@article {42446, title = {Efficient diels-alder reaction of 1,2-benzoquinones with arynes and its utility in one-pot reactions}, journal = {Organic Letters}, volume = {14}, year = {2012}, month = {DEC}, pages = {6238{\textendash}6241}, abstract = {

A new protocol for the efficient Diels{\textendash}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{\textendash}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.

}, doi = {10.1021/ol302997q}, author = {Kaicharla, Trinadh and Bhojgude, Sachin Suresh and Biju, Akkattu T.} } @article {42447, title = {Practical and general diels-alder reaction of pentafulvenes with arynes}, journal = {Organic Letters}, volume = {14}, year = {2012}, month = {AUG}, pages = {4098{\textendash}4101}, abstract = {

A high-yielding, versatile and practical Diels{\textendash}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.

}, doi = {10.1021/ol301742k}, author = {Bhojgude, Sachin Suresh and Kaicharla, Trinadh and Bhunia, Anup and Biju, Akkattu T.} } @article { ISI:000326121700015, title = {Asymmetric N-heterocyclic carbene (NHC)-catalyzed annulation of modified enals with enolizable aldehydes}, journal = {Organic Letters}, volume = {15}, number = {20}, year = {2013}, month = {OCT}, pages = {5202-5205}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

N-Heterocyclic carbene (NHC)-catalyzed highly enantioselective lactonization of modified enals with enolizable aldehydes, proceeding via the alpha,beta-unsaturated acylazolium intermediates, is reported. The reaction results in the asymmetric synthesis of synthetically important 4,5-disubstituted dihydropyranones.

}, issn = {1523-7060}, doi = {10.1021/ol4026155}, author = {Yetra, Santhivardhana Reddy and Kaicharla, Trinadh and Kunte, Sunita S. and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article { ISI:000326615100015, title = {Employing arynes in transition-metal-free monoarylation of aromatic tertiary amines}, journal = {Organic Letters}, volume = {15}, number = {21}, year = {2013}, month = {NOV}, pages = {5452-5455}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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.

}, issn = {1523-7060}, doi = {10.1021/ol4029258}, author = {Bhojgude, Sachin Suresh and Kaicharla, Trinadh and Biju, Akkattu T.} } @article { ISI:000319405900025, title = {Engaging isatins in solvent-free, sterically congested passerini reaction}, journal = {Green Chemistry}, volume = {15}, number = {6}, year = {2013}, month = {APR}, pages = {1608-1614}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

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.

}, issn = {1463-9262}, doi = {10.1039/c3gc40454d}, author = {Kaicharla, Trinadh and Yetra, Santhivardhana Reddy and Roy, Tony and Biju, Akkattu T.} } @article { ISI:000341359000029, title = {Multicomponent reactions involving phosphines, arynes and aldehydes}, journal = {Chemical Communications}, volume = {50}, number = {77}, year = {2014}, month = {AUG}, pages = {11389-11392}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

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.

}, issn = {1359-7345}, doi = {10.1039/c4cc05420b}, author = {Bhunia, Anup and Kaicharla, Trinadh and Porwal, Digvijay and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {42443, title = {Practical synthesis of phthalimides and benzamides by a multicomponent reaction involving arynes, isocyanides, and CO2/H2O}, journal = {Organic Letters}, volume = {16}, year = {2014}, month = {MAR}, pages = {1728{\textendash}1731}, abstract = {

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.

}, doi = {10.1021/ol500403x}, author = {Kaicharla, Trinadh and Thangaraj, Manikandan and Biju, Akkattu T.} } @article {42417, title = {Aryne [2,3] stevens rearrangement}, journal = {Organic Letters}, volume = {18}, year = {2016}, month = {OCT}, pages = {5428-5431}, abstract = {

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.

}, doi = {10.1021/acs.orglett.6b02809}, author = {Roy, Tony and Thangaraj, Manikandan and Kaicharla, Trinadh and Kamath, Rupa V. and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article { ISI:000366864700011, title = {Employing carboxylic acids in aryne multicomponent coupling triggered by aziridines/azetidines}, journal = {Organic Chemistry Frontiers}, volume = {3}, number = {1}, year = {2016}, month = {NOV}, pages = {71-76}, publisher = {CHINESE CHEMICAL SOC}, address = {PO BOX 1-18, NANKANG, TAIPEI 115, TAIWAN}, abstract = {

The transition-metal-free aryne multicomponent coupling (MCC) involving carboxylic acids initiated by aziridines/azetidines has been reported. The use of aziridines as nucleophiles afforded N-aryl beta-amino alcohol derivatives and the application of azetidines as nucleophilic triggers furnished N-aryl gamma-amino alcohol derivatives in moderate to good yields. These reactions proceed under mild conditions and result in the formation of a new carbon-nitrogen bond and a new carbon-oxygen bond. The utility of carboxylic acids in aryne MCCs has been demonstrated, and the synthetic potential of phenols as acid surrogates in the present aryne MCCs has been realized.

}, issn = {2052-4129}, doi = {10.1039/c5qo00328h}, author = {Roy, Tony and Bhojgude, Sachin Suresh and Kaicharla, Trinadh and Thangaraj, Manikandan and Garai, Bikash and Biju, Akkattu T.} } @article {42428, title = {Lewis acid catalyzed selective reactions of donor-acceptor cyclopropanes with 2-naphthols}, journal = {Angewandte Chemie-International Edition}, volume = {55}, year = {2016}, month = {AUG}, pages = {10061-10064}, abstract = {

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 cyclo-propanes takes place, thus affording functionalized 2-naphthols. Both reactions furnished the target products in high regioselectivity and moderate to high yields.

}, keywords = {annulations; arenes; Lewis acids; reaction mechanisms; small ring systems}, doi = {10.1002/anie.201604373}, author = {Kaicharla, Trinadh and Roy, Tony and Thangaraj, Manikandan and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {43830, title = {AgOTf-catalyzed dehydrative [3+2] annulation of aziridines with 2-naphthols}, journal = {Chemical Communications}, volume = {53}, year = {2017}, month = {JUL}, pages = {8219-8222}, abstract = {The reaction of 2-naphthols with aziridines in the presence of AgOTf resulting in a dehydrative, formal [3+2] annulation is reported. The reaction allows the synthesis of functionalized benzoindolines, and tolerates a broad range of functional groups. A preliminary study on themechanism of this reaction indicates an SN1-type ring-opening of aziridines. This method is demonstrated for the one-pot synthesis of benzoindoles.}, doi = {10.1039/c7cc03425c}, author = {Kaicharla, Trinadh and Jacob, Anu and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {43907, title = {Metal-free, br{\o}nsted acid-catalyzed formal [3+2] annulation of quinone monoacetals with 2-naphthols}, journal = {Journal of Organic Chemistry}, volume = {82}, year = {2017}, month = {SEP}, type = {Article}, abstract = {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]benzofuranderivatives 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.}, doi = {10.1021/acs.joc.7b02033}, author = {Jacob, Anu and Roy, Tony and Kaicharla, Trinadh and Biju, Akkattu T.} }