SYNTHESIS OF CYCLIC, CHIRAL COMPOUNDS INC LUDING GE-EL DOUBLE-BONDS (EL=N, S, (O)) AND THEIR DYNAMIC BEHAVIOR IN SOLUTION

The bis(amino)germylene 8, which can be synthesized by salt eliminatio n reactions, reacts with trimethylsilylazid, elemental sulfur, and tri methylamine N-oxide. The resulting chiral compounds 9 and 10 with Ge-N - and Ge-S-double bonds form in the solid state pairs of enantiomers, which can be proved by single crystal X-ray diffraction studies. Due t o an intramolecular donor-acceptor bond between germanium and nitrogen atoms a bicyclus is formed, in which the germanium atom, a silicon at om and the donor nitrogen atom are chiral centers. In solution an equi librium of diastereomers can be observed, resulting from an opening an d closure of the donor-acceptor bondings of two concerning nitrogen at oms to the germanium atom. Depending upon the temperature the diastere omers show different dynamics in solution. A fluctioning germanium nit rogen double bond in 10 has been observed for the first time, which or iginates from a reversible silatrope migration of a trimethylsilyl gro up. By the reaction of the bis(amino)germylene 8 with trimethylamine-N -oxide first a transient germanone 11a seems to form, which transforms to a germaimine 11b by a migration of a trimethylsilyl group. This se cond intermediate is finally, adding a further molecule of trimethylam in-N-oxide to form 12.