reaction of siloxyvinylindole and cyclic Z-olefin derivedfrom pyroglutamic acid gave optically active substituted hydrocarbazoles. The exo/endo selectivity of this reaction could be controlled by using an appropriate Lewis acid. Scandium triflate gave high exo-selectivity and copper triflate gave moderate endo-selectivity. Subsequent stereoselectivealkylation of the cycloadduct led to the synthesis of highly