01302nas a2200205   4500008004100000022001400041245013700055210006900192260011000261300001600371490000700387520043100394100002300825700003300848700001700881700002200898700002400920700002200944856013000966       2014                        eng d  a1359-734500aN-Heterocyclic carbene-catalyzed enantioselective synthesis of functionalized cyclopentenes via alpha,beta-unsaturated acyl azoliums0 aNHeterocyclic carbenecatalyzed enantioselective synthesis of fun  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT  a14539-145420 v503 a<p>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.</p>1 aMondal, Santigopal1 aYetra, Santhivardhana, Reddy1 aPatra, Atanu1 aKunte, Sunita, S.1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-enantioselective-synthesis-functionalized-cyclopentenes-001121nas a2200181   4500008004100000022001400041245013800055210006900193260000800262300001400270490000700284520042000291100003300711700002300744700002400767700002200791856012600813       2015                        eng d  a1523-706000aEnantioselective synthesis of functionalized pyrazoles by NHC-catalyzed reaction of pyrazolones with alpha,beta-unsaturated aldehydes0 aEnantioselective synthesis of functionalized pyrazoles by NHCcat  cMAR  a1417-14200 v173 a<p>The N-heterocyclic carbene (NHC)-organocatalyzed enantioselective annulation reaction of pyrazolones with alpha,beta-unsaturated aldehydes proceeding via the chiral alpha,beta-unsaturated acyl azolium intermediates under oxidative conditions is presented. The reaction afforded dihydropyranone-fused pyrazoles in moderate to good yields and good er values under operationally simple and base-free conditions.</p>1 aYetra, Santhivardhana, Reddy1 aMondal, Santigopal1 aSuresh, Eringathodi1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/enantioselective-synthesis-functionalized-pyrazoles-nhc-catalyzed-reaction-pyrazolones01234nas a2200181   4500008004100000245013800041210007000179260000800249300001400257490000700271520052900278100002300807700002300830700001700853700002400870700002200894856013600916       2015                        eng d00aN-Heterocyclic carbene-catalyzed diastereoselective synthesis of β-lactone-fused cyclopentanes using homoenolate annulation reaction0 aNHeterocyclic carbenecatalyzed diastereoselective synthesis of β  cMAY  a9559-95620 v513 a<p><span style="font-family: Arial;">NHC-catalyzed annulation of enals with 2-enoylpyridines or 2-enoylpyridine&nbsp;</span><em style="font-family: Arial;">N</em><span style="font-family: Arial;">-oxides leading to the diastereoselective synthesis of β-lactone-fused cyclopentanes is reported. The reaction proceeds&nbsp;</span><em style="font-family: Arial;">via</em><span style="font-family: Arial;">&nbsp;the generation of homoenolate equivalent intermediates and tolerates a broad range of functional groups.</span></p>1 aMukherjee, Subrata1 aMondal, Santigopal1 aPatra, Atanu1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-diastereoselective-synthesis-%CE%B2-lactone-fused-cyclopentanes01701nas a2200253   4500008004100000022001400041245011600055210006900171260007500240300001200315490000700327520074400334653002501078653002501103653002801128653002001156653002001176100003301196700002301229700002301252700002401275700002201299856012601321       2016                        eng d  a1433-785100aEnantioselective synthesis of spirocyclohexadienones by NHC-catalyzed formal [3+3] annulation reaction of enals0 aEnantioselective synthesis of spirocyclohexadienones by NHCcatal  aPOSTFACH 101161, 69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJAN  a268-2720 v553 a<p>The enantioselective synthesis of pyrazolone-fused spirocyclohexadienones was demonstrated by the reaction of alpha,beta-unsaturated aldehydes with alpha-arylidene pyrazolinones under oxidative N-heterocyclic carbene (NHC) catalysis. This atom-economic and formal [3+3] annulation reaction proceeds through a vinylogous Michael addition/spiroannulation/dehydrogenation cascade to afford spirocyclic compounds with an all-carbon quaternary stereocenter in moderate to good yields and excellent ee values. Key to the success of the reaction is the cooperative NHC-catalyzed generation of chiral alpha,beta-unsaturated acyl azoliums from enals, and base-mediated tandem generation of dienolate/enolate intermediates from pyrazolinones.</p>10aannulation reactions10aasymmetric catalysis10aN-heterocyclic carbenes10aorganocatalysis10aspiro compounds1 aYetra, Santhivardhana, Reddy1 aMondal, Santigopal1 aMukherjee, Subrata1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/enantioselective-synthesis-spirocyclohexadienones-nhc-catalyzed-formal-33-annulation-101131nas a2200157   4500008004100000245013200041210006900173260000800242490000700250520050200257100002200759700002300781700002400804700002200828856012300850       2017                        eng d00aBase-free and catalyst-free synthesis of functionalized dihydrobenzoxazoles via vinylogous carbonate to carbamate rearrangement0 aBasefree and catalystfree synthesis of functionalized dihydroben  cOCT0 v193 aAn unexpected, catalyst-free, and base-free intramolecular cyclization of N-aryloxyacrylate aldimines, under thermal conditions leading to the synthesis of functionalized dihydrobenzoxazoles, is reported. The reaction features a unique rearrangement of vinylogous carbonates to vinylogous carbamates resulting in a new carbon–oxygen and carbon–nitrogen bond construction. The reaction tolerates a broad range of functional groups and the desired products are formed in moderate to good yields.1 aDas, Tamal, Kanti1 aMondal, Santigopal1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/base-free-and-catalyst-free-synthesis-functionalized-dihydrobenzoxazoles-vinylogous01162nas a2200169   4500008004100000245011100041210007000152260000800222490000700230520051000237100002300747700002300770700002200793700002400815700002200839856013100861       2017                        eng d00aEnantioselective synthesis of functionalized β-lactones by NHC-catalyzed aldol lactonization of ketoacids0 aEnantioselective synthesis of functionalized βlactones by NHCcat  cAUG0 v823 aN-Heterocyclic carbene (NHC)-catalyzed intramolecular aldol lactonization of readily available ketoacids leading to the enantioselective synthesis of cyclopentane-fused β-lactones is presented. The reaction proceeds via the generation of NHC-bound enolate intermediates formed from the ketoacids in the presence of the peptide coupling reagent HATU and NHC generated from the chiral triazolium salt. The functionalized β-lactones are formed under mild conditions in high yields and enantioselectivities.1 aMondal, Santigopal1 aMukherjee, Subrata1 aDas, Tamal, Kanti1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/enantioselective-synthesis-functionalized-%CE%B2-lactones-nhc-catalyzed-aldol-lactonization01531nas a2200265   4500008004100000022001400041245010100055210006900156260000800225300001400233490000600247520065000253653002400903653001800927653001900945653001400964653002800978653002001006100002301026700002301049700002201072700002001094700002201114856012901136       2017                        eng d  a2155-543500aN-Heterocyclic carbene-catalyzed aldol-lactonization of ketoacids via dynamic kinetic resolution0 aNHeterocyclic carbenecatalyzed aldollactonization of ketoacids v  cJUN  a3995-39990 v73 a<p>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.</p>10aaldol lactonization10abeta-lactones10aDKR strategies10aketoacids10aN-heterocyclic carbenes10aorganocatalysis1 aMondal, Santigopal1 aMukherjee, Subrata1 aDas, Tamal, Kanti1 aGonnade, Rajesh1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-aldol-lactonization-ketoacids-dynamic-kinetic-resolution01315nas a2200181   4500008004100000245011300041210006900154260000800223300001400231490000700245520062900252100002300881700002300904700003300927700002400960700002200984856012701006       2017                        eng d00aOrganocatalytic enantioselective vinylogous michael-aidoi cascade for the synthesis of spirocyclic compounds0 aOrganocatalytic enantioselective vinylogous michaelaidoi cascade  cAUG  a4367-43700 v193 aEnantioselective synthesis of pyrazolone-fused spirocyclohexenols by the secondary amine-catalyzed cascade reaction of alpha,beta-unsaturated aldehydes with alpha-arylidene pyrazolinones is reported. This formal [3 + 3] organocascade reaction proceeds through a vinylogous Michael-aldol sequence to furnish the spiroheterocycles with three stereocenters including an all-carbon quaternary center in good yields and selectivities. The catalytic generation of alpha,beta-unsaturated iminium ions from enals and tandem dienolate/enolate formation from pyrazolinones are the key for the success of this spiroannulation reaction.1 aMondal, Santigopal1 aMukherjee, Subrata1 aYetra, Santhivardhana, Reddy1 aGonnade, Rajesh, G.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/organocatalytic-enantioselective-vinylogous-michael-aidoi-cascade-synthesis-spirocyclic01194nas a2200181   4500008004100000022001400041245012600055210006900181260000800250300001400258490000700272520051900279100002300798700001800821700002300839700002200862856012800884       2018                        eng d  a1523-706000aN-Heterocyclic carbene-catalyzed enantioselective synthesis of spiro-glutarimides via alpha,beta-unsaturated acylazoliums0 aNHeterocyclic carbenecatalyzed enantioselective synthesis of spi  cAUG  a4499-45030 v203 a<p>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.</p>1 aMondal, Santigopal1 aGhosh, Arghya1 aMukherjee, Subrata1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-enantioselective-synthesis-spiro-glutarimides-alphabeta01427nas a2200145   4500008004100000022003100041245007600072210006900148260001000217520086800227100002301095700003001118700002201148856011101170       2019                        eng d  aOnline ISBN: 978352780904200aN-heterocyclic carbene-catalyzed stetter reaction and related chemistry0 aNheterocyclic carbenecatalyzed stetter reaction and related chem  bWiley3 aThe 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.1 aMondal, Santigopal1 aYetra, Santhivardhana, R.1 aBiju, Akkattu, T.  uhttps://library.ncl.res.in/content/n-heterocyclic-carbene-catalyzed-stetter-reaction-and-related-chemistry