Catalytic Cycloisomerization of Enyne Diesters Derived From 2‐Propargyloxyarylaldehydes

Abstract

AbstractA catalytic cycloisomerization of enyne diesters derived from 2‐propargyloxyarylaldehydes is described. The cycloisomerization, catalyzed by 10 mol% In(OTf)3, provides access to 2H‐chromenes bearing diethyl 2‐(hetero)arylidene malonates at 3‐position. This enyne metathesis‐type reaction is also useful for the synthesis of thia‐, aza‐ and quinoline analogs of the 3‐substituted 2H‐chromenes. DDQ mediated oxidative C−N bond formation and further synthetic manipulation enables the conversion of 3‐substituted 2H‐chromene into chromene‐fused molecular scaffold. Pd(0)‐catalyzed intramolecular Heck reaction on suitably substituted 2H‐chromene provides indene‐based molecular scaffold.magnified image