NEW SHORT STEP GENERAL SYNTHESIS OF ISOBENZOFURAN-1(3H)-ONES (PHTALIDES) BASED ON A SINGLE OR DOUBLE β-SCISSION OF ALKOXYL RADICALS GENERATED FROM 1-ETHYL-BENZOCYCLOBUTEN-1-OLS AND FROM 1,3-DIHYDROISOBENZOFURAN-1-OLS; SYNTHESIS OF SOME NATURAL PHTHALIDES

Article abstract of DOI:10.1016/S0040-4020(01)80977-7

New general methods are described for the synthesis of phthalides, 3-monosubstituted, and 3,3-disubstituted phthalides including naturally-occuring phthalides such as pierardine based on a regioselective single or double β-scission of the alkoxyl radicals generated by the photolysis of the hypoiodites of 1-ethyl-benzocyclobuten-1-ols or 1,2-catacondensed benzocyclobuten-1-ols or 1,3-dihydro-1,3-alkanoisobenzofuran-1-ols.The formation paths of the phthalides, which involve a regioselective single or double β-scission of the alkoxyl radicals generated from 1-alkylbenzocyclobuten-1-ols and from catacondensed benzocyclobuten-1-ols, are discussed.Key Words: Synthesis of Phthalides; Alkoxy Radicals; Mercury(II)oxide-Iodine Reagent; Photolysis; Double β-Scission