0000000001299332
AUTHOR
Antti J. Neuvonen
showing 20 related works from this author
Cross-Dehydrogenative Couplings between Indoles and beta-Keto Esters: Ligand-Assisted Ligand Tautomerization and Dehydrogenation via a Proton-Assiste…
2014
Cross-dehydrogenative coupling reactions between β-ketoesters and electron-rich arenes, such as indoles, proceed with high regiochemical fidelity with a range of β-ketoesters and indoles. The mechanism of the reaction between a prototypical β-ketoester, ethyl 2-oxocyclopentanonecarboxylate, and N-methylindole has been studied experimentally by monitoring the temporal course of the reaction by (1)H NMR, kinetic isotope effect studies, and control experiments. DFT calculations have been carried out using a dispersion-corrected range-separated hybrid functional (ωB97X-D) to explore the basic elementary steps of the catalytic cycle. The experimental results indicate that the reaction proceeds v…
ChemInform Abstract: Cross-Dehydrogenative Couplings Between Indoles and β-Keto Esters: Ligand-Assisted Ligand Tautomerization and Dehydrogenation vi…
2014
Cross-dehydrogenative coupling reactions between β-ketoesters and electron-rich arenes, such as indoles, proceed with high regiochemical fidelity with a range of β-ketoesters and indoles. The mechanism of the reaction between a prototypical β-ketoester, ethyl 2-oxocyclopentanonecarboxylate, and N-methylindole has been studied experimentally by monitoring the temporal course of the reaction by (1)H NMR, kinetic isotope effect studies, and control experiments. DFT calculations have been carried out using a dispersion-corrected range-separated hybrid functional (ωB97X-D) to explore the basic elementary steps of the catalytic cycle. The experimental results indicate that the reaction proceeds v…
Enantioselective Mannich reaction of β-keto esters with aromatic and aliphatic imines using a cooperatively assisted bifunctional catalyst
2014
An efficient urea-enhanced thiourea catalyst enables the enantioselective Mannich reaction between β-keto esters and N-Boc-protected imines under mild conditions and minimal catalyst loading (1–3 mol %). Aliphatic and aromatic substituents are tolerated on both reaction partners, affording the products in good enantiomeric purity. The corresponding β-amino ketones can readily be accessed via decarboxylation without loss of enantiomeric purity.
Organocatalysts Fold to Generate an Active Site Pocket for the Mannich Reaction
2017
Catalysts containing urea, thiourea and tertiary amine groups fold into a three-dimensional organized structure in solution both in the absence as well as in the presence of substrates or substrate analogues, as indicated by solution NMR and computational studies. These foldamer catalysts promote Mannich reactions with both aliphatic and aromatic imines and malonate esters. Hammett plot and secondary kinetic isotope effects provide evidence for the C-C bond forming event as the turnoverlimiting step of the Mannich reaction. Computational studies suggest two viable pathways for the C-C bond formation step, differing in the activation modes of the malonate and imine substrates. The results sh…
Reaction Mechanism of an Intramolecular Oxime Transfer Reaction: A Computational Study
2014
Density functional theory (PBE0/def2-TZVPP) calculations in conjunction with a polarizable continuum model were used to assess the mechanism of the intramolecular oxime transfer reaction that leads to the formation of isoxazolines. Different diastereomers of the intermediates as well as different oximes (formaldehyde and acetone oxime) were considered. The computed reaction profile predicts the water-addition and -expulsion steps as the highest barriers along the pathway, a conclusion that is in line with the experimental evidence obtained previously for these reactions.
Cooperative Assistance in Bifunctional Organocatalysis: Enantioselective Mannich Reactions with Aliphatic and Aromatic Imines
2012
both of which contain a thiourea moiety (Scheme 1).The catalysts are capable of deprotonating suitable nucleo-philes, such as activated carbonyl compounds. This proton-transfer reaction generates an ion pair, which is composed ofthe protonated catalyst and the anionic nucleophile interact-ing through hydrogen bonds. At least one of the NH moietiesin the protonated catalyst is involved in activating theelectrophilic reaction partner.
ChemInform Abstract: Cooperative Assistance in Bifunctional Organocatalysis: Enantioselective Mannich Reactions with Aliphatic and Aromatic Imines.
2013
both of which contain a thiourea moiety (Scheme 1).The catalysts are capable of deprotonating suitable nucleo-philes, such as activated carbonyl compounds. This proton-transfer reaction generates an ion pair, which is composed ofthe protonated catalyst and the anionic nucleophile interact-ing through hydrogen bonds. At least one of the NH moietiesin the protonated catalyst is involved in activating theelectrophilic reaction partner.
Dynamic Refolding of Ion-Pair Catalysts in Response to Different Anions.
2019
Four distinct folding patterns were identified in two foldamer-type urea-thiourea catalysts bearing a basic dimethylamino unit by a combination of X-ray crystallography, solution NMR studies, and computational studies (DFT). These patterns are characterized by different intramolecular hydrogen bonding schemes that arise largely from different thiourea conformers. The free base forms of the catalysts are characterized by folds where the intramolecular hydrogen bonds between the urea and the thiourea units remain intact. In contrast, the catalytically relevant salt forms of the catalyst, where the catalyst forms an ion pair with the substrate or substrate analogues, appear in two entirely dif…
ChemInform Abstract: Enantioselective Mannich Reaction of β-Keto Esters with Aromatic and Aliphatic Imines Using a Cooperatively Assisted Bifunctiona…
2015
The title reaction tolerates aliphatic and aromatic substituents on both reaction partners, affording products (III) as a mixture of inseparable diastereomers with low or without any diastereoselectivity.
CCDC 1901894: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1901892: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1556565: Experimental Crystal Structure Determination
2017
Related Article: Antti J. Neuvonen, Tamás Földes, Ádám Madarász, Imre Pápai, and Petri M. Pihko|2017|ACS Catalysis|7|3284|doi:10.1021/acscatal.7b00336
CCDC 1003178: Experimental Crystal Structure Determination
2014
Related Article: Mikko V. Leskinen , Ádám Madarász , Kai-Tai Yip , Aini Vuorinen , Imre Pápai , Antti J. Neuvonen , and Petri M. Pihko|2014|J.Am.Chem.Soc.|136|6453|doi:10.1021/ja501681y
CCDC 1901895: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1003179: Experimental Crystal Structure Determination
2014
Related Article: Mikko V. Leskinen , Ádám Madarász , Kai-Tai Yip , Aini Vuorinen , Imre Pápai , Antti J. Neuvonen , and Petri M. Pihko|2014|J.Am.Chem.Soc.|136|6453|doi:10.1021/ja501681y
CCDC 1901899: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1901897: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1901898: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1901893: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980
CCDC 1901896: Experimental Crystal Structure Determination
2023
Related Article: Antti J. Neuvonen, Dimitris Noutsias, Filip Topić, Kari Rissanen, Tamás Földes, Imre Pápai, Petri M. Pihko|2019|J.Org.Chem.|84|15009|doi:10.1021/acs.joc.9b01980