Iodide-Assisted Pd Catalysis as an Attractive Alternative to Rh Catalysis for the Industrially Relevant Isoselective Hydroformylation of Simple Aliphatic Alkenes.

Keywords: hydroformylation; selectivity; palladium; transition metal; aldehydes; hydrocarbons; isobutanal EN hydroformylation selectivity palladium transition metal aldehydes hydrocarbons isobutanal 1185 1194 10 06/19/23 20230704 NES 230704 1 Introduction Hydroformylation, often referred to as the oxo process, [1] is a transition-metal-catalyzed reaction of olefines with syngas - a mixture of CO and H SB 2 sb - to produce aldehydes. The key question remained whether the iodide-dependent hydroformylation activity would be pronounced in the reactions with Pd complexes that favor the formation of iso-Pd-acyl intermediates and whether the isoselectivity would be maintained throughout the release of the isoaldehyde product. We reasoned that the regioselectivity in Pd-catalyzed hydroalkoxycarbonylation of alkenes, which occurs through Pd-acyl intermediates as the hydroformylation reactions do, can be steered between I n i - and iso-products depending on the phosphine ligand used (Scheme 12). [29] (4) Most importantly, the rate- and selectivity-determining step involves the unusual iodide-assisted binuclear reductive elimination occurring between the Pd-acyl and Pd-hydride species, which releases the aldehyde product and forms a Pd(I)-Pd(I) intermediate. [Extracted from the article]