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