The Chiral Compounds With Quaternary Carbon Centers Were Synthesized By Asymmetric Organic Catalysis

Pyrroloindolines and furoindolines, representing the structurally complex2-oxindole derivatives with C(3a) all-carbon chiral quaternary center, are important building blocks found in many natural and non-natural products endowed with powerful biological activity. Designing a versatile protocol to attain the comprehensive access to pyrroloindolines and furoindolines is always highly desirable. The catalytic asymmetric construction of chiral trifluoromethylated tertiary thioethers and thiols, which are important frameworks in numerous biologically active compounds is no report and represent a formidable task for the demanding hetero-quaternary stereogenic centers. This dissertation mainly focuses on two aspects as follows:1. Enantioselective Alkylation of Oxindoles to Activated Bromomethane via Bicyclic Guanidium/ZnI2Cooperative Catalysis:Comprehensive Access to Pyrroloindolines and FuroindolinesWe have developed a Guanidium/ZnI2cooperative catalytic system which provided a versatile protocol to attain the comprehensive access to pyrroloindolines and furoindolines. The study made an important breakthrough in the following aspects:1)We provide a highly facile and efficient protocol to furnish the first comprehensive synthesis of pyrroloindolines and furoindolines;2) This is the first example on the chiral guanidinium-catalyzed reaction using a Lewis acid ZnI2as co-catalyst.;3)we present the first example of bicyclic guanidinium-catalyzed asymmetric alkylation of2-oxindoles to activated bromomethanes in the presence of a weak base via the desired phase-transfer mode;4) The enantiomer of bicyclic-guanidinium which was prepared from D-tert-Leucine, and as expected, the product enantiomers were achieved with the similar excellent results2. Catalytic Asymmetric Conjugate Addition of Mercaptans to β-Substituted-p-trifluoromethyl Oxazolidinone Enoates:Access to Chiral Trifluoromethylated Tertiary Thioethers and ThiolsWe report here the first asymmetric conjugate addition of mercaptans to amide-activated β-substituted-β-trifluoromethyl olefins, to furnish the first catalytic synthesis of chiral trifluoromethylated tertiary thioethers and thiols. In the process, we demonstrated the challenge of the unprecedented amide-activated β-substituted-β-trifluoromethyl olefins for their poor reactivity, which could be overcome by introduced additional base. We also have shown the advantages of these novel olefins from achieving excellent enantioselectivity and transforming amide group to ester, acid, weinreb amide and ketone after simple modifications.