A New Artificial Cyclase for Polyprenoids: Enantioselective Total Synthesis of (−)-Chromazonarol, (+)-8-<i>e</i><i>pi</i>-Puupehedione, and (−)-11‘-Deoxytaondiol Methyl Ether
pure 3-o-fluorobenzyloxy-2-hydroxy-2'-(p-methoxybemzyl)-1,1'-binaphthyl.SnCl4, which is effective for the enantioselective cyclization of 2-(polyprenyl)phenol derivatives to afford polycyclic terpenoids bearing a chroman skeleton such as (-)-chromazonarol, (+)-8-epi-puupehedione, a key synthetic intermediate of (+)-wiedendiol, and (-)-11'-deoxytaondiol methyl ether.