Connective methodologies for natural product synthesis

Abstract

<p>Organic synthesis is one of the most challenging fields of chemistry while natural product synthesis is the most appealing field of organic synthesis. The purpose of this research was to develop efficient synthesis of natural products or molecules that mimic natural products with biological activities beneficial to human beings. The first chapter covered a direct synthesis approach to a potential anticoccidial compound. It was achieved by electrophilic substitution of 2,3,4-thibromobut-2-en-4-olide to 1,4-dimethoxynaphthalene as the key step. Following ceric ammonium nitrate oxidation got the desired 2-(3,4-dibromo-5-oxo-2,5-dihydrofuran-2-yl)-1,4-naphthoquinone. In the second chapter, we developed a new methodology of forming two new carbon-carbon bond using [(phenyisulfonyl)-methylene]dilithium. A number of 1,4 and, 5-dicarbonyl compounds reacted with the sulfonyl-stabilized dianion and led to the corresponding fused bicyclic compounds. This new route promises to open up an entirely new approach to the total synthesis of glycinoeclapin A. The third chapter covered the study toward the total synthesis of eleutherobin. We developed a direct synthetic approach to the skeleton of eleutherobin from a commercial available keton, 6-methyl-5-hepen-2-one. It was achieved in six steps. This pathway can enable medicinal researchers to synthesize diverse analogs of eleutherobin.</p>