Chemical Transformation from Dihydroisocoumarin into Benzylidenephthalide by Use of Regiospecific Oxidative Lactonization Mediated by Copper Chloride(II). Syntheses of Thunberginol F and Hydramacrophyllol A and B.

Abstract

Oxidative lactonization of 2-carboxystilbene mediated by CuCl2 proceeded regiospecifically to give the five-membered lactone. By utilizing this lactonization as a key reaction, chemical transformation from dihydroisocoumarine into benzylidenephthalide was accomplished, and it was applied to structural elucidation of two new phthalide, hydramacrophyllols A and B.