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Pincer complex-catalyzed redox coupling of alkenes with iodonium salts via presumed palladium(IV) intermediates
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
2009 (engelsk)Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, nr 13, s. 2852-2854Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Palladium pincer complexes directly catalyze the redox coupling reactions of functionalized alkenes and iodonium salts. The catalytic process, which is suitable for mild catalytic functionalization of allylic acetates and electron-rich alkenes, probably occurs through Pd(IV) intermediates. Due to the strong metal−ligand interactions, the oxidation of phosphine and amine ligands of the pincer complexes can be avoided in the presented reactions.

sted, utgiver, år, opplag, sider
American Chemical Society , 2009. Vol. 11, nr 13, s. 2852-2854
HSV kategori
Identifikatorer
URN: urn:nbn:se:su:diva-29393DOI: 10.1021/ol9010739ISI: 000267400100035OAI: oai:DiVA.org:su-29393DiVA, id: diva2:232834
Tilgjengelig fra: 2009-08-26 Laget: 2009-08-26 Sist oppdatert: 2017-12-13bibliografisk kontrollert
Inngår i avhandling
1. Catalytic Functionalization of Allylic Substrates by Palladium Pincer Complexes
Åpne denne publikasjonen i ny fane eller vindu >>Catalytic Functionalization of Allylic Substrates by Palladium Pincer Complexes
2010 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

This thesis is based on the development of novel catalytic reactions for the synthesis and application of organometallic reagents. The main focus is directed towards organoboronate derivatives. We developed an efficient procedure for converting allylic alcohols to the corresponding allylboronates using palladium pincer complexes as catalysts. The reactions were performed under mild conditions with high selectivity, allowing further one-pot transformations. Using this approach, a variety of stereodefined homoallylic alcohols and amino acid derivatives were synthesized via trapping of the in situ generated allylboronate derivatives with an appropriate electrophile. The synthetic scope of these types of multi-component reactions is broad as many different substrate allylic alcohols may be used together with various electrophiles. Several aspects of these reactions were studied, including different reagents, catalysts and electrophiles.

Furthermore, we studied the possibility to use oxidizing reagents as an essential component in the functionalization of olefins. Two main strategies were utilized for these catalytic methods using palladium pincer complexes. The functional group was either transferred from the oxidizing reagent, or introduced via an oxidation-transmetallation route. We propose that both methods involve palladium(IV) intermediates thus expanding both the coordination sphere of palladium and the synthetic scope of pincer complex catalysis.

sted, utgiver, år, opplag, sider
Stockholm: Department of Organic Chemistry, Stockholm University, 2010. s. 65
Emneord
Catalysis, Palladium, Pincer Complex, Boron, Multicomponent Reaction
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-39065 (URN)978-91-7447-090-1 (ISBN)
Disputas
2010-06-22, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 11: In press.Tilgjengelig fra: 2010-05-24 Laget: 2010-05-06 Sist oppdatert: 2010-05-21bibliografisk kontrollert
2. Transition metal-catalyzed allylic and vinylic functionalization: Method development and mechanistic investigations
Åpne denne publikasjonen i ny fane eller vindu >>Transition metal-catalyzed allylic and vinylic functionalization: Method development and mechanistic investigations
2013 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The use of small molecule building blocks in, for example, pharmaceutical research and new material development, creates a need for new and improved organic synthesis methods. The use of transition metals as mediators and catalysts opens up new reaction pathways that have made the synthesis of completely new compounds possible as well as greatly improved the synthetic routes to known compounds.

Herein, the development of new metal-mediated and catalyzed reactions for construction of vinylic and allylic carbon-carbon and carbon-heteroatom bonds is described.  The use of iodonium salts as coupling partners in Pd-catalyzed Heck type reactions with alkenes is shown to improve the current substrate scope. Results from a mechanistic study indicate that the reaction proceeds via high oxidation state palladium intermediates.

The use of IIII reagents is also believed to facilitate a PdII/PdIV catalytic cycle in allylic silylation of alkenes using (SiMe3)2, which, to the best of our knowledge, is the first method developed for metal-catalyzed allylic C-H silylation.

The same silyl-source, (SiMe3)2, has previously been used in a Pd-catalyzed allylic substitution reaction in which allylic silanes are formed from allylic alcohols. A detailed mechanistic investigation of this reaction is described in which by-products as well as intermediates, including the resting state of the catalyst, are identified using 1H, 11B, 19F and 29Si NMR spectroscopy. Kinetic experiments are performed that give information about the turn-over limiting step and the mechanism of the analogous borylation using B2pin2 is also investigated. Insights from this study further made it possible to improve the stereoselectivity of this reaction.

Additionally, a new method for Cu-mediated trifluoromethylation of allylic halides is presented in which linear products are formed exclusively from both linear and branched allylic substrates at room temperature.  Identification of allylic fluorides as by-products during the reaction also led to the development of a similar Cu-mediated reaction for the fluorination of allylic halides.

sted, utgiver, år, opplag, sider
Stockholm: Department of Organic Chemistry, Stockholm Univeristy, 2013. s. 70
Emneord
palladium, copper, catalysis, Heck reaction, C-H functionalization, allylic substitution, silylation, borylation, trifluoromethylation, fluorination, mechanistic study, transition metal, alkene, allylic silane, allylic boronate, allylic fluoride
HSV kategori
Forskningsprogram
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-89524 (URN)978-91-7447-668-2 (ISBN)
Disputas
2013-06-14, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (engelsk)
Opponent
Veileder
Merknad

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

Tilgjengelig fra: 2013-05-16 Laget: 2013-04-29 Sist oppdatert: 2014-03-17bibliografisk kontrollert

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