Study Of Frustrated Lewis Pair Catalyzed Hydragenation And Polymerization

The concept of "frustrated lewis pairs" ?FLPs? is that sterically encumbered Lewis acid and Lewis base are sterically precluded from forming classical adducts. The seminal work was reported that FLPs can activate hydrogen reversibly. The application of FLPs has been widely extended in different fields. Nearly ten years of development, FLPs was found to activate H₂, CO₂, N₂O, B-H bond, alkenes, alkynes, etc. In the field of polymer chemistry, FLPs can effect the rapid polymerization of polar vinyl monomers.Piperidines are very important moieties contained in a wide range of biologically active compounds, and numerous methodologies have been established for their synthesis. The catalytic hydrogenation of pyridines with H₂ undoubtedly provides a simple and straightforward approach for accessing piperidines, although it is essential to overcome some inherent challenges presented by catalyst deactivation and pyridine dearomatization. Various heterogeneous transition-metal catalysts and several homogeneous Rh, Ir, and Ru complexes have been studied for the direct hydrogenation of pyridines, but harsh reaction conditions and/or specific pyridines bearing activating groups are often required because of the low activity and selectivity of the catalysts. Herein we developed a new type of metal-free catalysts in order to achieve catalytic hydrogenation of simple pyridine derivatives by using small molecule hydrogen source ammonia borane.Although select phosphine/Al?C₆F₅?₃ pairs have been found to rapidly convert MMA and naturally renewable MBL and MMBL monomers into high MW polymers, controlled polymerization cannot be implemented by such FLPs catalytic system. As the aluminum atom restricts the lewis acid modification, the catalytic system is relatively monotonous. Utilizing borane as lewis acid will strongly expand FLPs catalytic system for not only enriching the types of lewis acid but also realizing the construction of chiral lewis acid. Futhermore we demonstrates that striking a fine balance between the electron-donating property, steric property, and stability of Lewid base is crucial for achieving a highly active and effective LPP system. Herein we use metal-free FLPs for polymerization of acrylic monomers, and finally realized the controlled directional polymerization.This thesis mainly works as follows:1. Using B?C₆F₅?₃ as catalyst and ammonia borane as hydrogen source, we successfully achieve metal-free catalytic hydrogenation of pyridine. In terms of the substrate suitability,2,6-diaryl substituted pyridine or 2-methyl-6-aryl substituted pyridine or even other types of pyridine fit for our catalytic system. The establishment of our catalytic system is an important supplement in the field of metal-free catalytic hydrogenation of pyridine;2. We synthesis a series of different substituent binaphthyl skeleton chiral diene. The in-situ adduction of Piers borane and diene form different kind of chiral lewis acids. Then we explore the influence of polymerization by these chiral acids and try to achieve high regularity of PMMBL. Furthermore, we examine the activity of metal-free FLPs for MMA polymerization. After screening a series of lewis base, we try to explore the mechanism of polymerization.