Synthetic Methodology 2 es special cases of acid catalyzed cyclization of 1, 5 dienes eCase 1-Butenylcyclohexhene OAC HOAC and H H x Concerted trans addition e Case 2-What if initiating cation is not proton but a carbocation? &s Stork-Eschenmoser Hypothesis H Polyunsaturated molecules with trans olefinic linkages should exhibit an inherent preference for cyclizing in a stereospecific fashion to give a polycyclic molecule with trans, anti, trans ring fusion stereochemistry &s Corollary-cis double bond will give cis-fused ring system s Stork. G. et. AL. J Am. Chem. Soc. 1955. 77. 5068-5077Synthetic Methodology 2 ? Special cases of acid catalyzed cyclization of 1,5 dienes. ?Case 1- Butenylcyclohexhene ?Case 2- What if initiating cation is not proton but a carbocation? ? Concerted trans addition. ? Stork-Eschenmoser Hypothesis Polyunsaturated molecules with trans olefinic linkages should exhibit an inherent preference for cyclizing in a stereospecific fashion to give a polycyclic molecule with trans,anti,trans ring fusion stereochemistry. ? Corollary- cis double bond will give cis-fused ring system. ? Stork. G., et. Al.; J.Am.Chem.Soc.1955, 77, 5068-5077. R R H R OAc HOAc -H R R H R R H and H H H H R R H