A diastereoselective route to the 5,7,5-tricyclic core of the guianolides is presented. This route relies on Cope rearrangement of a divinylcyclopropane prepared by alkenyl Grignard addition to a (pentadienyl)iron(+1) cation, followed by oxidative decomplexation. An additional key reaction involves oxidative rearrangement of a 3,4-epoxy-1,7-diol to generate a γ-lactone. The relative stereochemistry
提出了一种非对映选择性的途径,可以合成出该
癸醇内酯的5,7,5-
三环核。该途径依赖于通过烯基格利雅加成到(
戊二烯基)
铁(+1)阳离子上,然后氧化分解而制备的二
乙烯基环丙烷的Cope重排。另一个关键反应涉及3,4-环氧-1,7
-二醇的氧化重排以生成γ-内酯。该产物的相对立体
化学通过X射线晶体学确定。