paniculide A precursor 4 has been achieved beginning with 3-methylglutaric anhydride, and utilizing as the key step an intramolecular Diels-Alder reaction of an acetylenic oxazole to give a 2-methoxyfuran. Acid hydrolysis then provided the requisite butenolide ring characteristic of the paniculides.
从
3-甲基戊二酸酐开始,并以炔属
恶唑的分子内Diels-Alder反应为关键步骤,以得到2-甲氧基
呋喃,从而实现了抗
草酸酯A前体4的有效合成。然后,酸
水解提供了必需的
抗坏血酸丁酸酯环。