Metal‐Free Reaction of <i>ortho</i>‐Carbonylated Alkynyl‐Substituted Arylaldehydes with Common Amines: Selective Access to Functionalized Isoindolinone and Indenamine Derivatives

Abstract

Herein we describe a reaction of ortho-carbonylated alkynyl-substituted arylaldehydes with common primary amines that can provide functionalized isoindolinone and 3-hydroxylindenamine products in high yields. Depending on the substituent size of primary amines, two distinct reaction pathways were exploited selectively, that are, an initial aza-conjugate addition followed by hydrogen transfer to access isoindolinone framework and a unique oxa-conjugate addition followed by Petasis-Ferrier rearrangement to afford indenamine derivatives. In the presence of Et₃ N, the reaction property of small primary amines was changed, proceeding to afford 3-hydroxylindenamine derivatives efficiently. These products contain interesting substructures that exist in many natural products and bioactive molecules. The reaction features contain the use of transition-metal-free catalysts, simple operation, broad substrate scope, and product diversity.