Recent Advances in the Synthesis of 4H-Benzo[d][1,3]oxathiin-4-ones and 4H-Benzo[d][1,3]dioxin-4-ones

4H-Benzo[d][1,3]oxathiin-4-ones and 4H-benzo[d][1,3]dioxin-4-ones, as important classes of sulfur- or oxygen-containing heterocyclic compounds, possess significant application potential in the fields of pharmaceutical chemistry, agriculture, and the food industry due to their distinctive structural characteristics and diverse biological activities. In recent years, efficient synthetic strategies for these compounds have witnessed remarkable progress. This review summarizes significant advancements in the construction of these heterocycles from 2012 to the present.