Germylation of enolisable ketones, esters, amides and nitriles

A detailed investigation of the germylation of a variety of ketones, esters , amides and nitriles with trialkylgermyltriflates in the presence of the t riethylamine and with trialkylchlorogermanes and performed lithium enolates was conducted. The stereoselectivity of the germylenolates (I) formed from acyclic ketones was found to be dependent on the structure of the ketone. A mechanism for the enolization involving initial coordination of the trial kylgermyltriflate to the triethylamine with deprotonation of the ketone is proposed to explain the results. In contrast, the germylation of the esters , amides and nitriles yielded carbon-germylated compounds (II). To explain this difference, we proposed a thermodynamic rearrangement of the germyl en ol (I) into the carbon-germylated isomer (II) in the presence of Et3NHOTf.