Dihydroxyalkenes or their monoprotected alcohol derivatives are transformed to 5,5- and 5,6-spiroketals through a sequence involving an initial iodocyclization, followed by a silver triflate mediated spiroketalization step on the derived hydroxy-iodoether.
                                    二羟基烯烃或其单保护醇衍
生物通过一系列步骤转化为 5,5- 和 5,6- 螺酮,这些步骤包括最初的
碘环化,然后在衍生的羟基
碘醚上进行三酸
银介导的螺酮化步骤。