New reactions under homogeneous conditions

Catalysis;Carbonyl compounds--Synthesis;Amides

Núñez Magro, Ángel Alberto ; Cole-Hamilton, D. J. (David John) ; Cole-Hamilton, D. J. (David John)

University:University of St Andrews

Department:Chemistry (School of)

关键词: Catalysis;    Carbonyl compounds--Synthesis;    Amides;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/482/AngelNunezMagroPhDThesis.pdf?sequence=6&isAllowed=y

来源: DR-NTU

【 摘 要 】

BDTBPMB has been proven to be an essential ligand in carbonylation chemistry.Its two tert-butyl groups and wide bite angle give it the ideal characteristics for this kindof chemistry, and leads to high activity and selectivity with use of its complexes. Duringthis work the group of reactions where this ligand has been proven to be active has beenextended with two new protocols for hydroxycarbonylation and aminocarbonylation. Inthe hydroxycarbonylation process, a large variety of unsaturated compounds were studied.Dioxane was found to be the ideal solvent, due to its properties in terms of coordinability,and miscibility with water. Using this solvent as the medium, a BDTBPMB complex ofpalladium was found to be highly active and selective under mild conditions.Initial attempts to address the aminocarbonylation of alkenes catalysed by thePd/BDTBPMB system did not give high activity. This problem was overcome by theaddition of an arylalcohol. Under those conditions, high selectivity and conversion wasobtained in a wide variety of amides. However, attempts to address theaminocarbonylation of alkenes with ammonia gas to generate primary amides did notresult in any conversion. The generation of these primary amides was obtained withtransamidation of N-phenylnonamides which can be prepared by aminocarbonylation.Amides have been successfully hydrogenated to amines catalysed by aRu/Triphos system. This system has been proven to be highly active in this reaction.High selectivities have been obtained in the generation of secondary amine. However,initial results of the hydrogenation of primary amides resulted in no formation of primaryamines. A careful analysis of the mechanism of the formation of various products fromthe hydrogenation of primary amides allows the selective formation of primary amines bythe ruthenium/Triphos system in the presence of ammonia. The possibility of thegeneration of primary amides in situ from acids under hydrogenation conditions, givingprimary amines was explored with high conversion and moderate selectivities.To complete this work, a system based on a palladium complex for thedecarboxylation of benzoic acids was developed. Usually, the decarboxylation reactionscatalysed by copper require high temperatures. However, palladium complexes of highlyelectron donating ligands such as BDTBPMB or P(ᵗBu)₃ were found to be highly activeunder milder conditions. This catalytic system was proven to be active in desulfonationreactions giving high conversion.