Kazuhiro Kobayashi

Synthesis of Thienobenzofuranquinone Derivatives by Photoinduced and CAN-mediated 3+2-Type Cycloaddition Reactions

Photoinduced cycloaddition between ethyl 5-hydroxy-3-methyl-4,7-dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylate (la) and alkenes is reported to give ethyl 7-methyl-4,8-dioxo-2,3,4,8-tetrahydrothieno[2,3-f]benzofuran-6-carboxylates (2). Cerium(IV) ammonium nitrate (CAN)-mediated cycloaddition of ethyl 5-hydroxy-4,7-dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylates (1) to alkenes or phenylacetylene, giving ethyl 4,8-dioxo-4,8-dihydrothieno[2,3-f]benzofuran-6-carboxylate (2 or 4) and ethyl 4,5-dioxo-4,5-dihydrothieno[3,2-g]benzofuran-7-carboxylate derivatives (3 or 5), is also reported.

Synthesis of 2-(3-Iminoisoindolin-1-ylidene)carboxylate Derivatives by Reactions of Ester Magnesium Enolates with Phthalonitrile Derivatives

Efficient preparation of the title iminoisoindolines and related derivatives can be achieved via the coupling between ester magnesium enolates and one of two nitrile moieties of phthalonitriles, followed by the attack of the resulting imino anion to the second nitrile carbon.