Recent Progress on Synthesis of Spirochromanone and Spirochromane Derivatives

Abstract

Nature offers plenty of opportunities to the researchers of different communities to explore heterocyclic compounds. Among the various magic heterocyclic scaffolds, chromane and chromanone are the most privileged heterocycles due to their omnipresence in most value-added chemical entities. On the other hand, spirocyclic heterocyclic moieties offer unique three-dimensional frameworks which can fit into the cavity of the proteins, including enzymes, thereby enhancing the biological properties. Considering the remarkable significance of spirocyclic systems of chromanes and chromanones, various novel strategies such as Kabbe condensation, organocatalyzed reactions, oxa/sulfa-Michael-Aldol cascade reaction, oxa-Michael/addition and 1,3-dipolar cycloaddition, among others, have emerged to access this precious heterocyclic architecture in good to excellent yields. This review summarizes the synthesis of a variety of spirochromane and spirochromanone derivatives covering the literature from 1991-2020. CONTENTS1. Introduction 2.1. Synthesis of spirochromanones 2.1.1. Kabbe condensation 2.1.2. 1,3-Dipolar cycloaddition 2.1.3. Organocatalyzed reactions 2.1.4. Miscellaneous 2.2. Synthesis of spirochromanes 2.2.1. Organocatalyzed Michael addition 2.2.2. oxa-Michael/1,6-addition reactions 2.2.3. Metal catalyzed reactions 2.2.4. Miscellaneous 3. Conclusion 4. References