5‐membered lactones 3p, 3q, 16 were obtained in moderate yields. The one‐pot synthesis of kawa lactones 3a, 3r, 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)‐annularin G and (−)‐annularin H, the first asymmetric syntheses of these natural products were achieved.
双(
恶唑啉)
钯(II)催化高炔
丙醇的羰基化反应,得到无环甲氧基
丙烯酸酯2和6元内酯3a,3b,3d,3e,3f,3g,3h,3i,3j,3k。在炔
丙醇的情况下,以中等收率获得了五元内酯3p,3q,16。一锅合成川内酯3a,3r,3s并给出了二羟基巯基
噻唑A和二羟基巯基
噻唑C的正式合成。为了阐明(+)-环戊素G和(-)-环丙素H的立体
化学,实现了这些
天然产物的第一个不对称合成。