Asymmetric Synthesis Of α-aminoboronic Esters And Reaction Mechanism

Back in1860, there were reports about the boric acid compounds. With thedevelopment of the times, boric acid compounds are widely used in the synthesis. Boratecompounds as pharmaceutical and synthetic intermediates are playing an important role inthe chemical field. Applications of organic boron compounds used in the Suzuki couplingwere paid more attention.In recent years,-amino boric acid as the key part of serine enzyme antagonistic, arepaid more and more attention in drug design. The development of Amino boric acidderived drugs is also very quick. They can be used as a new anti-tumor, anti-cancer drugtargets (like Bortezomib), and it is also can be designed to be a variety of anti-cancer,anti-tumor drugs. However,as the synthesis of these compounds are often difficult, thereare few reports on the synthesis of-amino boric acid.In this thesis, it mainly introduces two aspects about the synthesis of boric acidderivatives.1. copper-NHC carbenes are used to catalyze the synthesis of-Amino boronic acid.In our method, for the first time, we developed the one pot method in the synthesis of-Amino boronic acid. The glove box is no longer a necessity. NHC-Cu-Cl catalysts cangreatly increase reactivity and shorten the reaction time. We developed different types ofsubstrates, such as ketimines and aldimines as starting materials to synthesize-aminoboronic acid. 2. In the metal free system, reactions of various aldimines, ketimines,,β-unsaturatedcarbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboronand N-heterocyclic carbenes in methanol. The reaction condition is milder and the chiralityhas also been well maintained in the synthesis of-Amino boronic acid.When using alkyneas the substrate, the β position product is the major product.