@unpublished{pittir21714, month = {September}, title = {CHEMISTRY AND APPLICATIONS OF N-HETEROCYCLIC CARBENE BORANES}, author = {Xiangcheng Pan}, year = {2014}, keywords = {NHC, carbene, borane, radical}, url = {http://d-scholarship-dev.library.pitt.edu/21714/}, abstract = {Chemistry and applications of N-heterocyclic carbene borane complex are demonstrated. Chapter 1 describes and introduces the background of NHC-boranes. Chapter 2 demonstrates the discovery and studies of thiol-catalyzed radical reduction reactions of alkyl and aryl halides with NHC-boranes. The radical reductive cyclization reactions with NHC-boranes were also investigated. These reactions occur by a polarity-reversal process, where thiol is the polarity-reversal catalysis. Chapter 3 describes the development and preparative experiments of first homolytic substitution reactions of NHC-boryl radicals at divalent atoms such as sulfur and selenium. The primary reaction products of heterocycle disulfides undergo a 1,3-boryl shift from S to N to give new class of stable NHC-boranes with B-N heterocycles bonds. Chapter 4 describes the discovery that disulfides (RSSR), NHC-boryl mono- (NHC-BH2SR) and bis-sulfides (NHC-BH(SR)2) serve as both radical initiators and precatalysts in the radical reductions and reductive cyclizations with NHC-boranes. These reactions are also believed to occur by the polarity reversal catalysis mechanism. Chapter 5 describes the thiolation reactions with new synthesized NHC-boryl sulfides and ?amido complexes. Chapter 6 introduces iodine-activated hydroboration and preliminary results of direct hydroboration. } }