synthesis of optically pure spatol (+)-1 was achieved by employing asymmetric (2+2) photocycloaddition of the optically pure butenolide 12 with cyclopentenone ethylene ketal. The two major photocycloadducts 14, 15 were separately converted into the cis,anti,cis-tricyclo-[5.3.0.0.2,6]decane 9 and then to the sulfonium 11. Coupling of 11 through ylide with optically active epoxyaldehyde 24 provided optically
通过使用光学纯的
丁烯内酯12与
环戊烯酮
乙烯缩酮的不对称(2 + 2)光环加成反应,实现了光学纯的草to(+)- 1的全合成。两大photocycloadducts 14,15分别转化为顺式,反,顺-
三环[5.3.0.0。2,6 ]
癸烷9然后向锍11。的耦合11通过内鎓盐与光学活性epoxyaldehyde 24光学纯提供1具有明确的绝对构型。