From α,β‐Unsaturated Aldehydes to Six‐Membered Heterocycles: Modern Synthesis of Thiazines and Oxazines

ABSTRACT Thiazine and oxazine derivatives are important heterocyclic structural motifs that confer biological activity. These compounds have extensive applications in a variety of fields, including medicine, materials science, agriculture, and organic chemistry. This review provides a comprehensive analysis of current trends in the synthesis of thiazines and oxazines, as well as their isomeric forms via α,β‐enal transformations. The structural features of the substrates, their influence on the selectivity and yields of the target products, reaction conditions, types of catalysts, transformation mechanisms, and prospects for the application of the obtained heterocycles are discussed in detail. Works published since 2015 are highlighted, and earlier sources are referenced as needed.