摘要:
                                The synthesis of iptycenes 2-4, each of which is helically chiral and has a C2 symmetry axis, is described.  Key intermediates are diene 7, prepared in two steps and 44% yield from known ketone 5, and anthracene 11, prepared in four steps and 48% yield from diene 7.  A noteworthy step in the latter sequence is the aluminum chloride catalyzed, room-temperature, regio- and stereoselective cycloaddition of naphthoquinone 8 to diene 7 to give a single isomer of 9.  Anthracene 11 was converted in one step to 2 and in four steps to 3 (Scheme II).  Bicycloalkene 15, an intermediate in the latter synthesis, was converted to 4 in two steps (Scheme III).  Cycloaddition of unactivated dienophile 15 to unactivated dienes 17 and 18 proceeds in good yields.  Hydrocarbon 3 could be resolved on several chiral columns.