal-free multicomponent reactions involving arynes and isocyanides with either CO2 or H2O have been reported. With CO2 as the third component, the reactions resulted in the formation of N-substituted phthalimides. The utility of water as the third component furnished benzamide derivatives in moderate to good yields. These reactions took place under mild conditions with broad scope.
Sachin Suresh Bhojgude, Trinadh Kaicharla, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 5452-5455, Published: 1 November 2013 American Chemical Society (ACS)
The highly monoselective N-arylation of aromatic tertiary amines using a transition-metal-free approach using arynes has been developed. The reaction afforded functionalized diaryl amines in moderate to excellent yield. High levels of functional group compatibility especially with halogen containing substrates, dyes and donor-acceptor systems, and high yields of products are the notable features of the present reaction.
Santhivardhana Reddy Yetra, Trinadh Kaicharla, Sunita S. Kunte, Rajesh G. Gonnade, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 5202-5205, Published: 18 October 2013 American Chemical Society (ACS)
N-Heterocyclic carbene (NHC)-catalyzed highly enantioselective lactonization of modified enals with enolizable aldehydes, proceeding via the α,β-unsaturated acylazolium intermediates, is reported. The reaction results in the asymmetric synthesis of synthetically important 4,5-disubstituted dihydropyranones.
Trinadh Kaicharla, Santhivardhana Reddy Yetra, Tony Roy, and Akkattu T. Biju
Green Chemistry, ISSN: 14639262, eISSN: 14639270, Pages: 1608-1614, Published: June 2013 Royal Society of Chemistry (RSC)
A facile, atom-economic and environmentally-benign protocol for the synthesis of biologically important oxindole derivatives in high yields has been demonstrated by employing isatins as carbonyl compound surrogates in a Passerini reaction carried out under solvent-free conditions. Moreover, electron-deficient phenols can also be used as the acid component in this reaction. In addition, the synthetic utility of the present methodology was examined by the one-pot synthesis of oxindoles with a free –OH group at the benzylic position.
Trinadh Kaicharla, Sachin Suresh Bhojgude, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 6238-6241, Published: 21 December 2012 American Chemical Society (ACS)
A new protocol for the efficient Diels-Alder reaction of 1,2-benzoquinones with arynes is reported. The aryne generated by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates undergoes a facile Diels-Alder reaction with 1,2-benzoquinones, affording the dioxobenzobicyclooctadienes in moderate to excellent yields. In addition, this methodology has been applied to the one-pot synthesis of benzoquinoxalinobarrelene and naphthalene derivatives.
Sachin Suresh Bhojgude, Trinadh Kaicharla, Anup Bhunia, and Akkattu T. Biju
Organic Letters, ISSN: 15237060, eISSN: 15237052, Pages: 4098-4101, Published: 17 August 2012 American Chemical Society (ACS)
A high-yielding, versatile and practical Diels-Alder reaction of pentafulvenes with arynes under mild reaction conditions is reported. The aryne generated by the fluoride induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates undergoes efficient cycloaddition with 6-substituted and 6,6-disubstituted pentafulvenes leading to the formation of benzonorbornadiene derivatives.