BENZOANNELATED CENTROPOLYQUINANES .8. SYNTHESIS AND REACTIONS OF 9,10,11-TRIPTINDANTRIONE AND SOME OTHER FUNCTIONALIZED TRIBENZO[3.3.3]PROPELLANES (9H,10H-4B,9A-([1,2]BENZENOMETHANO)INDENO[1,2-A]INDENES)

A new and efficient route to the tribenzo[3.3.3]propellane 1 (triptindan) and to some interesting derivatives such as 9-triptindanone (13) and 9,10,11-triptindantrione (3) has been developed. The propellane framework of 13 is accessible from 1,3-indandione in only two steps. Triketone 3, a versatile substrate with formal C3-upsilon molecular symmetry, is obtained from 13 in two further steps. First examples are presented for reactions of 3 leading to more complex benzoannelated centropolyquinanes (centropolyindans).