NEW CYCLOGERMANES WITH PREFERENTIAL GEOMETRIC ISOMER, 1,2-DIMETHYLGERMACYCLOPENTANES - SYNTHESIS OF PRECURSORS

Several 2-methylgermacyclopentanes have been obtained from 1,4-dibromopentane and germanium halides by the Grignard procedure. The synthesis of 1,2-dimethylgermacyclopentane is realized in good yields in five steps from diphenyldibromogermane; the configurationally stable geometric isomers can be separated by chromatography or spinning band distillation. Attempts for stereospecific synthesis of 1,2-dimethyl-1-halogenogermacyclopentanes are also reported. The proposed configurations are supported by 1H and 13C NMR data. © 1979.