Synthetic Organic Reactions Involving Transition Metal Alkoxide and Thiolate Complexes as Intermediates

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Late transition metal alkoxides are regarded as important intermediates in homogeneous catalytic reactions using the complexes of these metals. The main purpose of the present study is to eludicate details of the chemical. Properties of the late transition metal alkoxide and thiolate complexes.1. Alkyl or hydride complexes of transition metals such as nickel, palladium, platinum and ruthenium react with fluorinated alcohols and hpenols to give relatively stable organotransition metal alkoxide complexes. Results of the study on reactivities of these complexes are summarized below.(1) Alkylpalladium fluoroalkoxide complexes react easily with CO to give alkylpalladium alkoxycarbonyl complexes which release the corresponding esters by geducitve elimination. This is the first example for the insertion of CO into the palladium-oxygen bond.(2) Alkoxide complexts of nickel, palladium and platinum react with the corresponding alcohol to give the alkoxide complexes associated with the alcohol through O-H・・・ O hydrogen bonding. Details of the association in the solid state and in the solution were investigated by means of X-ray crystallography as well as calorimetric measurement.(3) The above alkoxide complexes reacted with esters to cause exchange of the alkoxide groups between the alkoxide ligand and the esters. This process was developed to a process to catalyze transesterification by the palladium complexes.2. Various organopalladium thiolate complexes were prepared by reactions of dialkyl palladium complexes with allylic sulfides. The obtained complexes react with various organic halides such as methyl iodide, allyl chloride, and benzyl bromide to give slalfides by coupling of the organic halides with the thiolate ligands. Kinetic studies on the reaction with allyl chloride clarified its detailed mechanism which involves nucleophilic substitution of the organic halides by the thiolate ligands.