Rhodium and Palladium Catalysed Unusual Regioselective Hydroformylation and Rhodium Catalysed Reductive Carbonylation

Identificador:  TDX:3362

Handle: https://hdl.handle.net/20.500.11797/TDX3362

Autors:  Palucci, Benedetta

Resum:
The current Ph.D. Thesis deals with the development of systems for achieving unconventional regioselectivity in the hydrofomylation of terminal alkenes. Numerous scented natural substances contain an aldehyde group. As such, hydroformylation processes, where carbon monoxide and hydrogen are added onto olefins, have become invaluable methods for the fragrance companies to produce these derivatives. The regioselectivity between linear and branched product of the process is extremely substrate dependent. As a general trend, terminal alkenes, such as 1-octene, react to yield linear aldehydes while vinyl arenes, such as styrene, afford the corresponding branched products, as favoured products in Rh-catalysed hydroformylation. However, to synthetise new scented substances, accessing the opposite aldehydes would be undoubtedly beneficial. In Chapter 3 the application of newly synthetised bidentate phosphorus-nitrogen-centred ligands in the rhodium catalysed hydroformylation of 1-hexene towards the branched product, is described. In Chapter 4 is reported a novel family of phosphine-phosphite and phosphine-phosphoramidite ligands and their application in the rhodium catalysed hydroformylation of 1-octene, towards the branched aldehyde. Chapter 5 is focused on the rhodium catalysed hydroformylation of styrene with bis(dipyrrolyl-phosphoramidite) ligands, towards the production of linear product. Chapter 6 deals with the development of an unprecedent process so called “rhodium catalysed reductive carbonylation” of allylic acetate to produce the corresponding aldehyde. Furthermore, the results obtained via high pressure NMR in the study of the reactivity of the catalytic system are described. Finally, Chapter 7 presents the results obtained in the palladium catalysed hydroformylation of styrene, using formaldehyde as syngas surrogates.