Non-transition Metal-Catalyzed Formylation And Methylation Of Amines Using Carbon Dioxide As C₁ Building Block Under Mild Conditions

A more rational management of resources is a prerequisite for sustainable development. However, However, when dealing with the feedstock of the chemicalindustry, the level of sustainability is still far from satisfactory. Until now, most of the chemical industry’s carbon resources are based on crude oil, natural gas and coal. In the field of biomass chemistry, using CO2 as a raw material for application offers the possibility to create a renewable carbon economy. CO2 has been attracting more and more attention in the scientific community due to its abundance, availability, non-toxic and recyclable. Currently only a handful of processesutilizing CO2 as a Cl building block have been industrializedto date, namely the Bosch-Meiser process for the productionof urea from CO2 and ammonia, the Kolbe-Schmitt synthesisof salicylic acid (from CO2 and phenol salts), and the transformationof CO2 into carbonates. However, these chemical manufactures employed onlya limited amount of CO2, far failed to take full advantage of CO2. Recently a lot of new reactions utilizing CO2 as Ci raw material were reported, wherein the formylation and methylation reactions of CO2 and amines were two kinds of important reactions, since N-methylated and N-formylatedcompounds are key chemical intermediates for the synthesisof drugs, agrochemicals, dyes and fragrances. Our study is to explore new non-transition metal catalyst to catalyze the N-formylation and N-methlyation reactions of CO2 and amines.The first chapter briefly introduces the synthesis of value-added chemicals or fuel molecules utilizing CO2 as Ci raw material;the application of N-heterocyclic carbenes (NHCs) in organic synthesis as well asthe related utilization of biomass platform molecule 5-hydroxylmethylfurfural(5-HMF).The second chapter introduces the research progress of formylation of amines using CO2 and hydrosilane. Our research found that simple alkali metal carbonates can efficiently catalyze N-formylation reaction of CO2 and amines, It can be carried out under under 1 atmosphere of CO2 at room temperature, the present methodology displays a substrate scope covering aliphatic amines, aromatic amines,benzylamine, hydrazines and N-heterocyclic compound with a fairly good tolerance of functional group including allyl, nitrile group etc.An classic "cesium effect" on the reaction was observed by comparing the catalytic activity of various alkaline metal carbonates which played an important roleon the catalytic activity of alkali metal carbonates.The third chapter describes the research progress of methylationof amines using CO2 and hydrosilane. By optimizing the reaction conditions, we found that alkali metal carbonates can also selectively catalyze the methylation reaction of CO2 and amines. Then we explored the possiblereaction pathways and found that the most possible pathway for the methylationof amines using CO2 and hydrosilane. Since N-methylation has been shown to significantlyincrease the cytotoxicity of drug molecule, wenext evaluatedthe use of alkali metal carbonates in the N-methylation of drug molecules, we found they all can obtain high yields, these experiments expanded the scope of application of this method.The fourth chapter discusses the effects of different types of N-heterocyclic carbene catalyst for CO2 hydrosilylation. Since 2009, Ying and Zhang et al. reported the first case of N-heterocyclic carbene catalyzed CO2 hydrosilylation, the CO2 hydrosilylation catalyzed by N-heterocyclic carbene has become a hot research topic.we synthesized different types of N-heterocyclic carbene catalyst precursor, and studied the effect of nucleophilicity and electrophilicityof N-heterocyclic carbene to CO2 hydrosilylation systematically.The fifth chapter describes the iron-catalyzed selective oxidation of 5-hydroxylmethylfurfuralto 2,5-diformylfuran.2,5-diformylfuran has been widely used in the synthesis of pharmaceutical intermediates, fungicides and heterocyclic ligand. This approach gave 2,5-diformylfuran with good selectivity and yields employing 02 as oxidant. Our study provides a new example forthe conversion of biomass into value-added chemicals catalyzedby cheap and earth-abundant catalysts.