A streamlined method for the enantioselective synthesis of 2-amino-4H-chromenes from readily available 2-alkyl-substitutedphenols and active methylene compounds bearing a cyano group with up to 97% ee is presented. This reaction is a cascade procedure including manganese dioxide mediated C–H oxidation for the generation of o-quinone methides and bifunctional squaramide-catalyzed Michael addition/cyclization
AbstractA facile method for the stereoselective synthesis of trans‐2,3‐dihydrobenzofurans from ortho‐quinone methides in situ generated from readily available 2‐alkyl‐substituted phenols using silver oxide‐mediated oxidation has been developed. Additionally, the 2,3‐dihydrobenzofurans can be further transformed into the aromatized 2,3‐disubstituted benzofurans in the presence of DDQ.magnified image