Application of Palladium Chemistry in Organic Synthesis Techniques: the Larock Indole Synthesis, a Literature Review

Abstract

As one of the most important biologically active and naturally occurring molecules, indole is an organic compound of great importance. For more than a century, the standard method of lab preparation of the indole family of compounds has been the Fischer indole synthesis. In 1994, Richard C. Larock and Eul Kgun Yum prepared indole and indole derivatives using a new technique involving organometallic chemistry, what has since then come to be known as the Larock indole synthesis [1]. In this literature review, we give a background to the techniques involved in the Larock indole synthesis, including similar precursor methods in palladium chemistry. We mention the motivations for this reaction method, based on earlier work done. We then give a detailed overview of Larock’s work, including the reaction mechanism, kinetic effects, and effects of substituents. We also consider limitations of the Larock indole synthesis. We then study the various applications of this synthesis technique, especially synthesis of those compounds with pharmaceutical applications. We also then consider improvement to Larock’s original work, including newer, more improved techniques that built on Larock’s work, and how these newer discoveries are more beneficial to us. We end this review paper with some future questions to pursue.