Ortho ‐Hydroxy‐Substituted Para ‐Quinone Methide: A Highly Reactive and Versatile Building Block in Organic Synthesis

ABSTRACT During the past few decades, ortho ‐hydroxy‐substituted para ‐quinone methides (HO‐ p ‐QMs) have become one of the most highly reactive, instant, and versatile synthons, which have attracted much attention in organic synthesis by many chemists and pharmacists. HO ‐p ‐QMs could be used as bifunctional substrates in domino oxa ‐Michael/1,6‐addition reactions and participated in various [4+n] annulation reactions for the assembly of various functionalized five‐ to seven‐membered oxygen‐containing heterocycles. This review summarizes the research progress of versatile synthetic applications of ortho ‐hydroxy‐substituted para ‐quinone methides and related o ‐tosylaminophenyl‐substituted p ‐quinone methides (NH‐ p ‐QMs) in recent years.