Conjugate Addition of 3‐Aryl Oxindoles to <i>In Situ</i> Generated <i>o</i>–Quinone Methides Without Essential Electronic or Steric Groups

Abstract Herein an efficient method for in situ generated o –quinone methides without essential electronic or steric groups at the exocyclic methylene or on six‐membered ring was established. The method relies on acetylation of salicylylols and subsequently base promoted 1,4‐elimination. The in situ generated o –quinone methides could be undergoing conjugate addition with 3‐aryl oxindoles in one‐pot reaction system, which provided 3,3‐disubstituted oxindoles bearing a quaternary stereocenter in good yields (up to 99 %).