Aromatic Spiranes, XV. Syntheses of 2,2'-Spirobi-(s-hydrindacene)-1,1'-dione and of 4,4'-Disubstituted 2,2'-Spirobi-(s-hydrindacenes)

Article abstract of DOI:10.1007/BF00809214

The title compound 6a was prepared by cyclisation of the diacid 4b.The diester 4a of 4b was synthesized by alkylation of 2 with 3 and following Retro-Claisen-reaction.After catalytic reduction of 6a to 8a two identical substituents were introduced by Friedel-Crafts-reaction (28).By transformation of the acetylgroups several other derivatives (29-36) could be obtained.The unsymmetrical compounds (e.g. 21) were prepared from 20, whose precurser was the spiroketon 10a. - Keywords: s-Hydrindacen-1-one and derivatives; Cyclisation; 2,2'-Spirobiindane-1,1'-diones; 2,2'-Spirobiindane-1-ones; 2,2'-Spirobiindanes; 1H nmr spectra; Mass spectra