Preparation, characterization, and reactions of 3-germabicyclo[3.2.1]octane and 2-germabicyclo[2.2.1]heptane derivatives

Article abstract of DOI:10.1021/om00156a016

Ring closure of the bis-Grignard derived from cis-1,3-bis(bromomethyl)cyclopentane (5) on R₂GeCl₂ (R = Ph or Me) afforded the 3-germabicyclo[3.2.1]octane system 6 or 7. Bromine cleavage of a phenyl group in 3,3-diphenyl-3-germabicyclo[3.2.1]octane (6) and subsequent nucleophilic displacement of the bromide allowed differing substitution on the germanium atom. Crystals of 6 were grown from 95% ethanol and found to crystallize in the orthorhombic space group P_na2C_A2υ (No. 33, variation) with Z = 4, a = 7.921 (2) A?, b = 31.565 (5) A?, c = 6.530 (2) A?. The refinement cycles resulted in conventional residuals of R₁ = 0.053 and R_w = 0.068 for the 1483 reflections used. The incorporation of germanium into the bicyclo[2.2.1]heptane system was achieved through a chloroplatinic acid catalyzed, intramolecular hydrogermylation reaction of di-n-butyl(3-cyclopentenylmethyl)germane (14). The physical and spectral properties of these new molecules are presented.