Migration germyl groups

Treatment of hydrogermanium cyclopentadiene transition metal complexes with LDA can lead initially to a competition between the deprotonation of the hydrogen linked to germanium or to the cyclopentadienyl ring, but a migration of the germyl group to cyclopentadiene was actually observed (equation 192)9. 

Intramolecular migration of the germyl group from the metal... 

Antoniotti, P., Canepa, C., Tonachini, G. Theoretical studies on Wittig-type anionic migrations of alkyl, silyl and germyl groups. Trends in Organic Chemistry i095, 5, 189-201. 

The reaction of ketones with diazomethane has been thoroughly studied (55) homologous ketones or epoxides are the usual reaction products. With acylmetalloids two alternative ketones could be formed, depending on whether the silyl (or germyl) group or the (R ) group attached to the carbonyl underwent the 1,2-migration. 

In contrast to the alkyl, silyl, and germyl complexes, when E is Sn, not SnR3 but only one alkyl group on the Sn migrates to the phosphenium P to give a stannylene complex (39).23,34 Since the transition metal-phosphorus bond has considerable double-bond character (see below), the conversion from 36 to 39 corresponds to a double-bond migration from Fe=P to Fe=Sn. 

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