@article {42464, title = {Stereoselective synthesis of 3,4-trans-disubstituted γ-lactams by cerium(iv) ammonium nitrate mediated radical cyclization of cinnamamides}, journal = {Synthesis-Stuttgart}, year = {2007}, month = {MAR}, pages = {1179-1184}, type = {Article}, abstract = {

A facile synthesis of 3,4-trans-disubstituted γ-lactams was developed, consisting of the radical cyclization of cinnam-amides mediated by cerium(IV) ammonium nitrate. The single-electron-transfer (SET) reaction of the methoxystyrenyl moiety mediated by cerium(IV) ammonium nitrate gives rise to a cation radical, whose cyclization followed by reaction with oxygen and methanol generates 3,4-trans-disubstituted γ-lactams.

}, keywords = {cerium(IV) ammonium nitrate - intramolecular cyclization - cinnamamides - single electron transfer - γ-lactams}, doi = {10.1055/s-2007-965981}, author = {Nair, Vijay and Mohanan, Kishor and Suja, Tachapully D. and Biju, Akkattu T.} } @article {42459, title = {Switching the electron-donor properties of n-heterocyclic carbenes by a facile deprotonation strategy}, journal = {Chemistry an Asian Journal}, volume = {9}, year = {2009}, month = {DEC}, pages = {1786{\textendash}1789}, abstract = {

Flip the switch! The facile and distinct variation of the electronic properties of an N-heterocyclic carbene (NHC) ligand is reported. In this process, a simple deprotonation/protonation strategy can render the NHC to be an electron-poor or an electron-rich NHC ligand: one ligand, two electronic natures.

}, keywords = {carbenes; electronic properties; enolates; heterocycles; ligand design}, doi = {10.1002/asia.200900410}, author = {Biju, Akkattu T. and Hirano, Keiichi and Frohlich, Roland and Glorius, Frank} } @article {42451, title = {Synthesis and application of a chiral diborate}, journal = {Journal of Organic Chemistry}, volume = {76}, year = {2011}, month = {MAR}, pages = {2324{\textendash}2327}, abstract = {

A chiral diborate with different counterions is reported whose structure was unambiguously confirmed by X-ray analysis. This chiral dianion was used in the resolution of trans-1,2-diamines and also as a chiral shift reagent for NMR analysis of triphenylphosphonium salts.

}, doi = {10.1021/jo102559s}, author = {Loewer, Yvonne and Weiss, Christine and Biju, Akkattu T. and Frohlich, Roland and Glorius, Frank} } @article {42442, title = {Synthesis of functionalized coumarins and quinolinones by NHC-catalyzed annulation of modified enals with heterocyclic C-H acids}, journal = {Journal of Organic Chemistry}, volume = {79}, year = {2014}, month = {APR}, pages = {4245{\textendash}4251}, abstract = {

N-Heterocyclic carbene (NHC) catalyzed lactonization and lactamization of 2-bromoenals with heterocyclic C{\textendash}H acids proceeding via the α,β-unsaturated acyl azolium intermediates is reported. The reaction furnished coumarin- or quinolinone-fused lactone/lactam derivatives. In addition, results of the enantioselective version of this reaction using chiral NHC are presented.

}, doi = {10.1021/jo500693h}, author = {Yetra, Santhivardhana Reddy and Roy, Tony and Bhunia, Anup and Porwal, Digvijay and Biju, Akkattu T.} } @article { ISI:000364435000072, title = {Synthesis of N-aryl beta-amino alcohols by trifluoroacetic acid promoted multicomponent coupling of aziridines, arynes, and water}, journal = {Journal of Organic Chemistry}, volume = {80}, number = {21}, year = {2015}, month = {NOV}, pages = {11131-11137}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A transition-metal-free, three-component coupling involving N-substituted aziridines, arynes, and water promoted by trifluoroacetic acid (TFA) has been reported. The reaction furnished medicinally important N-aryl beta-amino alcohol derivatives in moderate to good yields. In addition, the use of azetidines in this reaction afforded N-aryl gamma-amino alcohol derivatives.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.5b01798}, author = {Roy, Tony and Baviskar, Dnyaneshwar R. and Biju, Akkattu T.} } @article {42430, title = {Selective synthesis of N-unsubstituted and N-arylindoles by the reaction of arynes with azirines}, journal = {Journal of Organic Chemistry}, volume = {81}, year = {2016}, month = {SEP}, pages = {8604-8611}, abstract = {

The transition-metal-free and temperature-dependent highly selective reaction of arynes with 2H-azirines allowing the synthesis of either N-unsubstituted or N-arylindoles has been developed. At 60 degrees C, arynes generated from 2-(trimethylsilyl)aryl triflates smoothly insert into 2H-azirines to form 2,3-diarylindoles with high selectivity. Interestingly, when the reaction was performed at -10 degrees C, the selectivity was switched to the formation of 1,2,3-triarylindoles in good yields.

}, doi = {10.1021/acs.joc.6b01472}, author = {Thangaraj, Manikandan and Bhojgude, Sachin Suresh and "Jain, Shailja" and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {42429, title = {Substrate-controlled selectivity switch in the three-component coupling involving arynes, aromatic tertiary amines, and CO2}, journal = {Organic Letters}, volume = {18}, year = {2016}, month = {OCT}, pages = {5424{\textendash}5427}, abstract = {

The transition-metal-free multicomponent coupling involving arynes, aromatic tertiary amines, and CO2\ is reported. The reaction exhibits switchable selectivity depending on the electronic nature of the aromatic amines used. With amines bearing electron-releasing/neutral groups as the nucleophilic trigger, the reaction afforded 2-arylamino benzoates via a nitrogen to oxygen alkyl group migration. Employing electron-deficient amines in the reaction furnished 2-aminoaryl benzoates proceeding via the aryl to aryl amino group migration resembling a Smiles rearrangement.

}, doi = {10.1021/acs.orglett.6b02845}, author = {Bhojgude, Sachin Suresh and Roy, Tony and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {42431, title = {Synthesis of 4H-chromenes by an unexpected, K3PO4-mediated intramolecular rauhut{\textendash}currier type reaction}, journal = {Organic \& Biomolecular Chemistry}, volume = {14}, year = {2016}, month = {APR}, pages = {5612-5616}, abstract = {

In an attempt to develop the umpolung of Michael acceptors using chalcones having an enoate moiety under N-heterocyclic carbene (NHC) catalysis, a K3PO4-mediated intramolecular Rauhut{\textendash}Currier type reaction was observed. This C(sp2){\textendash}C(sp2) coupling reaction afforded the biologically important 4H-chromenes in moderate to good yields. It is likely that the enol ether functionality acts as the nucleophilic trigger in this reaction.

}, doi = {10.1039/C6OB00654J}, author = {Bhunia, Anup and Yetra, Santhivardhana Reddy and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article { ISI:000379431000015, title = {Synthesis of functionalized amino epoxides by a three-component coupling involving aziridines, arynes and aldehydes}, journal = {Chemical Communications}, volume = {52}, number = {58}, year = {2016}, month = {JAN}, pages = {9044-9047}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A transition-metal-free three-component coupling involving N-substituted aziridines, arynes and aldehydes resulting in the formation of trisubstituted N-aryl alpha-amino epoxides has been demonstrated. The reaction likely proceeds via the highly strained cyclic nitrogen ylide intermediates generated from aziridines and arynes.

}, issn = {1359-7345}, doi = {10.1039/c6cc00057f}, author = {Roy, Tony and Thangaraj, Manikandan and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {43565, title = {Synthesis of functionalized β-keto arylthioethers by the aryne induced [2,3] Stevens rearrangement of allylthioethers}, journal = {Journal of Organic Chemistry}, volume = {82}, year = {2017}, month = {MAR}, pages = {4470{\textendash}4476}, type = {Article}, chapter = {4470{\textendash}4476}, abstract = {A mild and transition-metal-free synthesis of β-keto arylthioethers has been developed by the aryne triggered [2,3] Stevens rearrangement of allylthioethers. The key sulfur ylide intermediate for the rearrangement was formed by the S-arylation of allylthioethers with arynes generated from 2-(trimethylsilyl)aryl triflates using CsF. Later, the reaction products are converted into valuable heterocycles in two steps.}, doi = {10.1021/acs.joc.7b00479}, author = {Thangaraj, Manikandan and Gaykar, Rahul N. and Roy, Tony and Biju, Akkattu T.} } @article {44507, title = {Synthesis of 4-difluoromethylquinolines by NHC-catalyzed umpolung of imines}, journal = { Organic Letters}, volume = {20}, year = {2018}, month = {JAN}, pages = {1086{\textendash}1089}, type = {Journal Article}, abstract = {The N-heterocyclic carbene (NHC)-catalyzed umpolung of aldimines for the synthesis of 4-difluoromethylquinoline derivatives is reported. In the presence of NHCs, the intramolecular cyclization of aldimines bearing a moderately electron-poor double bond due to the presence of the -CF3 group likely proceeds via the intermediacy of the aza-Breslow intermediate. The key to the success of this aza-Stetter type transformation is the NHC generated from the bicyclic triazolium salt using DBU as the base.}, issn = {15237060}, doi = {10.1021/acs.orglett.7b04055}, author = {Patra, Atanu}, editor = {Gelat, Fabien} } @article {45507, title = {Synthesis of 2-Aryl naphthoquinones by the cross-dehydrogenative coupling involving an NHC-catalyzed endo-stetter reaction}, journal = {Journal of Organic Chemistry}, volume = {84}, year = {2019}, month = {JAN }, pages = {1103-1110}, type = {Article}, abstract = {

An N-heterocyclic carbene (NHC)-catalyzed intramolecular Stetter reaction proceeding via the endo-fashion was the key step for the transition-metal-free and mild cross-dehydrogenative coupling of 2-cinnamoyl benzal-dehydes allowing for the synthesis of 2-aryl naphthoquinones. In this transformation, the carbene generated from the triazolium salt using Na2CO3 catalyzes the intramolecular Stetter reaction, which was followed by air oxidation to reinstall the C-C double bond.

}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b02931}, author = {Ghosh, Arghya and Patra, Atanu and Mukherjee, Subrata and Biju, Akkattu T.} }