Resolution of Dynamic Systems: Applications in Asymmetric Synthesis and Materials Science

This thesis is built on the concepts of constitutional dynamic chemistry and dynamic kinetic resolution, where reversible covalent reactions are used to generate dynamics and kinetically controlled reactions are employed for resolution. The thesis is divided into two parts: The first section focuses on the study of dynamic systemic resolution, a concept derived from constitutional dynamic chemistry. Three projects are addressed in this section: 1) lipase-catalyzed resolution of a double parallel dynamic system involving both hemiacetal formation and nitroaldol reaction; 2) resolution of a dynamic α-iminonitrile system through a silver-catalyzed 1,3-dipolar cycloaddition process; 3) resolution of a dynamic imine system via organogelation. Both external and internal selection pressures are applied for the resolution of complex dynamic systems. The second section explores the asymmetric synthesis of two types of heterocycles through dynamic kinetic resolution. In the first example, a series of novel N-, O-, S-containing six-membered oxathiazinanones are obtained through a lipase-mediated dynamic domino nitrone addition-cyclization pathway. In the second example, the anti-HIV nucleoside lamivudine is synthesized through a three-step surfactant-treated subtilisin Carlsberg-catalyzed dynamic kinetic resolution protocol. Its enantiomer is also accessible by changing subtilisin Carlsberg to lipases. In addition, the enzyme selectivity towards the formation of five-membered oxathiolane derivatives is investigated.QC 20140918