Acid-induced displacement of acetaldehyde from a µ-vinyloxy-triosmium cluster

Abstract

Protonation of the µ-vinyloxy-ligand in [Os₃H(µ-OCHCH₂)(CO)₁₀] with HX (X = Cl or CF₃CO₂) leads to the compounds [Os₃H(X)(CO)₁₀] with liberation of acetaldehyde (ethanal). Several intermediates including the addition species [Os₃H(µ-OCHXCH₃)(CO)₁₀](X = Cl or CF₃CO₂) have been identified (and isolated for X = Cl). These addition compounds readily undergo β-elimination of acetaldehyde. This reaction has been exploited as a synthetic route to the known complexes [Os₃H(X)(CO)₁₀](X = Cl, Br, I, CF₃CO_2′ or OH) and the new compounds from potassium O-ethyl dithiocarbonate and NN-diethyldithiocarbamate, [Os₃H(S₂COEt)(CO)₁₀](two isomers) and [Os₃H(S₂CNEt₂)(CO)₁₀]. The complex [Os₃H(S₂CNEt₂)(CO)₁₀] undergoes ready decarbonylation to [Os₃H(S₂CNEt₂)(CO)₉].