@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 {42441, title = {Diels-alder reaction of tropones with arynes: synthesis of functionalized benzobicyclo[3.2.2]nonatrienones}, journal = {Journal of Organic Chemistry}, volume = {79}, year = {2014}, month = {APR}, pages = {4757{\textendash}4762}, abstract = {

A new procedure for the mild, practical, and scalable Diels{\textendash}Alder reaction of tropones with arynes is reported. Differently substituted tropones undergo selective [4 + 2] cycloaddition with arynes generated in situ by the fluoride-induced 1,2-elimination of 2-(trimethylsilyl)aryl triflates, allowing the formation of functionalized benzobicyclo[3.2.2]nonatrienone derivatives in moderate to good yields. In addition, the photophysical properties of the cycloadducts are presented.

}, doi = {10.1021/jo500819w}, author = {Thangaraj, Manikandan and Bhojgude, Sachin Suresh and Bisht, Rajesh H. and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {42432, title = {Diastereoselective synthesis of cyclopentanone-fused spirooxindoles by N-heterocyclic carbene-catalyzed homoenolate annulation with isatilidenes}, journal = {Organic Chemistry Frontiers}, volume = {2}, year = {2015}, month = {SEP}, pages = {1584-1588}, abstract = {

N-Heterocyclic carbene (NHC)-catalyzed formal [3 + 2] annulation of α,β-unsaturated aldehydes with N-substituted isatilidenes resulting in the diastereoselective synthesis of cyclopentanone-fused spirooxindoles is demonstrated. Mechanistically, the reaction proceeds via the generation of homoenolate equivalent intermediates from NHC and enals, which on interception with isatilidenes afford spiroheterocyclic compounds bearing an all-carbon quaternary spiro-center in moderate to good yields and generally with high diastereoselectivity. Moreover, the functionalization of the spirooxindoles as well as the initial studies on the enantioselective version of this reaction are presented.

}, doi = {10.1039/C5QO00242G}, author = {Patra, Atanu and Bhunia, Anup and Yetra, Santhivardhana Reddy and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {48040, title = {Dynamic kinetic resolution of gamma,gamma-disubstituted indole 2-carboxaldehydes via NHC-Lewis acid cooperative catalysis for the synthesis of tetracyclic epsilon-lactones}, volume = {13}, year = {2022}, month = {OCT}, pages = {11513-11518}, type = {Article}, abstract = {

The ubiquity of epsilon-lactones in various biologically active compounds inspired the development of efficient and enantioselective routes to these target compounds. Described herein is the enantioselective synthesis of indole-fused epsilon-lactones by the N-heterocyclic carbene (NHC)-Lewis acid cooperative catalyzed dynamic kinetic resolution (DKR) of in situ generated gamma,gamma-disubstituted indole 2-carboxaldehydes. The Bi(OTf)(3)-catalyzed Friedel-Crafts reaction of indole-2-carboxaldehyde with 2-hydroxy phenyl p-quinone methides generates gamma,gamma-disubstituted indole 2-carboxaldehydes, which in the presence of NHC and Bi(OTf)(3) afforded the desired tetracyclic epsilon-lactones in up to 93\% yield and \>99 : 1 er. Moreover, preliminary studies on the mechanism of this formal [4 + 3] annulation are also provided.

}, issn = {2041-6520}, doi = {10.1039/d2sc03745a}, author = {Balanna, Kuruva and Barik, Soumen and Shee, Sayan and Gonnade, Rajesh G. and Biju, Akkattu T.} }