Study On Carbonyl Sulfide Involved Cyclization And Polymerization

Carbonyl sulfide（COS）,as the most abundant volatile sulfur compound in the atmosphere,plays a major role in the global sulfur cycle.With the increasingly rapid development of modern service industry today,CO₂ emissions have increased dramatically.Moreover,COS is proven to be a major source of acid rain because it can be oxided to SO₂ in the troposphere.From the perspective of environmental protection and energy utilization,exploring the capture and chemical utilization of COS to value-added chemicals and polymers is an important and significant research work.Sufur-containing heterocyclic compounds are representative subunits found in many synthetic drugs,biomolecules and natural products.1,3-thiazide-2,4-dione derivatives,as a kind of six-membered sufur-containing heterocyclic compounds,have been applied in medicine and organic synthetic chemistry,due to their excellent bioactivity and diverse reactivity.Up to now,some progress has been made in the synthesis of sulfur-containing six-membered heterocyclic molecules,but there are still shortcomings such as relatively single type and poor substrate functional group tolerance.On the other hand,sulfur-containing polymers refer to polymer materials containing sulfur atoms in the main chain,which have more excellent mechanical and optical properties.In recent years,the research on the application of carbonyl sulfide to sulfur-containing polymer materials has attracted the attention of many scholars and scientific researchers.Based on the research foundation of our group,this thesis will focus on design and synthesis high-efficient catalytic systems for the diverse catalytic transformations of COS,research the construction of sulfur-containing heterocyclic compounds and polymers.（1）Using Lewis Base-COS adducts as organic catalyst,the[4+2]cyclization reaction of allenamides and COS was firstly reported,and the corresponding 1,3-thiazinane-2,4-dione derivatives were obtained in good to excellent yields.The reaction shows good functional group tolerance,and has excellent chemical selectivity and stereoselectivity.A series of control experiments and isotope labeling experiments were carried out and the results show that the THPE-COS adducts behave as a lewis base activated allenamide substrates.Furthermore,1,3-thiazinane-2,4-diones can be conveniently further derivatized to generate other value-added organic compounds through simple organic reactions.（2）This thesis aims to develop efficient organocatalytic systems to synthesize highly functionalized cyclic thiocarbonates,employing cheap and easily available carbonyl sulfide and structurally diverse propargylic alcohols.Furthermore,the decarboxylative ring-opening polymerization of cyclic thiocarbonates was carried out by regulating the catalytic systems,thus forming carbon-carbon double bond functionalized polythioethers with high selectivity.This research will not only provide a theoretical basis for the utilization of carbonyl sulfide and propargyl alcohols,but also provide an alternative way for the green and efficient synthesis of sulfur-containing polymer materials.