Reactions of coordinated molecules : III. Alkoxy substituent exchange reactions on a cyclic ligand

The extraction of an ethoxide anion from a β-diethylacetal-acyl ligand of a neutral organometallic molybdenum complex affords a cationic complex having a cyclic ligand which is described best as a metal-stabilized oxonium ion. This ligand has an unusually reactive saturated carbon atom which reacts with a variety of alcohols and with ethanethiol via an alkoxy group exchange reaction affording a differently substituted cyclic ligand. The oxidization of the metal—ligand bond in the initial complex forms 4-ethoxy-γ-butyrolactone and, therefore, it is a precursor for the preparation of a variety of 4-substituted-γ-butyrolactones. The reaction of this complex with sodium methoxide and dimethyl sulfoxide is discussed, also.