Palladium-catalyzed Allylic C-H and C-OH Functionalization. Reactions of the Obtained Allylboronic Acids
2014 (English)Licentiate thesis, monograph (Other academic)
This thesis is focused on the studies of two major transformations. The first transformation deals with the development of palladium-catalyzed selective allylic trifluoroacetoxylation reactions based on C-H functionalization, whereas the second comprises the synthesis and isolation of allylboronic acids using diboronic acid B2(OH)4 as boron source. Both reactions proceed with a very high regio- and stereoselectivity. The mechanistic studies of the allylic C-H trifluoroacetoxylation indicate that the reaction proceeds via (η3-allyl)palladium intermediate.
The reactivity of the allylboronic acids was studied with ketone and imine substrates. Unlikeother boronates (such as allyl-Bpin derivatives), allylboronic acids react with ketones and imines without any additives under neutral and mild conditions (typically at room temperature). The regio- and stereoselectivity of this reaction is remarkably high. Using functionalized allylboronic acids (prepared in the above mentioned Pd-catalyzed reactions) homoallylic alcohols and amines with adjacent tertiary and quaternary centers could be obtained with high selectivity. Interestingly, both the ketones and the imines reacted with anti-stereoselectivity. This was surprising for the imines. Our mechanistic study has shown that the acyclic aldimines undergo cis/trans isomerization prior to the allylation reaction.
Place, publisher, year, edition, pages
Stockholm: Stockholms universitets förlag, 2014. , 35 p.
IdentifiersURN: urn:nbn:se:su:diva-104083OAI: oai:DiVA.org:su-104083DiVA: diva2:720518
2014-06-18, room A501/507, Arrheniuslaboratoriet, Svante Arrheniusväg 16C, Stockholm, 11:00 (English)