Total syntheses of three natural products, vignafuran, 2-(4-hydroxy-2-methoxyphenyl)-6-methoxybenzofuran-3-carboxylic acid methyl ester, and coumestrol from a common starting material

Vignafuran, 2-(4-hydroxy-2-methoxyphenyl)-6-methoxybenzofuran-3-carboxylic acid methyl ester, and coumestrol were synthesized from a common starting material. Reaction step involved in the synthesis of vignafuran was tetrabutylammonium fluoride-catalyzed benzo[b]furan ring formation. Ester and coumestrol were synthesize using caarbonylative ring closure methodology catalyzed by a Pd complex.