Chemie der schweren carben-analogen R2M, M Si, Ge, Sn
摘要:
During thermolysis of the 7-germanorbornadiene 1 in chlorobenzene at 70-degrees-C in the presence of concentrated hydrochloric acid, besides the well-known formation of free germylene Me2Ge and its consecutive product dimethylchlorogermane 2, the polar splitting of only one Ge-C bond in 1 has been observed for the first time. It does not yield Me2Ge, but instead it rapidly forms the 1-germyl-1,4-dihydronaphthalene 3. The kinetics of this reaction at 53-degrees-C are of 2nd order, t1/2 = 20 min, k = 0.22 1 mol-1 min-1. At room temperature 3 is formed quantitatively. Also, at 70-degrees-C the slower formation of the germylene Me2Ge from 1 can be suppressed completely if HCl gas is bubbled through the reaction mixture, thus favouring the rapid formation of 3. As a by-product the 1,2-dihydronaphthalene 5 is generated.
Use of a rhodium catalyst with electron-rich and bulky chiral diphosphine ligands having C2-symmetry allowed efficient dehydrogenativesilylation of the C(sp2)–H bond of ferrocenes leading to chiral benzosiloloferrocenes. The substrate scope was expanded to hydrogermane and hydrosilanes having a ruthenocene backbone, which resulted in a new approach to benzosilole- and benzogermole-fused metallocenes