@article {42471, title = {1,4-Dipolar cycloaddition in organic synthesis: a facile route to isoquinoline fused heterocycles}, journal = {Arkivoc}, volume = {2005}, year = {2005}, month = {JAN}, pages = {178-188}, type = {Article}, abstract = {

The three component condensation reactions involving isoquinoline, dimethyl acetylenedicarboxylate and carbonyl dipolarophiles such as o- and p-benzoquinones and Nsubstituted isatins constitute a one-pot synthesis of a variety of [1,3]oxazino isoquinoline derivatives via 1,4-dipolar cycloaddition.

}, author = {Nair, Vijay and Sreekanth, Anakkalil R. and Abhilash, N. and Biju, Akkattu T. and Varma, Luxmi and Viji, Sreemathi and Mathew, Saumini} } @article {42470, title = {One pot four component reaction of isocyanides, dimethyl acetylenedicarboxylate and cyclobutene-1,2-diones: synthesis of spiro heterocycles}, journal = {Tetrahedron Letters}, volume = {48}, year = {2005}, month = {JAN}, pages = {1337{\textendash}1339}, abstract = {

Isocyanides, dimethyl acetylenedicarboxylate, and cyclobutene-1,2-diones react in one-pot to afford novel spirocyclic compounds with double insertion of the isocyanide.

}, doi = {10.1016/j.tetlet.2004.12.117.}, author = {Nair, Vijay and Menon, Rajeev S. and Deepthi, Ani B. and Devi, Rema and Biju, Akkattu T.} } @article {42472, title = {Reaction of diaryl-1,2-diones with triphenylphosphine and diethyl azodicarboxylate leading to N, N-dicarboethoxy monohydrazones via a novel rearrangement}, journal = {Organic Letters}, volume = {7}, year = {2005}, month = {MAY}, pages = {2121{\textendash}2123}, abstract = {

A mechanistically novel reaction of diaryl-1,2-diones with diethyl azodicarboxylate and triphenylphosphine to afford N,N-dicarboethoxy monohydrazones is described. The reaction proceeds via a nitrogen to nitrogen migration of a carboethoxy group.

}, doi = {10.1021/ol050403+}, author = {Nair, Vijay and Biju, Akkattu T. and Abhilash, K. G. and Menon, Rajeev S. and Eringathodi, Suresh} } @article {42473, title = {Reaction of huisgen zwitterion with 1,2-benzoquinones and isatins: expeditious synthesis of dihydro-1,2,3-benzoxadiazoles and spirooxadiazolines}, journal = {Organic Letters}, volume = {7}, year = {2005}, month = {OCT}, pages = {5139{\textendash}5142}, type = {Article}, abstract = {

The zwitterionic intermediate generated from dialkyl azodicarboxylate and triphenylphosphine on reaction with 3-methoxy-1,2-benzoquinones afforded dihydro-1,2,3-benzoxadiazoles. N-Substituted isatins furnished spirooxadiazolines under similar conditions.

}, doi = {10.1021/ol051956n}, author = {Nair, Vijay and Biju, Akkattu T. and Vinod, A. V. and Eringathodi, Suresh} } @article {42469, title = {DMAP-catalyzed reaction of beta-ketoesters and dimethyl acetylenedicarboxylate: an efficient synthesis of polysubstituted benzenes and biaryls}, journal = {Tetrahedron}, volume = {62}, year = {2006}, month = {SEP}, pages = {10136{\textendash}10140}, type = {Article}, abstract = {

A DMAP catalyzed tandem addition{\textendash}cyclization{\textendash}dehydration sequence involving dimethyl acetylenedicarboxylate and β-ketoesters leading to polysubstituted benzene/biaryl derivatives is presented.

}, doi = {10.1016/j.tet.2006.08.031}, author = {Nair, Vijay and Vidya, N. and Biju, Akkattu T. and Deepthi, Ani B. and Abhilash, K. G. and Eringathodi, Suresh} } @article {42468, title = {Engaging zwitterions in carbon-carbon and carbon-nitrogen bond- forming reactions: a promising synthetic strategy}, journal = {Accounts of Chemical Research}, volume = {39}, year = {2006}, month = {JUN}, pages = {520{\textendash}530}, type = {Article}, abstract = {

An Account of carbon-carbon and carbon-nitrogen bond-forming reactions mediated by zwitterions generated by the addition of organic nucleophiles to activated unsaturated systems highlighting their synthetic potential is presented.

}, doi = {10.1021/ar0502026}, author = {Nair, Vijay and Menon, Rajeev S. and Sreekanth, A. R. and Abhilash, N. and Biju, Akkattu T.} } @article {42467, title = {Novel synthesis of highly functionalized pyrazolines and pyrazoles by triphenylphosphine mediated reaction of dialkyl azodicarboxylate with allenic esters}, journal = {Organic Letters}, volume = {8}, year = {2006}, month = {MAY}, pages = {2213{\textendash}2216}, type = {Article}, abstract = {

Reaction of the Huisgen zwitterion, derived from triphenylphosphine and dialkyl azodicarboxylate, with allenic esters affords highly functionalized pyrazolines and pyrazoles. The crystal structure of pyrazoline derivative 7a showed extensive C-H{\textperiodcentered}{\textperiodcentered}{\textperiodcentered}O interactions. Pyrazole formation proceeds via a novel nitrogen to carbon migration of the carboalkoxy group.

}, doi = {10.1021/ol0604623}, author = {Nair, Vijay and Biju, Akkattu T. and Mohanan, Kishor and Eringathodi, Suresh} } @article {42465, title = {Efficient higher-order cycloaddition reactions of 8,8-dicyanoheptafulvenes with dienes}, journal = {Synthesis-Stuttgart }, year = {2007}, month = {JUN}, pages = {1833-1836}, type = {Article}, abstract = {

The cycloaddition reactions of 8,8-dicyanoheptafulvene with electron-rich dienes afforded the higher order cycloaddition products in excellent yields. With cyclic dienes as well as dimeth-oxybutadiene the [8+2] adducts were obtained exclusively. With methyl- and dimethylbutadienes the [6+4] adducts were the only products isolated.

}, keywords = {cycloadditions - bicyclic compounds - polycycles - di-cyanoheptafulvene - tetrahydroazulenes}, doi = {10.1055/s-2007-983711}, author = {Nair, Vijay and Gopalakrishnan Abhilash, K. and Biju, Akkattu T. and Eringathodi, Suresh} } @article {42463, title = {Novel reaction of the {\textquotedblleft}huisgen zwitterion{\textquotedblright} with chalcones and dienones: an efficient strategy for the synthesis of pyrazoline and pyrazolopyridazine derivatives}, journal = {Angewandte Chemie-International Edition}, volume = {46}, year = {2007}, month = {MAR}, pages = {2070{\textendash}2073}, type = {Article}, abstract = {

Two unexpected transformations: The reaction of the Huisgen zwitterion derived from triphenylphosphane and diisopropyl azodicarboxylate (DIAD) with chalcones affords functionalized pyrazolines. In contrast, the reaction with dienones affords pyrazolopyridazines, presumably by Diels{\textendash}Alder reaction of the initially formed pyrazoline with excess DIAD (see scheme).

}, keywords = {chalcones; nitrogen heterocycles; pyrazolines; synthetic methods; zwitterions}, doi = {10.1002/anie.200604025}, author = {Nair, Vijay and Biju, Akkattu T. and Mathew, Smitha C. and Eringathodi, Suresh} } @article {42462, title = {Reaction of huisgen zwitterion with diaryl-1,2-diones and ketones: an efficient protocol for carbon-nitrogen bond formation}, journal = {Synthesis-Stuttgart}, year = {2007}, month = {JAN}, pages = {697-704}, type = {Article}, abstract = {

The reaction of Huisgen zwitterion, derived from triphenylphosphine and dialkyl azodicarboxylate, with diaryl-1,2-diones afforded N,N-dicarboalkoxy monohydrazones via a mechanistically novel rearrangement. Cyclic and acyclic ketones furnished vinyl hydrazinedicarboxylates under similar conditions.

}, keywords = {betaines - diazo compounds - hydrazones - ketones - rearrangements}, doi = {10.1055/s-2007-965910}, author = {Nair, Vijay and Biju, Akkattu T. and Mathew, Smitha C.} } @article {42466, title = {Reaction of tpp-azodicarboxylate zwitterions and aldehydes: unprecedented synthesis of acyl carbamates}, journal = {Tetrahedron Letters}, volume = {48}, year = {2007}, month = {OCT}, pages = {9018{\textendash}9020}, type = {Article}, abstract = {

An efficient synthesis of acyl carbamates from aryl aldehydes by the reaction of triphenylphosphine and dialkyl azoesters is described.

}, doi = {10.1016/j.tetlet.2007.10.092}, author = {Nair, Vijay and Mathew, Smitha C. and Biju, Akkattu T. and Eringathodi, Suresh} } @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 {42461, title = {Carbon-nitrogen bond-forming reactions of dialkyl azodicarboxylate: a promising synthetic strategy}, journal = {Chemistry an Asian Journal}, volume = {3}, year = {2008}, month = {MAY}, pages = {810{\textendash}820}, type = {Article}, abstract = {

Azodicarboxylates have found applications in electrophilic amination reactions and in pericyclic reactions. The nucleophilic trigger in Mitsunobu reactions, that is, the zwitterion formed from triphenylphosphine and dialkyl azodicarboxylate, has been utilized recently in various heterocyclic constructions. This Focus Review summarizes the potential utility of azodicarboxylates in various carbon{\textendash}nitrogen bond-forming reactions.

}, keywords = {amination reactions; azodicarboxylates; C[BOND]N bond formation; heterocycles; Huisgen zwitterion}, doi = {10.1002/asia.200700341}, author = {Nair, Vijay and Biju, Akkattu T. and Mathew, Smitha C. and Pattoorpadi, Beneesh Babu} } @article {42460, title = {Reaction of huisgen zwitterion with diaryl ketones leading to the facile synthesis of mono- and bis(alkoxycarbonyl)hydrazones}, journal = {Synthesis-Stuttgart}, year = {2008}, month = {MAR}, pages = {1078-1084}, abstract = {

The Huisgen zwitterion, generated from triphenylphosphine and dialkyl azodicarboxylates, afforded upon reaction with diaryl ketones both mono- and bis(alkoxycarbonyl)hydrazones, depending on the reaction conditions.

}, doi = {10.1055/s-2008-1032125}, author = {Nair, Vijay and Mathew, Smitha C. and Biju, Akkattu T. and Eringathodi, Suresh} } @article {42455, title = {Reactions of morita-baylis-hillman acetates with huisgen zwitterions: a novel strategy for the synthesis of ?-amino acid derivatives}, journal = {Synthesis}, year = {2009}, month = {APR}, pages = {1829{\textendash}1833}, abstract = {

The reaction of Huisgen Zwitterion with Morita{\textendash}Baylis{\textendash} Hillman acetates afforded b-amino acid derivatives.

}, keywords = {b-amino acid, Huisgen zwitterion, Morita{\textendash}Baylis{\textendash}Hillman acetate}, doi = {10.1055/s-0028-1088063}, author = {Jose, Anu and Paul, Rony Rajan and Mohan, Resmi and Mathew, Smitha C. and Biju, Akkattu T. and Eringathodi, Suresh and Nair, Vijay} } @article { ISI:000295921500010, title = {Employing homoenolates generated by NHC catalysis in carbon-carbon bond-forming reactions: state of the art}, journal = {Chemical Society Reviews}, volume = {40}, number = {11}, year = {2011}, month = {JUL}, pages = {5336-5346}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Homoenolate is a reactive intermediate that possesses an anionic or nucleophilic carbon beta to a carbonyl group or its synthetic equivalent. The recent discovery that homoenolates can be generated from alpha,beta-unsaturated aldehydes via N-Heterocyclic Carbene (NHC) catalysis has led to the development of a number of new reactions. A majority of such reactions include the use of carbon-based electrophiles, such as aldehydes, imines, enones, dienones etc. resulting in the formation of a variety of annulated as well as acyclic products. The easy availability of chiral NHCs has allowed the development of very efficient enantioselective variants of these reactions also. The tolerance showed by NHCs towards magnesium and titanium based Lewis acids has been exploited in the invention of cooperative catalytic processes. This tutorial review focuses on these and other types of homoenolate reactions reported recently, and in the process, updates the previous account published in 2008 in this journal.

}, issn = {0306-0012}, doi = {10.1039/c1cs15139h}, author = {Nair, Vijay and Menon, Rajeev S. and Biju, Akkattu T. and Sinu, C. R. and Paul, Rony Rajan and Jose, Anu and Sreekumar, Vellalath} } @article { ISI:000299176700007, title = {1,2-Benzoquinones in Diels-Alder reactions, dipolar cycloadditions, nucleophilic additions, multicomponent reactions and more}, journal = {Chemical Society Reviews}, volume = {41}, number = {3}, year = {2012}, month = {SEP}, pages = {1050-1059}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A brief account of the recent developments in the chemistry of 1,2-benzoquinones is presented in this tutorial review. The title compounds exhibit commendable versatility in both Diels-Alder and dipolar cycloaddition reactions. They have also been employed as electrophilic reaction partners in nucleophile-triggered catalytic processes and related multicomponent reactions. These, along with other reactions described here, lead to the synthesis of densely functionalised carbocyclic and heterocyclic frameworks that are otherwise difficult to access.

}, issn = {0306-0012}, doi = {10.1039/c1cs15186j}, author = {Nair, Vijay and Menon, Rajeev S. and Biju, Akkattu T. and Abhilash, K. G.} } @article { ISI:000358219300005, title = {Recent advances in employing homoenolates generated by N-heterocyclic carbene (NHC) catalysis in carbon-carbon bond-forming reactions}, journal = {Chemical Society Reviews}, volume = {44}, number = {15}, year = {2015}, month = {MAY}, pages = {5040-5052}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

The use of NHCs for generating homoenolate species has gained widespread popularity in recent years. A number of highly stereoselective processes of NHC-homoenolates have emerged. Homoenolate reactions have also been employed as key steps in the total synthesis of a number of natural products. The use of compatible co-catalysts, improved NHC-catalyst design and the use of novel precursors for homoenolate generation are among the major developments in this area that were disclosed recently. This tutorial review organises and presents the advancements in this rapidly growing area of catalysis and in the process updates a previous account published in 2011 in this journal.

}, issn = {0306-0012}, doi = {10.1039/c5cs00162e}, author = {Menon, Rajeev S. and Biju, Akkattu T. and Nair, Vijay} } @article { ISI:000371566100001, title = {Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions}, journal = {Beilstein Journal of Organic Chemistry}, volume = {12}, year = {2016}, month = {MAR}, pages = {444-461}, publisher = {BEILSTEIN-INSTITUT}, address = {TRAKEHNER STRASSE 7-9, FRANKFURT AM MAIN, 60487, GERMANY}, abstract = {

N-Heterocyclic carbenes (NHCs) have emerged as a powerful class of organocatalysts that mediate a variety of organic transformations. The Benzoin reaction constitutes one of the earliest known carbon-carbon bond-forming reactions catalysed by NHCs. The rapid growth of NHC catalysis in general has resulted in the development of a variety of benzoin and benzoin-type reactions. An overview of such NHC-catalysed benzoin reactions is presented.

}, keywords = {acyloin reaction, benzoin reaction, N-heterocyclic carbenes, organocatalysis, umpolung}, issn = {1860-5397}, doi = {10.3762/bjoc.12.47}, author = {Menon, Rajeev S. and Biju, Akkattu T. and Nair, Vijay} } @article {42420, title = {Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions (vol 12, pg 444, 2016)}, journal = {Beilstein Journal of Organic Chemistry}, volume = {12}, year = {2016}, month = {OCT}, pages = {2124-2124}, keywords = {acyloin reaction; benzoin reaction; N-heterocyclic carbenes; organocatalysis; umpolung}, doi = {10.3762/bjoc.12.201}, author = {Menon, Rajeev S. and Biju, Akkattu T. and Nair, Vijay} }