Bonding and Reactivity of Germanium Enolates toward Group 14 Halides

We report the reactivity of triacylgermenolate (1) and geminal bisgermenolate (13) toward group 14 halides under mechanochemical conditions, enabling efficient access to novel acylgermanes. Reactions with halosilanes afforded a series of silyl-substituted acylgermanes (3-7), while treatment with chlorogermanes and chlorostannanes yielded Ge-Ge and Ge-Sn bonded acylgermanes (8-11). In contrast, the bisgermenolate displayed divergent reactivity, forming unprecedented four-membered Ge-Ge and Ge-Sn ring systems (15, 16). UV-Vis spectroscopy revealed pronounced bathochromic shifts and enhanced absorption for the heavier congeners, with photo-CIDNP experiments confirming α-cleavage and radical generation from the cyclic Ge-Ge compound. Overall, these findings establish triacyl- and bisgermenolates as versatile building blocks for accessing novel acylgermanes with tunable bonding motifs and photochemical properties.