Organocatalytic enantioselective friedel-crafts reaction of 1-naphthols with isatins and an unexpected spontaneous dehydration process

An organocatalytic enantioselective Friedel-Crafts alkylation of 1-naphthols with isatins has been developed. The process is catalyzed by a simple cinchona alkaloid derived thiourea and gives biologically interesting, enantioenriched 3-(naphthalen-2-yl)-3-hydroxy-2-oxindoles in moderate to good yields of 42-83% and with good to high enantioselectivity of up to 94% ee. Furthermore, an unexpected intramolecular dehydration reaction proceeds spontaneously with 4-substituted 1-naphthols to offer structurally different ketone oxindoles.