2‐Hydroxypyridines as N‐ and O‐Nucleophiles in Organic Synthesis

Abstract

Abstract2‐Hydroxypyridines have emerged as versatile nucleophiles in organic synthesis. The N‐ and O‐functionalization of 2‐hydroxypyridines affords straightforward and practical methods for the construction of N‐substituted 2‐pyridones and O‐substituted 2‐hydroxypyridines, which are important structural motifs in numerous natural products, pharmaceuticals and biologically active compounds. Nonetheless, the competition between N‐ and O‐functionalization of 2‐hydroxypyridines presents an inevitable and formidable challenge. In the past few decades, chemoselective N‐ and/or O‐functionalization of 2‐hydroxypyridines has received extensive attention from the synthetic community, resulting in the development of elegant and effective strategies to address this chemoselectivity. This review provides a summary of recent advancements in the realm of transition‐metal and organo‐catalyzed, as well as visible‐light promoted chemoselective functionalization of 2‐hydroxypyridines, including N‐alkylation, N‐allylation, N‐arylation, N‐alkenylation, O‐alkylation, O‐allylation, O‐arylation, and O‐alkenylation.