The formation of η2(3e)-bonded allenyl complexes by deprotonation of four-electron donor alkyne metal complexes

Abstract

Addition of Et₃N to a solution of [Mo(η²-PhC₂CH₂Ph){P(OMe)₃}₂(η-C₅H₅)][BF₄] in (CD₃)₂CO results in a selective deuteriation of the methylene hydrogens, whereas treatment with KH-Bu^tOH-Et₂O results in H₂ loss and formation of the air- and moisture-sensitive η²(3e)-allenyl complexes [[graphic omitted]CHPh}{P(OMe)₃}_2–(η–C₅H₅)]; this reaction can be generalised and electrophiles react with these new molecules to form four-electron donor alkyne cations.