Au(I)-Catalyzed Cyclization of Epoxyalkynes to Allylic Alcohol Containing Spiroketals and Application to the Total Synthesis of (-)-Alotaketal A.

A gold-catalyzed tandem spiroketalization of epoxyalkynes accompanied by epoxide rearrangement into the corresponding allylic alcohol was developed for the construction of functionalized spiroketals. This new synthetic methodology for unsaturated spiroketals warranted a facile total synthesis of alotaketal A from carvone via a corresponding epoxyalkyne precursor.