1. 1 and 2 are readily available from geraniol and linalool, respectively, by Claisen-Johnson rearrangement with orthoacetate catalyzed by propionic acid, and subsequent hydrolysis. 1: 67% (ref 4), 2: 54% of 2 using o-nitrophenol; V. Rautenstarauch,Swiss Pat 609 029 (23.12.1975)S.A. Firmenich,C.A. vn 90,1979,pp 186.
2. We thank Dr Rautenstrauch for additional information on unpublished work (7.11.1979 and 3.6.1983).
3. Synthese von 4-Penten-4-oliden (γ-Methylen-γ-butyrolactonen) über 4-Pentensäuren