The synthesis of 2, 2-dimethyl-5-hydroxychromene (1 d) is described. The synthesis of the analogous 5, 7-dihydroxy derivatives, using similar conditions, yields the adduct 9 derived via a Bucherer type reaction. X-ray analysis of 9 demonstrated that a pyrrolidine group was in the 7-position, and that the 5-hydroxyl group was involved in a strong intramolecular hydrogen bond to the 4-keto oxygen atom.
