Synthesis of 6-methoxy-4H-1-benzopyran-7-ol, a character donating component of the fragrance of Wisteria sinensis

6-Methoxy-4H-1-benzopyran-7-ol , a major impact flavor compound of Wisteria sinensis has been synthesized from 2,4,5-trimethoxybenzaldehyde via scopoletin . The synthetic sequence comprised (i) bisdemethylation of 2,4,5-trimethoxybenzaldehyde , (ii) Wittig reaction with ethoxycarbonylmethylenetriphenylphosphorane, (iii) hydrogenation on palladium/carbon in glacial acetic acid, (iv) DIBAL-H reduction of the intermediate lactone and (v) dehydration of the lactol with anhydrous oxalic acid.