Synthesis of naturally occurring 6-prenylcoumarins (1a, 2c and 3a) and their derivatives 1c, 1d, 1e, 2d and 3b–d starting from 2-prenyloxybenzaldehydes (8, 12 and 14) using tandem Claisen rearrangement and Wittig reaction is described. The coumarins 1a, 1e and 2c are converted to dihydropyranocoumarins (5a–e). The conversion of dihydroxanthyletin 5a and dihydroluvangetin 5d to the naturally occurring linear pyranocoumarins xanthyletin 6a and luvangetin 6b is also described.
以 2-异
戊氧基苯甲醛(8、12 和 14)为起点,利用串联克莱森重排和维蒂希反应合成了天然 6-异戊基
香豆素(1a、2c 和 3a)及其衍
生物 1c、1d、1e、2d 和 3b-d。
香豆素 1a、1e 和 2c 被转化成二氢
吡喃
香豆素(5a-e)。此外,还介绍了将二羟基黄皮素 5a 和二氢紫罗兰素 5d 转化为天然的线型
吡喃
香豆素黄皮素 6a 和紫罗兰素 6b。