0000000000826614
AUTHOR
Carolina Von Essen
Thiourea-Catalyzed Domino Michael–Mannich [3+2] Cycloadditions: A Strategy for the Asymmetric Synthesis of 3,3′-Pyrrolidinyl-dispirooxindoles
The asymmetric synthesis of trifluoromethylated 3,3′-pyrrolidinyl-dispirooxindole derivatives with four contiguous stereogenic centers, including two vicinal spiro-stereocenters, is described. Employing a bifunctional thiourea catalyst, a domino Michael–Mannich [3+2] cycloaddition occurs readily between isatin ketimines and isatin-derived enoates with good yields and very high stereoselectivities, providing a direct entry to the title compounds of potential medical value.
Halogen bonds in 2,5-dihalopyridine-copper(II) chloride complexes
Ten coordination complexes obtained through a facile reaction between 2,5-dihalopyridines and copperIJII) chloride (CuCl2) are characterized using single crystal X-ray diffraction. Two series of dihalopyridine complexes based on 2-chloro-5-X-pyridine and 2-bromo-5-X-pyridine (X = F, Cl, Br and I) were prepared to analyze the C–X2/X5⋯Cl–Cu halogen bonds (XB). The influence of X2- and X5-substituents on the respective interactions was examined by comparing them to the X2/X3⋯Cl–Cu XBs found in mono-substituted halopyridine complexes, (n-X-pyridine)2·CuCl2 (n = 2, 3 and X = Cl, Br and I). Varying the X5-halogens in (2,5-dihalopyridine)2·CuCl2, the C5–X5⋯Cl–Cu XBs follow the order F5 1 and they c…
Control of N-Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole-γ-Amino Acid Derivatives.
A strategy to control the switch between a non‐cycloaddition reaction and a cycloaddition reaction of enals, using N‐heterocyclic carbene (NHC) catalyisis, has been developed. The new scalable protocol leads to γ‐amino‐acid esters bearing a tetrasubstituted stereocenter in good yields and high stereoselectivities by homo‐Mannich reactions of enals and isatin‐derived ketimines. By simply changing the N‐ketimine substituent to an ortho‐hydroxy phenyl group, the corresponding spirocyclic oxindolo‐γ‐lactams are obtained. peerReviewed
Spin Switching with Triazolate-Strapped Ferrous Porphyrins
Fe(III) porphyrins bridged with 1,2,3-triazole ligands were synthesized. Upon deprotonation, the triazolate ion coordinates to the Fe(III) ion, forming an overall neutral high-spin Fe(III) porphyrin in which the triazolate serves both as an axial ligand and as the counterion. The second axial coordination site is activated for coordination and binds p-methoxypyridine, forming a six-coordinate low-spin complex. Upon addition of a phenylazopyridine as a photodissociable ligand, the spin state of the complex can be reversibly switched with ultraviolet and visible light. The system provides the basis for the development of switchable catalase- and peroxidase-type catalysts and molecular spin sw…
N-Heterocyclic Carbene Catalyzed [3+2] Cycloaddition of Enals with Masked Cinnamates for the Asymmetric One-Pot Synthesis of Adipic Acid Derivatives.
A novel short entry to 3,4-disubstituted adipic acids has been developed by employing an asymmetric NHC-catalyzed [3+2] cycloaddition of enals with masked cinnammates in moderate to good yields and high stereoselectivities. The synthetic utility of the protocol was demonstrated by the basic conversion of the masked cyclopentanone intermediates to 3S,4S-disubstituted adipic acid precursors of pharmaceutically important gababutins.
Asymmetric synthesis of functionalized tetrahydrofluorenones via an NHC-catalyzed homoenolate Michael addition
The first example of an N-heterocyclic carbene-catalyzed asymmetric desymmetrization of enal-tethered cyclohexadienones via an intramolecular homoenolate Michael addition/esterification reaction is described. This new protocol offers a direct entry to various functionalized tetrahydrofluorenones with three contiguous stereocenters in high yields, good diastereoselectivities and excellent enantioselectivities.
Halogen bonds in 2,5-dihalopyridine-copper(II) chloride complexes
Ten coordination complexes obtained through a facile reaction between 2,5-dihalopyridines and copper(II) chloride (CuCl2) are characterized using single crystal X-ray diffraction. Two series of dihalopyridine complexes based on 2-chloro-5-X-pyridine and 2-bromo-5-X-pyridine (X = F, Cl, Br and I) were prepared to analyze the C–X2/X5⋯Cl–Cu halogen bonds (XB). The influence of X2- and X5-substituents on the respective interactions was examined by comparing them to the X2/X3⋯Cl–Cu XBs found in mono-substituted halopyridine complexes, (n-X-pyridine)2·CuCl2 (n = 2, 3 and X = Cl, Br and I). Varying the X5-halogens in (2,5-dihalopyridine)2·CuCl2, the C5–X5⋯Cl–Cu XBs follow the order F5 1 and they c…
Asymmetric Synthesis of Spirocyclic β-Lactams through Copper-Catalyzed Kinugasa/Michael Domino Reactions
The first copper-catalyzed highly chemo-, regio-, diastereo-, and enantioselective Kinugasa/Michael domino reaction for the desymmetrization of prochiral cyclohexadienones is described. In the presence of a chiral copper catalyst, alkyne-tethered cyclohexadienones couple with nitrones to generate the chiral spirocyclic lactams with excellent stereoselectivity (up to 97 % ee, >20:1 dr). The new method provides direct access to versatile highly functionalized spirocyclic β-lactams possessing four contiguous stereocenters, including one quaternary and one tetra-substituted stereocenter.
Organocatalytic Enantioselective Vinylogous Henry Reaction of 3,5-Dimethyl-4-nitroisoxazole with Trifluoromethyl Ketones
The enantioselective vinylogous Henry reaction of 3,5-dimethyl-4-nitroisoxazole with trifluoromethyl ketones employing a bifunctional squaramide organocatalyst has been developed. A series of isoxazole bearing trifluoromethyl-substituted tertiary alcohols, 2-substituted (R)-1,1,1-trifluoro-3-(3-methyl-4-nitroisoxazol-5-yl)propan-2-ols, were obtained under these mild reaction conditions in good yields and moderate to good enantioselectivities
Asymmetric Synthesis of Spirocyclic β‐Lactams via Copper‐Catalyzed Kinugasa/Michael Domino Reactions
The first copper‐catalyzed highly chemo‐, regio‐, diastereo‐, and enantioselective Kinugasa/Michael domino reaction for the desymmetrization of prochiral cyclohexadienones is described. In the presence of a chiral copper catalyst, alkyne‐tethered cyclohexadienones couple with nitrones to generate the chiral spirocyclic lactams with excellent stereoselectivity (up to 97 % ee, >20:1 dr). The new method provides direct access to versatile highly functionalized spirocyclic β‐lactams possessing four contiguous stereocenters, including one quaternary and one tetra‐substituted stereocenter. peerReviewed
Redox-Responsive Host-Guest Chemistry of a Flexible Cage with Naphthalene Walls
“Naphthocage”, a naphthalene-based organic cage, reveals very strong binding (up to 1010 M–1) to aromatic (di)cationic guests, i.e., the tetrathiafulvalene mono- and dication and methyl viologen. Intercalation of the guests between two naphthalene walls is mediated by C–H···O, C–H···π, and cation···π interactions. The guests can be switched into and out of the cage by redox processes with high binding selectivity. Oxidation of the flexible cage itself in the absence of a guest leads to a stable radical cation with the oxidized naphthalene intercalated between and stabilized by the other two. Encapsulated guest cations are released from the cavity upon cage oxidation, paving the way to futur…
Redox-Responsive Host–Guest Chemistry of a Flexible Cage with Naphthalene Walls
"Naphthocage", a naphthalene-based organic cage, reveals very strong binding (up to 1010 M-1) to aromatic (di)cationic guests, i.e., the tetrathiafulvalene mono- and dication and methyl viologen. Intercalation of the guests between two naphthalene walls is mediated by C-H···O, C-H···π, and cation···π interactions. The guests can be switched into and out of the cage by redox processes with high binding selectivity. Oxidation of the flexible cage itself in the absence of a guest leads to a stable radical cation with the oxidized naphthalene intercalated between and stabilized by the other two. Encapsulated guest cations are released from the cavity upon cage oxidation, paving the way to futur…
Halogen Bonds in 2,5-Dihalopyridine-Copper(I) Halide Coordination Polymers
Two series of 2,5-dihalopyridine-Cu(I)A (A = I, Br) complexes based on 2-X-5-iodopyridine and 2-X-5-bromopyridine (X = F, Cl, Br and I) are characterized by using single-crystal X-ray diffraction analysis to examine the nature of C2&minus
Synthesis of trans-disubstituted-2,3-dihydrobenzofurans by a formal [4 + 1] annulation between para-quinone methides and sulfonium salts
An efficient protocol for the synthesis of trans-disubstituted-2,3-dihydrobenzofurans through [4 + 1] annulation of para-quinone methides with sulfonium salts has been developed. Under very mild conditions this unprecedented reaction occurs in good to excellent yields (up to 99%), offering a straightforward access to a variety of 2,3-dihydrobenzofurans.
Halogen Bonds in Square Planar 2,5-Dihalopyridine-Copper(II) Bromide Complexes
Organocatalytic Asymmetric Synthesis of Trifluoromethylated Tetrahydrocarbazoles by a Vinylogous Michael/Aldol Formal [4+2] Annulation
N-Heterocyclic Carbene Catalyzed Asymmetric Synthesis of Dihydropyranothiazoles via Azolium Enolate Intermediates
A highly diastereo- and enantiostereoselective synthesis of bicyclic dihydropyranothiazoles combining a thiazole and δ-lactone skeleton via NHC-catalyzed [4+2] annulation of 5-alkenylthiazolones and α-chloroaldehydes has been developed. The heterocyclic products are formed via azolium enolate intermediates in good yields with high diastereo- and enantistereoselectivities.
Organocatalytic Oxa-Michael/Michael/Michael/Aldol Condensation Quadruple Domino Sequence : Asymmetric Synthesis of Tricyclic Chromanes
An efficient and highly stereoselective one-pot, four-component synthesis of functionalized tricyclic chromanes has been achieved through an organocatalyzed quadruple domino reaction. The reaction sequence involves an oxa-Michael/Michael/Michael/aldol condensation between alcohols, 2 equiv of acrolein, and nitrochromenes to generate the pharmaceutically important tricyclic chromanes bearing three contiguous stereogenic centers including a chiral tetrasubstituted carbon center in good domino yields (30–70%) and excellent diastereo- and enantioselectivities (>20:1 dr and >99% ee). peerReviewed
Halogen Bonds in Square Planar 2,5-Dihalopyridine-Copper(II) Bromide Complexes
Halogen bonding in self-complementary 1:2 metal–ligand complexes obtained from copper(II) bromide (CuBr2) and seven 2,5-dihalopyridines were analyzed using single-crystal X-ray diffraction. All presented discrete complexes form 1D polymeric chains connected with C–X···Br–Cu halogen bonds (XB). In (2-chloro-5-X-pyridine)2·CuBr2 (X = Cl, Br, and I) only the C5-halogen and in (2-bromo-5-X-pyridine)2·CuBr2 (X = Cl, Br, and I) both C2- and C5-halogens form C–X···Br–Cu halogen bonds with the X acting as the XB donor and copper-coordinated bromide as the XB acceptor. The electron-withdrawing C2-chloride in (2-chloro-5-X-pyridine)2·CuBr2 complexes has only a minor effect on the C5–X5···Br–Cu XBs, a…
Palladium Catalyzed [3+2] Cycloaddition of Vinyl Aziridine and Indane-1,3-diones: Diastereo- and Enantioselective Access to Spiro-Pyrrolidines
A mild and efficient palladium-catalyzed [3+2] cycloaddition of vinylaziridine and indane-1,3-diones has been realized. The resulting spiro-pyrrolidines were provided in excellent yields and, with the introduction of the leucine-derived phosphine ligand, moderate to good enantio- and diastereoselectivities.
CCDC 1821333: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1951454: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1951456: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1815761: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1821338: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1815759: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1951457: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1951459: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1821334: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1831622: Experimental Crystal Structure Determination
Related Article: Tao Shu, Long Zhao, Sun Li, Xiang-Yu Chen, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Angew.Chem.,Int.Ed.|57|10985|doi:10.1002/anie.201806931
CCDC 1549337: Experimental Crystal Structure Determination
Related Article: Ying Zhi, Kun Zhao, Carolina von Essen, Kari Rissanen, Dieter Enders|2017|Synlett|28|2876|doi:10.1055/s-0036-1589070
CCDC 1885475: Experimental Crystal Structure Determination
Related Article: Morten K. Peters, Sebastian Hamer, Torben Jäkel, Fynn Röhricht, Frank D. Sönnichsen, Carolina von Essen, Manu Lahtinen, Christian Naether, Kari Rissanen, Rainer Herges|2019|Inorg.Chem.|58|5265|doi:10.1021/acs.inorgchem.9b00349
CCDC 1957981: Experimental Crystal Structure Determination
Related Article: Fei Jia, Hendrik V. Schröder, Liu-Pan Yang, Carolina von Essen, Sebastian Sobottka, Biprajit Sarkar, Kari Rissanen, Wei Jiang, Christoph A. Schalley|2020|J.Am.Chem.Soc.|142|3306|doi:10.1021/jacs.9b11685
CCDC 1815760: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1821336: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1814040: Experimental Crystal Structure Determination
Related Article: Ying Zhi, Kun Zhao, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Org.Chem.Front.|5|1348|doi:10.1039/C8QO00008E
CCDC 1951458: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1884544: Experimental Crystal Structure Determination
Related Article: Morten K. Peters, Sebastian Hamer, Torben Jäkel, Fynn Röhricht, Frank D. Sönnichsen, Carolina von Essen, Manu Lahtinen, Christian Naether, Kari Rissanen, Rainer Herges|2019|Inorg.Chem.|58|5265|doi:10.1021/acs.inorgchem.9b00349
CCDC 1815757: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1951452: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1975968: Experimental Crystal Structure Determination
Related Article: Fabrizio Vetica, Stephen J. Bailey, Mukesh Kumar, Suruchi Mahajan, Carolina von Essen, Kari Rissanen, Dieter Enders|2020|Synthesis|52|2038|doi:10.1055/s-0040-1707472
CCDC 1821329: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1815756: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1816580: Experimental Crystal Structure Determination
Related Article: Mukesh Kumar, Pankaj Chauhan, Stephen J. Bailey, Ehsan Jafari, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Org.Lett.|20|1232|doi:10.1021/acs.orglett.8b00175
CCDC 1561240: Experimental Crystal Structure Determination
Related Article: Xiang-Yu Chen, Sun Li, He Sheng, Qiang Liu, Ehsan Jafari, Carolina von Essen, Kari Rissanen, Dieter Enders|2017|Chem.-Eur.J.|23|13042|doi:10.1002/chem.201703579
CCDC 1821328: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1815762: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1821327: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1815973: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1821330: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1951451: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1821335: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1821331: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1821332: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1821337: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Anssi Peuronen, Manu Lahtinen, Kari Rissanen|2018|CrystEngComm|20|1954|doi:10.1039/C8CE00209F
CCDC 1571777: Experimental Crystal Structure Determination
Related Article: Xiang-Yu Chen, Jia-Wen Xiong, Qiang Liu, Sun Li, He Sheng, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Angew.Chem.,Int.Ed.|57|300|doi:10.1002/anie.201708994
CCDC 1589299: Experimental Crystal Structure Determination
Related Article: Ehsan Jafari, Pankaj Chauhan, Mukesh Kumar, Xiang-Yu Chen, Sun Li, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Eur.J.Org.Chem.|2018|2462|doi:10.1002/ejoc.201800034
CCDC 1815758: Experimental Crystal Structure Determination
Related Article: Rakesh Puttreddy, Carolina von Essen, Kari Rissanen|2018|Eur.J.Inorg.Chem.||2393|doi:10.1002/ejic.201800144
CCDC 1951455: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305
CCDC 1844760: Experimental Crystal Structure Determination
Related Article: Tao Shu, Sun Li, Xiang-Yu Chen, Qiang Liu, Carolina von Essen, Kari Rissanen, Dieter Enders|2018|Chem.Commun.|54|7661|doi:10.1039/C8CC04145H
CCDC 1951453: Experimental Crystal Structure Determination
Related Article: Carolina von Essen, Kari Rissanen, Rakesh Puttreddy|2019|Materials|12|3305|doi:10.3390/ma12203305