Cycloadditions of 3-methoxyfuran (1) with several mono-activated dienophiles gave the endo adducts stereoselectively under the usual conditions in satisfactory yields; two of the adducts were transformed into potential intermediates (7a) and (7b) for the synthesis of ( f )-avenaciolide and ( ) -isoavenaciolide, respectively.CYCLOADDITIONS of furan with mono-activated dienophiles usually take place slowly (several weeks) and non-stereoselectively in low yields' and give ca. 1 : 1 mixtures of the endo and ex0 adducts, even under high pressure conditions which give satisfactory yields (ca. 55%) .2 We demonstrate here the novel reactivity of 3-methoxyfuran (1) in its stereoselective cycloadditions with dienophiles, and describe its application to the synthesis of ( f )-avenaciolides.

The synthesis of (±)-glutinosone, an antifungal norsesquiterpene from Nicotiana glutinosa infected with tobacco mosaic virus, is described. It has been completed by two processes, one being based on the Robinson annelation method and another on a modification of the Dastur procedure.

3‐Brom‐furan ergibt durch Umsetzung mit Butyllithium/Iod und anschließend mit Natriummethylat/CuO/Methanol in 55%iger Ausbeute das Methoxyfuran (I), das mit den substituierten Olefinen (II) zu den endo‐ Cycloaddukten (III) reagiert; aus Acrylnitril erhält man dabei zusätzlich 20% des exo‐Addukts.

Robinson‐Anellierung des Cyclohexanons (I) mit dem Methoiodid (II) gibt das Octahydronaphthalin (III), das über die Verbindungen (IV) und (VI) in das Epoxid (VII) übergeführt wird.

The synthesis of (±)-glutinosone, an antifungal norsesquiterpene from Nicotiana glutinosa infected with tobacco mosaic virus, is described.