?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%2F33821%2F&rft.title=New+Reactions+with+N-Heterocyclic+Carbene+Boranes+and+Amidine+Boranes%2C+and+the+Study+of+Initiators+in+the+Radical+Hydrostannation+of+Propargyl+Silyl+Ethers&rft.creator=McFadden%2C+Timothy+R.&rft.description=The+development+of+new+reactions+of+N-heterocyclic+carbene+(NHC)+boranes+and+amidine-boranes+is+described.++Additionally%2C+the+mechanism+of+the+AIBN-+and+triethylborane-initiated+radical+hydrostannation+of+propargyl+silyl+ethers+is+studied.+%0D%0AChapter+1+describes+the+reaction+of+NHC-boranes+with+dimethyl+acetylenedicarboxylate+(DMAD)+to+form+alkenylboranes+and+boriranes.+These+products+arise+through+formal+single+and+double+trans-selective+hydroborations.+The+reaction+conditions+were+optimized+and+applied+to+produce+a+small+library+of+NHC-borane+derived+products.+Alkenylboranes+were+formed+as+the+major+product+from+the+reaction+of+N%2CN-dialkyl+NHC-boranes+with+DMAD%2C+while+boriranes+were+the+major+product+formed+from+the+reactions+of+N%2CN-diaryl+NHC-boranes.+Scope+and+limitation+studies+were+performed+to+show+that+borirane-formation+is+specific+to+the+reaction+of+NHC-boranes+and+borohydrides+with+DMAD.+Boriranes+were+not+formed+from+the+reaction+of+NHC-boranes+with+any+other+alkynes+or+from+the+reaction+of+amine-borane+complexes+with+DMAD.++Control+experiments+showed+that+the+products+could+not+be+interconverted.+The+mechanism+was+probed+by+deuterium-labeling+experiments.+%0D%0AChapter+2+describes+the+synthesis+and+characterization+of+amidine-boranes.++These+ligated+borane+complexes+can+be+prepared+in+good+yield+from+the+reaction+of++heterocyclic+amidines%2C+such+as+1%2C8-diazabicyclo(5.4.0)undec-7-ene+(DBU)+or+1%2C2-dimethylimidazole%2C+with+borane.+These+complexes+are+air-+and+water-stable+solids+at+room+temperature+and+do+not+decomplex+in+solution+at+elevated+temperature.+The+amidine-boranes+are+demonstrated+to+be+reactive+towards+acids+and+halogens%2C+in+addition+to+being+competent+aldehyde%2C+ketone%2C+and+imine+reducing+agents.+Compared+to+other+ligated+boranes%2C+DBU-borane+is+a+more+reactive+hydride+donor.+%0D%0AIn+Chapter+3%2C+the+azobisisobutyronitrile+(AIBN)-+and+triethylborane+(Et3B)%2Foxygen+(O2)-initiated+hydrostannation+of+propargyl+silyl+ethers+to+form+alkenylstannanes+is+studied+extensively.+When+Et3B%2FO2+is+used+to+initiate+the+reaction%2C+the+resulting+alkenylstannane+is+formed+with+high+Z-selectivity%2C+while+little+selectivity+is+observed+when+the+reaction+is+initiated+by+AIBN.+Recent+publications+asserted+that+the+difference+in+selectivity+is+derived+from+differing+reaction+mechanisms+of+the+two+initiators.+The+role+of+initiator%2C+temperature%2C+and+reaction+time+are+probed+to+demonstrate+that+both+AIBN+and+Et3B%2FO2+initiated+the+reaction+by+the+same+mechanism%2C+but+at+differing+efficiencies%2C+leading+to+different+product+ratios.&rft.date=2018-06-28&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%2F33821%2F1%2Ftrmcfadden_etd_2018_1.pdf&rft.identifier=++McFadden%2C+Timothy+R.++(2018)+New+Reactions+with+N-Heterocyclic+Carbene+Boranes+and+Amidine+Boranes%2C+and+the+Study+of+Initiators+in+the+Radical+Hydrostannation+of+Propargyl+Silyl+Ethers.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++