Aromatic Spiranes, XVI: Syntheses of Mono- and Dianellated 2,2'-Spirobiindane-1,1'diones

Article abstract of DOI:10.1007/BF00810848

The spiroketones 19, 21, 24, 27, and 31 were prepared by cyclisation of the dicarboxylic acids and their acid chlorides, resp., (18, 20, 22, 23, 25, 26, 28, and 30) with polyphosphoric acid (PPA) or SnCl4.The latter compounds were synthesized by alkylation of the appropriate β-keto esters 10, 11, 12, and 13 with the "benzyl chlorides" 14, 15, 16, and subsequent retro-Claisen reaction.The spiro compounds 21a and 39 were obtained by PPA-cyclisation of the keto acids 35 and 38, which in turn were prepared by aldol-reaction of the ketones s-hydrindacen-1-on and 9a with phthalaldehydic acid to the olefinic keto acids 33 and 36 followed by catalytic hydrogenation. - Keywords: Indane-1-one; s-Hydrindacene-1-one; Tetrahydrobenzoindane-1-one; β-Keto esters; Phthalaldehydic acid; Spiro cyclisation; 2,2'-Spirobiindane-1,1'-diones; 1H-nmr spectra; Mass spectra