Organocatalytic enantioselective synthesis of phthalans via Wittig/oxa‐Michael cascade reaction

Abstract

An enantioselective synthetic method for 1‐substituted phthalans has been developed. The organocatalytic reaction between 1,3‐dihydro‐2‐benzofuran‐1‐ols and Wittig reagents using cinchona squaramide‐based organocatalyst proceeded with sequential Wittig reaction followed by an enantioselective intramolecular oxa‐Michael reaction, yielding enantioenriched phthalans with moderate to good enantioselectivities.