Synthesis, Rearrangement, and Hauser Annulation of 3-Isocyanophthalides

3-Isocyanoisobenzofuran-1(3H)-ones (phthalides) were prepared in two steps from the corresponding phthalaldehydic acids. The 3-isocyanoisobenzofuran-1(3H)-ones are readily rearranged to the corresponding 3-cyanoisobenzofuran-1(3H)-ones using triflic anhydride and 2,6-lutidine, thus enabling the synthesis of 3-cyanoisobenzofuran-1(3H)-ones without using toxic cyanide. Furthermore their annulation with Michael acceptors results in direct formation of 1,4-naphthoquinols/1,4-naphthoquinones in moderate yields.