Heteroatom-Embedding Annulative -Extension (Hetero-APEX) Reactions: An Overview

Heteroatom-embedded polycyclic aromatic compounds(hetero-PACs) are a class of organic compounds contributing to a variety of research fields such as materials science, chemical biology, and soon. For applications using hetero-PACs, efficient preparation of hetero-PACs is essential. In particular, reactions transforming unfunctionalized aromatic compounds into hetero-PACs using appropriate heteroatom-containing aromatic compounds (pi-extending agents) represent the most ideal way to prepare hetero-PACs. In this review, such heteroat-om-embedding annulative pi-extension (hetero-APEX) reactions, including their reaction mechanisms and scope of substrates, are described.