Aromatic Spiranes, XIV: Syntheses of 2,2'-Spirobi-(s-hydrindacene) and its precursors

Article abstract of DOI:10.1007/BF00809674

The title compound 35 was prepared by catalytic reduction of the diones 29a and 11a. 29a was synthesized by systematic anellation of fivemembered rings to the positions 5,6 and 5',6', resp., of 2,2'-spirobiindane.The preparation of 11a was achieved by Friedel-Crafts cyclisation of bis-(5-indanylmethyl)-malonic acid. s-Hydrindacene-1-one 5a was prepared as a precursor for the synthesis of 11a (see forthcoming publication) and its derivates as models for corresponding anellation and substitution reactions. - Keywords: s-Hydrindacene-1-one and derivates; Mono- and bisanellation; 2,2'-Spirobiindane; 1H-nmr spectra