?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%2F25965%2F&rft.title=A+Formal+Vinyl+Sulfonyl+Nazarov+Cyclization+Accesses+9-(tosylmethyl)-2%2C3%2C4%2C4a-tetrahydro-1H-fluorenes&rft.creator=Berne%2C+Alexander+M&rft.description=During+the+course+of+a+proposed+route+to+synthesize+ladderane+lipids%2C+a+novel+one-pot+4%CF%80+electrocyclic+ring+opening+followed+by+a+Nazarov-type+4%CF%80+electrocyclization+reaction+was+discovered.+The+reaction+was+studied+further+due+to+its+potential+as+a+method+for+accessing+the+privileged+tetrahydrofluorene+scaffold+and+the+opportunities+for+further+functionalization+provided+by+the+allyl+sulfone+moiety.+Optimized+conditions+for+the+transformation+involved+refluxing+model+substrate+7-phenyl-8-tosylbicyclo%5B4.2.0%5Doct-6-ene+in+1%2C2-dichloroethane+for+3+h+to+generate+intermediate+(E)-1-((2-(cyclohex-1-en-1-yl)-2-phenylvinyl)sulfonyl)-4-methylbenzene.+Upon+cooling+to+room+temperature%2C+addition+of+1.2+equiv+iron(III)+chloride+promotes+cyclization+to+furnish+9-(tosylmethyl)-2%2C3%2C4%2C4a-tetrahydro-1H-fluorene+after+10+h+in+78%25+yield.+In+order+to+determine+the+effect+electronics+may+have+on+the+transformation%2C+functionality+was+introduced+onto+the+phenyl+ring.+While+no+noticeable+effect+was+observed+on+the+electrocyclic+ring+opening+step%2C+the+nature+of+the+substituents+significantly+affected+the+quantity+of+promoter+required+for+the+cyclization+step.+Although+a+superstoichiometric+amount+of+iron(III)+chloride+and+heat+was+required+with+an+electron+withdrawing+substituent+on+the+aryl+ring%2C+electron+donating+substituents+lowered+the+activation+barrier+to+cyclization+%E2%80%93+necessitating+only+catalytic+amounts+of+iron(III)+chloride+at+room+temperature.+This+transformation+represents+the+first+report+of+a+Nazarov+cyclization+with+a+vinyl+sulfone+on+the+central+carbon.+++&rft.date=2015-09-09&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%2F25965%2F1%2FFinal_MS_Thesis_Alex_Berne.pdf&rft.identifier=++Berne%2C+Alexander+M++(2015)+A+Formal+Vinyl+Sulfonyl+Nazarov+Cyclization+Accesses+9-(tosylmethyl)-2%2C3%2C4%2C4a-tetrahydro-1H-fluorenes.++Master's+Thesis%2C+University+of+Pittsburgh.++++(Unpublished)++