SYNTHESIS OF 2'-ALKYLSPIRO[2-X-CYCLOHEXAN-1,3'-3'H-INDOLE] (X = H X =CH3) BY AN UNEXPECTED REACTION BETWEEN AN ORGANOMAGNESIUM HALIDE AND 2'-METHYLSPIRO[2-X-CYCLOHEXAN-1,3'-3'H-INDOLE] - X-RAY STRUCTURE OF A FLUORESCENT DIMERIC COMPOUND

The reaction of 2'-methylspiro[cyclohexan-1,3'-3'H-indole] (1a) with m ethylmagnesium iodide gives 2'-ethyl-, 2'-isopropyl-, and 2'-tert-buty lspiro[cyclohexan-1,3'-3'H-indole] as the unexpected 2'-methyl inserti on products; their presence and ratio are dependent upon the reaction conditions. Influence of a methyl substituent in 2'-methylspiro[2-meth ylcyclohexan-1,3'-3'H-indole] (1b) on the reaction with methylmagnesiu m iodide has been analyzed; the 2'-ethyl (2b) and 2'-isopropyl (3b) de rivatives were obtained as the insertion products together with a lumi nescent compound that was identified by X-ray diffraction analysis as meso-(1R,2S),(1S,2R)-alpha,beta-di{(2'-(spiro[2 -methylcyclohexan-1,3' -3'H-indolyl]}ethene (10). The reaction of 1a or 1b with some active o rganomagnesium halides (allyl or benzyl) afforded the 2'-methyl-2'-alk yl-3'H-indole derivative (allyl, 5a or 5b; benzyl, 6a) as an apparent addition product. The reaction possibly occurs through a mechanism of radical intermediates.