ChemInform Abstract: Mechanistic Aspects of Transition‐Metal Catalyzed Alcohol Carbonylations

Abstract

Publisher Summary This chapter focuses on the nature of the transformations at the metal center, especially with regard to oxidation state and formation of the initial alkyl-, alkoxy-, or carboalkoxy-metal bond from saturated precursors, and discusses the mechanistic aspects of transition-metal-catalyzed alcohol carbonylations. Prerequisite to any catalytic activity is the ability of the metal center to interact effectively with alcohols or alcohol-derived precursors. There are several ways in which this can occur, and most of these are observed or postulated in at least one catalytic scheme. In order to understand the specific reactivities, though, the reader should be familiar with some fundamental aspects of organo-transition-metal chemistry. Homologation reactions, which are believed to usually proceed by way of aldehyde intermediates, are also discussed in the chapter but only as they pertain to the incorporation of the CO into the metal-carbon bonds. A frequent theme in alcohol carbonylations by transition metals is the use of a halide or pseudo-halide promoters or cocatalysts. Despite major problems of corrosion associated with its use, iodide is almost always found to be most effective in this capacity. This is because the halide serves several purposes, for each of which iodide is ideally suited.