Π‐Character of Chromium Germylyne Complex in the Reactions with Enone, Butadiene, and Alkynes: Formation of Germacycles through [2+4] Cycloaddition with Conjugated Molecules

Abstract

AbstractGermylyne complex Cp*(OC)2Cr≡Ge{C(SiMe3)3} (1) reacted with methyl vinyl ketone to give an η3‐allyl complex 2 with an oxagermacyclopentenyl ring. An analogous η3‐allyl complex 3 with a germacyclopentenyl ring was obtained by the reaction with butadiene, a non‐polar conjugated molecule, under photoirradiation. These reactions are accompanied by cleavage of the Cr≡Ge triple bond. On the other hand, the reactions of complex 1 with alkynes under photoirradiation resulted in clean substitution of a CO ligand of 1 to afford (η2‐alkyne)germylyne complexes, where the Cr≡Ge triple bond is intact.