A very efficient method for synthesizing spirolactones is reported. Treatment of δ,ε-unsaturated carboxylic acids with iodine and triphenylphosphine under mild conditions leads to the corresponding spiro γ-lactones in high yield and with complete stereoselectivity. Utilizing this, the first synthesis of the terpene spirolactones (â)-isoambreinolide, (+)-vitexifolin D and (+)-vitedoin B has been achieved.
报告中介绍了一种非常有效的合成
螺内酯的方法。在温和的条件下,用
碘和
三苯基膦处理δ,δ-不饱和
羧酸,可以高产率和完全立体选择性地得到相应的螺δ-内酯。利用这种方法,首次合成了
萜类螺内酯(â)-异香蒲内酯、(+)-荆芥苷 D 和(+)-荆芥苷 B。