?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F9680%2F&rft.title=ALKENYL+IMINIUM+ION+IN+DIELS-ALDER+REACTION%3A+SYNTHESIS+OF+HIGHLY+SUBSTITUTED+N-HETEROCYCLES&rft.creator=Sarkar%2C+Nihar+Ranjan&rft.description=Heterocyclic+structures+are+critical+components+of+an+extensive+collection+of+chemotherapeutic+agents%2C+either+in+service+or+under+development%2C+for+treating+numerous+human+illnesses.+As+a+result%2C+reaction+technologies+for+heterocycle+construction%2C+in+the+context+of+both+target-+and+diversity-oriented+synthesis%2C+enjoy+a+particularly+prominent+role+in+medicinal+chemistry.+Amongst+all+the+C-C+bond+forming+reactions%2C+the+classic+Diels-Alder+cycloaddition+remains+one+of+the+most+powerful+transformations+in+organic+chemistry+especially+for+the+formation+of+heterocyclic+structures.+Herein%2C+we+report+a+new+methodology+based+on+inverse+electron+demand+Diels-Alder+reaction+utilizing+reactive+%22N-alkenyl+iminium+ion%22+and+a+suitable+dienophile+for+the+stereoselective+synthesis+of+substituted+piperidine+derivatives.+In+presence+of+a+suitable+Lewis+acid%2C+the+%22N-alkenyl+iminium+ion%22+is+generated+from+the+respective+enamine-aminal+derivative+in+situ+and+undergoes+Diels-Alder+reaction+with+a+dienophile+producing+a+highly+substituted+N-heterocycle+(piperidine+derivative)+in+one+step.An+efficient+transition+metal+catalyzed+isomerization+technique+for+the+synthesis+of+a+new+enamine-aminal+synthon+from+respective+N-allylamine+derivatives+has+been+developed.+Cationic+Ir-(COE)+complex%2C+a+potential+catalyst+for+ICR+chemistry%2C+was+used+for+the+isomerization+of+tosyl+protected+N-allylamine+derivatives+to+synthesize+N-tosyl-alkenyl+iminium+ion+precursor+in+high+geometrical+selectivity+and+quantitative+yield+whereas+carbamate+(or+amide)+protected+N-allylamine+derivatives+were+isomerized+with+good+E%2FZ+ratio+using+Grubbs+II.&rft.date=2010-01-28&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F9680%2F1%2FNiharSarkar_Thesis2.pdf&rft.identifier=++Sarkar%2C+Nihar+Ranjan++(2010)+ALKENYL+IMINIUM+ION+IN+DIELS-ALDER+REACTION%3A+SYNTHESIS+OF+HIGHLY+SUBSTITUTED+N-HETEROCYCLES.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++