Isolation, total synthesis, and relative stereochemistry of a dihydrofurocoumarin from dorstenia contrajerva
The roots of Dorstenia contrajerva afforded the dihydrofurocoumarin 1b whose identity was determined from NMR spectral data of the derived acetate 7b combined with the total syntheses of 1a and 1b, which were carried out in five steps with 19% overall yield, starting from 2,3-dihydro-2-isopropenyl-6-methoxybenzofuran (2). The relative stereochemistry of 7b was determined from a single-crystal X-ray diffraction study as (2S,1'S)-2, 3-dihydro-2-(1'-hydroxy-1'-acetyloxymethylethyl)-7H-furo[3, 2g][1]benzopyran-7-one.
Instituto de Ciencias Basicas, Universidad Veracruzana, Apartado Postal 575, Xalapa, Ver., 91000 Mexico, and Departamento de Quimica del Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional, Apartado 14-7.
R
Tovar-Miranda
R
Cortes-Garcia
NF
Santos-Sanchez
P
Joseph-Nathan