Synthesis And Catalytic Property Of 1,2-Azaborolyl And Boratabenzene Rhodium Complexes And Reactivity Of 1,2-Azaborolyl Ruthenium Vinylidene Complexes

The borataheterocycles 1,2-azaborolyl?Ab?and boratabenzene?Bb?have been investigated as effective potential replacement ligands for cyclopentadienyl?Cp?group in various transition-metal complexes.However,rhodium complexes with Ab or Bb ligand are still very rare and only limited to several scattering examples.In particular,half-sandwich Rh???complexes of Ab or Bb have never been reported so far.In view of the versatile catalytic properties of Cp-based half-sandwich Rh?III?complexes,the studies in this dissertation explored the synthesis and catalytic properties of 1,2-azaborolyl and boratabenzene Rh???omplexes.In addition,as part of interest in synthesis and reactivity of half-sandwich ruthenium complexes of this two borataheterocycle ligands,the reactivity of 1,2-Azaborolyl ruthenium vinylidene complexes have also been investigated in this study.This thesis consists of the following five chapters.Chapter 1 briefly introduces the chemistry of 1,2-azaborolyl and boratabenzene,as well as the progress on the synthesis and reactivity of rhodium complexes with this two boratahetercycle ligands.The catalytic properties of Cp-based half-sandwich rhodium complexes are also briefly reviewed.In addition,the research objectives of this dissertation are presented as well.Chapter 2 describes the synthesis of 1,2-azaborolyl rhodium complexes and their catalytic activity for the dimerization of terminal alkynes.The reactions of[Ab-C?CPh]Li with[RhCl?COD?]2 and RhCl?PPh₃?3 lead to the formation of?Ab-C?CPh?Rh?COD??2-14?and?Ab-C?CPh?Rh?PPh₃?₂?2-18?.The latter is oxidized by I₂ and generates?Ab-?CPh?RhI2?PPh₃??2-19?.?Ab-C?CPh?RhI2?PPh₃??2-19?effectively catalyzes the dimerization of aliphatic alkynes to give?E?-enynes in high regioselectivity,especially for the alkynes with bulky substituents such as 3,3-dimethyl-but-1-yne and trimethylsilylacetylene which can produce?E?-enynes exclusively.Chapter 3 describes the synthesis of borataebnzene complexes and their catalytic activity for ?-selective oxidative Heck-type coupling of vinyl acetate via C-Hactivation.The reactions of[Bb-OEt]Na,[Bb-NPh₂]K with[RhCl?COD?]2 lead to formation?Bb-OEt?Rh?COD??3-14?and?Bb-NPh₂?Rh?COD??3-15?.The latter is oxidized by I₂ and generates[?Bb-NPh₂?RhI2]2?3-16?.3-16 is an effective catalyst for the C-H olefination of acetanilides via ?-selective oxidative heck-type coupling with vinyl acetate.Various acetanilide substrates bearing substituents with different electronic and steric properties have been investigated to explore the effect of the reaction.Moreover,the activity of the new catalyst for this reaction is compared with our preveiouly reported reaction catalyzed by[Cp*RhCl₂]2.Chapter 4 is about the reactivity of 1,2-azaborolyl vinylidene ruthenium complexes.In NMR tube,we detected trace Ru?C?CPh??CS??S₂COMe??PPh₃?₂?4-12?by the reaction of?Ab-C?CPh?RuCl?=C=CPh??PPh₃??4-10?with CS₂ in the presence of NaOMe.The reaction of(?Ab-C?CPh?RuCl?=C?CBut??PPh₃??4-11?with CS₂ in the presence of NEt₃ lead to formation?Ab-C?CPh?Ru?S₂CC?CBut??PPh₃??4-13?.In addition,4-13 can be alternatively prepared from the one pot reaction of?Ab-C?CPh?RuCl?PPh₃?₂?4-8?with CS₂ and 3,3-dimethyl-but-1-yne in the presence of NEt3.Further on,the reaction of 4-11 with Ph₂P-C?CPh has been investigated,which leads to the formation of?Ab-C?CPh?RuCl?Ph₂P-C?CPh?2?4-14?,and 4-14 can also be produced from the reaction of 4-8 with Ph₂P-C?CPh.Chapter 5 summarizes the research work of this dissertation.