@article { ISI:000344459400014, title = {N-Heterocyclic carbene-catalyzed enantioselective synthesis of functionalized cyclopentenes via alpha,beta-unsaturated acyl azoliums}, journal = {Chemical Communications}, volume = {50}, number = {93}, year = {2014}, month = {OCT}, pages = {14539-14542}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Highly enantioselective NHC-organocatalyzed synthesis of functionalized cyclopentenes proceeding via alpha,beta-unsaturated acyl azolium intermediates is reported. The organocascade reaction of modified enals with malonic ester derivatives having a gamma-benzoyl group involves the Michael-intramolecular aldol-beta-lactonization-decarboxylation sequence to deliver cyclopentenes in good yields and excellent ee values.

}, issn = {1359-7345}, doi = {10.1039/c4cc07433e}, author = {Mondal, Santigopal and Yetra, Santhivardhana Reddy and Patra, Atanu and Kunte, Sunita S. and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {42434, title = {N-Heterocyclic carbene-catalyzed diastereoselective synthesis of β-lactone-fused cyclopentanes using homoenolate annulation reaction}, journal = {Chemical Communications}, volume = {51}, year = {2015}, month = {MAY}, pages = {9559-9562}, abstract = {

NHC-catalyzed annulation of enals with 2-enoylpyridines or 2-enoylpyridine\ N-oxides leading to the diastereoselective synthesis of β-lactone-fused cyclopentanes is reported. The reaction proceeds\ via\ the generation of homoenolate equivalent intermediates and tolerates a broad range of functional groups.

}, doi = {10.1039/C5CC02960K}, author = {Mukherjee, Subrata and Mondal, Santigopal and Patra, Atanu and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {45769, title = {N-Heterocyclic carbene-catalyzed aldol-lactonization of ketoacids via dynamic kinetic resolution}, journal = {ACS Catalysis}, volume = {7}, year = {2017}, month = {JUN}, pages = {3995-3999}, type = {Article}, abstract = {

N-Heteroryclic carbene (NHC)-catalyzed enantioselective aldol lactonization of acyclic ketoacids, proceeding via dynamic kinetic resolution, is presented. The carbene generated from the chiral anninoinclanol-derived triazolium salt in the presence of LiCl was the key for the success of this transformation. The reaction allowed the diastereoselective and enantioselective synthesis of cyclopentane-fused beta-lactones having three contiguous stereocenters. The reaction products are shown to undergo substrate-controlled beta-lactone opening in the presence of amines to afford succinimide derivatives with four contiguous stereocenters.

}, keywords = {aldol lactonization, beta-lactones, DKR strategies, ketoacids, N-heterocyclic carbenes, organocatalysis}, issn = {2155-5435}, doi = {10.1021/acscatal.7b00681}, author = {Mondal, Santigopal and Mukherjee, Subrata and Das, Tamal Kanti and Gonnade, Rajesh and Biju, Akkattu T.} } @article {44644, title = {N-Heterocyclic carbene-catalyzed enantioselective synthesis of spiro-glutarimides via alpha,beta-unsaturated acylazoliums}, journal = {Organic Letters}, volume = {20}, year = {2018}, month = {AUG}, pages = {4499-4503}, abstract = {

NHC-catalyzed enantioselective [3 + 3] spiro-annulation of alpha,beta-unsaturated aldehydes with cyclic beta-ketoamides allowing the preparation of synthetically and biologically important spiro-glutarimide derivatives has been reported. The interception of the ketoamides with catalytically generated chiral alpha,beta-unsaturated acylazoliums proceeds in a Michael addition-intramolecular amidation pathway to deliver the spirocyclic products with good yield, diastereoselectivity, and enantioselectivity.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.8b01799}, author = {Mondal, Santigopal and Ghosh, Arghya and Mukherjee, Subrata and Biju, Akkattu T.} } @inbook {47494, title = {N-heterocyclic carbene-catalyzed stetter reaction and related chemistry}, booktitle = {N-Heterocyclic Carbenes in Organocatalysis}, year = {2019}, publisher = {Wiley}, organization = {Wiley}, chapter = {Chapter 3}, abstract = {The reversal of normal mode of reactivity (umpolung) of aldehydes is the most important application of N-heterocyclic carbenes (NHCs) in organocatalytic transformations. The benzoin condensation and the Stetter reaction are the two historic reactions where NHC reacts with aldehyde to generate acyl anion equivalent, which is subsequently intercepted with another molecule of carbonyl compound or Michael acceptor leading to the formation of the benzoin/Stetter products. The objective of this chapter is to provide an overview on NHC-catalyzed Stetter reaction and related chemistry. The development of various chiral catalysts for enantioselective intra- or intermolecular Stetter reaction has been described. Additionally, recent progress on NHC-catalyzed addition of aldehyde to unactivated multiple bonds in the hydroacylation reaction has been demonstrated.}, issn = {Online ISBN: 9783527809042}, doi = {10.1002/9783527809042.ch3}, author = {Mondal, Santigopal and Yetra, Santhivardhana R. and Biju, Akkattu T.} }