I. Host/Guest Complexes for Absolute Stereochemical Determination of Organic Molecules; II. Total Synthesis Of (-)-Salinosporamide A; III. Stereocontrolled Spiroketalizations, and Efforts Towards the Total Synthesis of Obtusin

摘要

This dissertation consists of two parts. In the first part (Chapters I and II), the development of new molecular sensors for detection of asymmetry of organic molecules is disclosed. These sensors, also referred to as "host molecules", are capable of forming stable complexes with chiral organic molecules. The designs of the hosts are such that the point chirality of organic molecules is transferred into a helical twist of the molecular receptor, leading to axial chirality which can be detected as Exciton Coupled Circular Dichroism (ECCD). The absolute configuration of a few classes of organic molecules such as chiral monoamines, cyanohydrins, sulfoxides, phosphine oxides, and mono alcohols is assigned in a microscale, rapid and unambiguous manner.;In the second part of this thesis (Chapters III and IV), the development of new organic reactions and their further application towards the synthesis of natural products is discussed. In Chapter III, the successful completion of the total synthesis of (--)- Salinosporamide A is described. During the synthesis of this molecule, new reactions are developed that enabled the completion of this synthesis. In Chapter IV, the development of a halenium initiated spiroketalization and application of this methodology towards the total synthesis of Obtusin is disclosed. The enabling role of protecting group on the nucleophilic oxygen atom stands as a unique discovery that can improve the reaction outcomes.