Novel Lactonization of Ethenetricarboxylate Derivatives: Intermolecular Trapping of Alkenes.

Abstract

2005 Furan derivatives R 0060Novel Lactonization of Ethenetricarboxylate Derivatives: Intermolecular Trapping of Alkenes. -An unprecedented cyclization of the title compounds takes place by trapping of alkenes generated in situ in the presence of a Lewis acid such as SnCl4. γ-Lactone products are formed in high yields. The reaction of predeprotected carboxylic acid (VI) and various alkenes in the presence of SnCl4 yields a variety of γ-lactones in good yields. The use of a catalytic amount of SnCl 4 is also tested but affords mostly lower yields. Other Lewis acids can be used as well: in some cases the products are obtained in higher diastereoselectivity but mostly on the cost of the yield. -(YAMAZAKI*, S.; OHMITSU, K.; OHI, K.; OTSUBO, T.; MORIYAMA, K.; Org. Lett. 7 (2005) 5, 759-762; Dep. Chem., Nara Univ. Educ., Takabatake, Nara 630, Japan; Eng.) -Steudel 29-116