Total synthesis of biologically active natural products has been used for the discovery of new medicines. In collaboration with biology and medicinal chemistry, it has led to discovery and the ensuing syntheses of biologically potent natural products, which have been translated into drug applications.

In this thesis, we explored both total synthesis and methodology of several natural products and small molecules, especially using quinone as starting materials. Chapter 2 describes an efficient synthesis of Bauhinoxepin J and polyhydroxylated xanthones via intramolecular radical cyclization, and a novel method of facile oxidation of 1,4-

hydroquinones to 1,4-benzoquinones by using N-Bromosuccinimide (NBS) was developed. Chapter 3 describes the direct synthesis of two ketone constituents, (Z)- tetradeca-8-en-11,13-diyn-2-one and (8Z,13Z)-pentadeca-8,13-dien-11-yn-2-one from Echinacea pallida. Chapter 4 describes a synthesis of Uliginosins A and B.