Oxygen—germanium bonds reactions with

The addition of mesityl nitrile oxide to stable derivatives of a germanethi-one21 and a germaneselone22 is closely related to the addition of nitrones. The reaction is regioselective again, with formation of the germanium-oxygen bond. 

While this accounts satisfactorily for the behavior of silicon compounds, and suggests again, as in the acylmetalloids, that silicon-oxygen bond formation is a powerful driving force governing the reactions of these compounds, the behavior of j8-ketones with germanium halides is not explained, and appears to require a four-center transition state. 

---