Hydrometalation of carbon-carbon double bonds by
group 14 hydrides is inhibited bycarbonyl compounds-mainly by
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groups-as efficiently as byclassical radical trappin
g compounds, such as
galvinoxyl and hydroquinone. This phenomenon, in the case of polyfunctional C=C- and C=O-containin
g compounds, such as carvone,leads to an autoinhibition of the exocyclic alkenylic hydrometalation under normal reactionconditions, while under drastic conditions, the O-metalation of the
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group occurs.