Face‐Selective and endo‐Selective Cycloadditions with Enantiomerically Pure Cyclopentadienes

A general synthetic route to the enantiopure bicyclic cyclopentadienes (S)‐3 and (R)‐3 of the hydrindane series, starting from the Hajos‐Wiechert ketone 4 or its enantiomer is described. Reasons for the excellent face and endo selectivity of cycloadditions and the resulting consequences for chiral recognition are discussed.