An efficient four-step synthesis of 2,4-and 2,3,4-substituted furans from -lactones via their corresponding butenolides is described.Sir: The facile elimination of selenoxides derived from «-phenylselenenyl^-lactones with almost complete formation of endocyclic ,ß-unsaturated butenolides suggested a general route to furans (eq l).1•2 We wish to report a generphy of the diffusate on silica gel with a 7:2:1 mixture of 2propanol-water-concentrated ammonia. Compound 9 was eluted between 3-aminopropanol and /3-alanine and proved to be identical in all respects with synthetic 9 obtained by hydrolysis of 10 or by treatment of 7V-(3-hydroxypropyl)-/3phthalimidopropionamide [11, from /3-alanine: (1) phthalic anhydride;(2) ClCC^Et, EtgN, 0°; (3) 3-aminopropanol], mp 166-167°, with hydrazine hydrate in EtOH (reflux) for 1 hr.14The palytoxins are. therefore substituted IV-(3-hydroxypropyl)-frans-3-amidoacrylamides (1).

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Aus den Lactonen (I) entstehen die Selenverbindungen (II), die zu den ungesättigten Lactonen (III) eliminieren und mit Bis‐isobutylaluminiumhydrid zu den Furanen (IV) umgesetzt werden können.

Die Behandlung der Dihalogenalkohole (I) mit kalter konz. Schwefelsäure liefert je nach Substituent Rdie Halogenketone (II) oder (III).