An enantioselective synthesis of chromanylmethanol is described. An allylic alcohol moiety is, first, introduced on the aromatic ring through a Claisen transposition. Chirality is then introduced through asymmetric Sharpless epoxidation on the allylic alcohol moiety. Cyclization into the benzopyran ring is achieved by an intramolecular coupling between the tertiary alcoholic hydroxy and the hydroquinone moiety with an excellent retention of configuration.
Stereoselective syntheses of daedalin A and quercinol, an enantiomer of daedalin A, is described. The tyrosinase inhibitory activities of daedalin A and quercinol were examined. The activity of quercinol was weaker than that of daedalin A at high concentration. (C) 2009 Elsevier Ltd. All rights reserved.