Different Concepts of Catalysis in the Synthesis of Xanthenediones: A Brief Overview

Xanthenediones, also known as 1,8-dioxo-octahydroxanthenes, are synthetic compounds characterized by the presence of a pyran nucleus fused to two cyclohexen- 2-one rings. They present important biological activities as well as possible technological applications. Typically, xanthenediones are derived from the sequence reaction: Knoevenagel condensation, Michael addition and dehydration. During the cyclization step involved in the preparation of xanthenodiones, the use of a catalyst is required. Within this context, a variety of catalysts has been employed for the synthesis of xanthenediones. It is herein described an overview of catalytic methodologies that have been reported to achieve the preparation of xanthenediones.

Keywords: 1, 8-dioxo-octahydroxanthenes, Brønsted acid, Catalysts, Ionic liquid, Lewis acid, Lewis and Brønsted acid, Nanocatalyst, Organocatalyst, Pharmacological activities, Xanthenediones, Xanthenes.