A reinvestigation of the synthesis of trans-(±)-1,2,3,4,4a,10a-hexahydro [1,4] benzodioxino[2,3-c]pyridine

Abstract

A reinvestigation of the reaction of threo-(±)-2,3-dibromopentane-1,5-diol 5 with the disodium salt of catechol has shown that the product is (±)-1 -(2,3-dihydro[1,4]benzodioxin-2-yl)propane-1,3-diol 20 and not trans-(±)-3-(2-hydroxyethyl)-2-(hydroxymethyl)-2,3-dihydro[1,4]benzodioxin 12, as assumed previously. Consequently trans-(±)-1,2,3,4,4a,10a-hexahydro[1,4]benzodioxino[2,3-c]pyridine 3 could not have been isolated earlier, and we now report its unambiguous synthesis via the epoxide 8 as well as the crystal structure of the diol 20.