Reactions of a Tungsten–Germylyne Complex with α,β-Unsaturated Ketones: Complete Cleavage of the WGe Bond and Formation of Two Types of η³‑Germoxyallyl Tungsten Complexes

Germylyne complex Cp*­(CO)2WGe­{C­(SiMe3)3} (1) reacted with two molecules of RC­(O)­CHCH2 (R = Me, Et) to give η3-allyl complexes, in which an oxa­germa­cyclo­pentene framework was bound to an η3-allyl ligand through an oxygen atom. In the reaction with α-Me-substituted MeC­(O)­C­(Me)CH2, 1 reacted with only one molecule of the substrate to give another type of η3-allyl complex, in which a five-membered oxa­germa­cyclo­pentenyl ring was coordinated to the W center in an η3 fashion. Both reactions resulted in unprecedented complete cleavage of a WGe triple bond.