Recent Advances in the Chemistry of Masked Ortho-Benzoquinones and Their Applications in Organic Synthesis

Masked ortho-benzoquinones are important intermediates in organic synthesis that exhibit a rich and fascinating chemistry. Their functionally enriched structural skeleton makes them important scaffolds in organic synthesis. They undergo a variety of interesting reactions and have found wide applications, especially in the total synthesis of many natural products. The functionalities such as alkene, diene, carbonyl, enone, dienone and ketal inherent in their structure can interfere individually or collectively in chemical transformations, making their chemistry interesting as well as challenging. Here, the work on masked ortho-benzoquinones is reviewed in terms of their reactions such as intermolecular and intramolecular Diels-Alder reactions, Michael additions, [3+2] cycloadditions, and Baylis-Hillman reactions; these reactions lead to the formation of highly functionalised heterocyclic and carbocyclic compounds that are otherwise difficult to access. This Focus Review summarises the developments in the chemistry of masked ortho-benzoquinones and covers the literature from 2005 to 2016.