Stereoselective rhodium-catalyzed [(3+2)+2] carbocyclization reaction of trialkoxysilyl-substituted alkenylidenecyclopropanes with monosubstituted alkynes

The highly regio- and diastereoselective rhodium-catalyzed [(3+2)+2] carbocyclization reaction of trialkoxysilyl-substituted alkenylidenecyclopropanes (ACPs) with monosubstituted alkynes is reported. This work represents the first example of a metal-catalyzed higher-order carbocyclization with a vinylsilane, which facilitates the regioselective insertion of the alkyne and the selective introduction of a secondary alcohol. For example, stereospecific Tamao oxidation of the allylsilane resulting from the stereoselective cycloaddition provides the corresponding C6 hydroxyl group that is present in an array of related sesquiterpene natural products.