Pentenolide analogues of antifungal 3,5-disubstituted butenolides were prepared by oxidative cyclization of 2-(substituted aryl)hex-5-enoic acids as the key step. Given the limitations of the methodology, another approach to the title compounds based on the Pd-catalyzed carbonylative lactonization of 4-iodo-3-en-1-ols was developed, and the carbonylation conditions were optimized. While the former sequence allows only the introduction of a substituted methyl at C6, pyranones bearing a range of various C-substituents at C6 can be prepared by the latter. Somewhat surprisingly, unlike the corresponding butenolides with the same substitution pattern, the title pentenolides possess no antifungal or cytostatic activity.
抗真菌3,5-二取代丁烯酮的Pentenolide类似物通过氧化环化制备,其中2-(取代芳基)己-5-烯酸是关键步骤。鉴于该方法的局限性,基于Pd催化的4-碘-3-烯-1-醇的羰基化内酯化的另一种方法被开发出来,并优化了羰化条件。前一序列仅允许在C6引入取代甲基,而后者可以制备带有各种不同C取代基的吡喃酮。有些出乎意料的是,与具有相同取代模式的相应丁烯酮不同,标题中的Pentenolides不具有抗真菌或细胞毒活性。