0000000000826612
AUTHOR
Sun Li
showing 34 related works from this author
Asymmetric Synthesis of Five-Membered Spiropyrazolones via N-Heterocyclic Carbene (NHC)-Catalyzed [3+2] Annulations
2016
A new synthetic strategy for the asymmetric synthesis of five-membered spiropyrazolones via N-heterocyclic carbene-catalyzed [3+2] annulations employing enals and unsaturated pyrazolones as substrates has been developed. The new protocol allows the flexible variation of all four substituents of the pharmaceutically important spiropyrazolones in moderate to very good yields and in most cases with excellent diastereoselectivities and good to excellent enantioselectivities.
Control of N-Heterocyclic Carbene Catalyzed Reactions of Enals: Asymmetric Synthesis of Oxindole-γ-Amino Acid Derivatives.
2017
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
N-Heterocyclic Carbene Catalyzed [3+2] Cycloaddition of Enals with Masked Cinnamates for the Asymmetric One-Pot Synthesis of Adipic Acid Derivatives.
2017
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
2018
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.
Highly Enantioselective Kinetic Resolution of Michael Adducts through N-Heterocyclic Carbene Catalysis: An Efficient Asymmetric Route to Cyclohexenes
2018
Ahighly efficient strategy for the kinetic resolu-tion of Michael adductswas realized using achiral N-het-erocyclic carbene catalyst.The kinetic resolution providesanew convenientroute to single diastereomers of cyclo-hexenes and Michael adducts in good yields with highenantiomeric excesses (up to 99 % ee with aselectivityfactor of up to 458). This “two flies with one swat” con-cept allows the synthesis of these two synthetically valua-ble compound classes at the same time by asingle trans-formation. peerReviewed
N-Heterocyclic Carbene-Catalyzed Activation of α-Chloroaldehydes: Asymmetric Synthesis of 5-Cyano-Substituted Dihydropyranones
2017
An N-heterocyclic carbene (NHC)-catalyzed asymmetric [4+2] annulation of (E)-2-benzoyl-3-phenylacrylonitriles with α-chloroaldehydes has been developed. The protocol leads to 5-cyano-substituted dihydropyranones in good to excellent yields with excellent diastereo- and enantioselectivities (up to 93% yield, >20:1 d.r. and 99% ee).
Cover Feature: Highly Enantioselective Kinetic Resolution of Michael Adducts through N-Heterocyclic Carbene Catalysis: An Efficient Asymmetric Route …
2018
Asymmetric Synthesis of Spirocyclic β-Lactams through Copper-Catalyzed Kinugasa/Michael Domino Reactions
2018
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.
N‐Heterocyclic Carbene Catalyzed Asymmetric Synthesis of Pentacyclic Spirooxindoles via [3+3] Annulations of Isatin‐Derived Enals and Cyclic N‐Sulfon…
2019
Asymmetric Synthesis of Spirobenzazepinones with Atroposelectivity and Spiro-1,2-Diazepinones by NHC-Catalyzed [3+4] Annulation Reactions
2016
A strategy for the NHC-catalyzed asymmetric synthesis of spirobenzazepinones, spiro-1,2-diazepinones, and spiro-1,2-oxazepinones has been developed via [3+4]-cycloaddition reactions of isatin-derived enals (3C component) with in-situ-generated aza-o-quinone methides, azoalkenes, and nitrosoalkenes (4atom components). The [3+4] annulation strategy leads to the seven-membered target spiro heterocycles bearing an oxindole moiety in high yields and excellent enantioselectivities with a wide variety of substrates. Notably, the benzazepinone synthesis is atroposelective and an all-carbon spiro stereocenter is generated.
Asymmetric Synthesis of Spiro-oxindole-ε-lactones through N-Heterocyclic Carbene Catalysis
2018
An unprecedented N-heterocyclic carbene-catalyzed annulation of isatin-derived enals and o-hydroxyphenyl-substituted p-quinone methides as bifunctional reagents has been discovered. The new protocol involves a 1,6-addition of the homoenolate equivalent intermediates to the hydroxy donor-1,6-Michael acceptors and leads to spirocyclic oxindole-ε-lactones in high yields and very good stereoselectivities.
Organocatalytic Asymmetric Synthesis of Trifluoromethylated Tetrahydrocarbazoles by a Vinylogous Michael/Aldol Formal [4+2] Annulation
2018
N-Heterocyclic Carbene Catalyzed Asymmetric Synthesis of Dihydropyranothiazoles via Azolium Enolate Intermediates
2017
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.
Switchable Access to Different Spirocyclopentane Oxindoles by N-Heterocyclic Carbene Catalyzed Reactions of Isatin-Derived Enals and N-Sulfonyl Ketim…
2017
A novel NHC-catalyzed annulation protocol for the asymmetric synthesis of biologically important β-lactam fused spirocyclopentane oxindoles with four contiguous stereocenters, including two quaternary carbon centers, was developed. Alternatively, spirocyclopentane oxindoles containing an enaminone moiety can be achieved using the same starting materials, isatin-derived enals, and N-sulfonyl ketimines, in the presence of a slightly different NHC catalytic system. This switchable annulation strategy enables the selective assembly of both heterocyclic scaffolds with good yields and excellent enantioselectivities for a broad range of substrates.
Asymmetric, Three-Component, One-Pot Synthesis of Spiropyrazolones and 2,5-Chromenediones from Aldol Condensation/NHC-Catalyzed Annulation Reactions
2016
A novel one-pot, three-component diastereo- and enantioselective synthesis of spiropyrazolones has been developed involving the aldol condensation of an enal to generate α,β-unsaturated pyrazolones, which react with a second equivalent of enal through an N-heterocyclic carbene (NHC)-catalyzed [3+2] annulation. The desired spirocyclopentane pyrazolones are obtained in moderate to good yields and good to excellent stereoselectivities. Alternatively, starting from cyclic 1,3-diketones, 2,5-chromenediones are available through [2+4] annulation.
N‐Heterocyclic Carbene Catalyzed [4+2] Annulation of Enals via a Double Vinylogous Michael Addition: Asymmetric Synthesis of 3,5‐Diaryl Cyclohexenones
2017
A strategy for the N-heterocyclic carbene (NHC) catalyzed asymmetric synthesis of 3,5-diaryl substituted cyclohexenones has been developed via oxidative [4+2] annulation of enals and alkenylisoxazoles. It is the first example of using NHC organocatalysis in a double vinylogous Michael type reaction, a challenging but highly desirable topic. This unprecedented protocol affords good yields as well as high to excellent diastereo- and enantioselectivities.
Asymmetric Synthesis of Spirocyclic β‐Lactams via Copper‐Catalyzed Kinugasa/Michael Domino Reactions
2018
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
N-Heterocyclic Carbene Catalyzed Asymmetric Synthesis of Pentacyclic Spirooxindoles via [3+3] Annulations of Isatin-Derived Enals and Cyclic N-Sulfon…
2019
A convenient enantioselective route to new types of pentacyclic spirooxindoles via [3+3] annulation reactions of isatin-derived enals and cyclic N-sulfonyl ketimines, using N-heterocyclic carbene (NHC) catalysis has been developed. The new protocol leads to pentacyclic spirooxindoles bearing a quaternary spirostereocenter in good yields and good to high enantiomeric ratios. peerReviewed
CCDC 1831622: Experimental Crystal Structure Determination
2018
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 1818911: Experimental Crystal Structure Determination
2018
Related Article: Xiang‐Yu Chen, Sun Li, Qiang Liu, Mukesh Kumar , Anssi Peuronen, Kari Rissanen, Dieter Enders|2018|Chem.-Eur.J.|24|9735|doi:10.1002/chem.201802420
CCDC 1534938: Experimental Crystal Structure Determination
2017
Related Article: Lei Wang, Sun Li, Marcus Blümel, Rakesh Puttreddy, Anssi Peuronen, Kari Rissanen, Dieter Enders|2017|Angew.Chem.,Int.Ed.|56|8516|doi:10.1002/anie.201704210
CCDC 1453056: Experimental Crystal Structure Determination
2016
Related Article: Lei Wang, Sun Li, Marcus Blümel, Arne R. Philipps, Ai Wang, Rakesh Puttreddy, Kari Rissanen, Dieter Enders|2016|Angew.Chem.,Int.Ed.|55|11110|doi:10.1002/anie.201604819
CCDC 1831534: Experimental Crystal Structure Determination
2018
Related Article: Qiang Liu, Sun Li, Xiang-Yu Chen, Kari Rissanen, Dieter Enders|2018|Org.Lett.|20|3622|doi:10.1021/acs.orglett.8b01400
CCDC 1889531: Experimental Crystal Structure Determination
2019
Related Article: Qiang Liu, Xiang‐Yu Chen, Sun Li, Kari Rissanen, Dieter Enders|2019|Adv.Synth.Catal.|361|1991|doi:10.1002/adsc.201900065
CCDC 1442230: Experimental Crystal Structure Determination
2016
Related Article: Lei Wang, Sun Li, Pankaj Chauhan, Daniel Hack,Arne R. Philipps, Rakesh Puttreddy, Kari Rissanen, Gerhard Raabe, Dieter Enders|2016|Chem.-Eur.J.|22|5123|doi:10.1002/chem.201600515
CCDC 1561240: Experimental Crystal Structure Determination
2017
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 1555938: Experimental Crystal Structure Determination
2018
Related Article: Sun Li, Xiang-Yu Chen, Qiang Liu, Anssi Peuronen, Kari Rissanen, Dieter Enders|2017|Synthesis|49|4861|doi:10.1055/s-0036-1588509
CCDC 1413502: Experimental Crystal Structure Determination
2016
Related Article: Lei Wang, Sun Li, Marcus Blümel, Arne R. Philipps, Ai Wang, Rakesh Puttreddy, Kari Rissanen, Dieter Enders|2016|Angew.Chem.,Int.Ed.|55|11110|doi:10.1002/anie.201604819
CCDC 1446165: Experimental Crystal Structure Determination
2016
Related Article: Lei Wang, Sun Li, Pankaj Chauhan, Daniel Hack,Arne R. Philipps, Rakesh Puttreddy, Kari Rissanen, Gerhard Raabe, Dieter Enders|2016|Chem.-Eur.J.|22|5123|doi:10.1002/chem.201600515
CCDC 1527542: Experimental Crystal Structure Determination
2017
Related Article: Lei Wang, Sun Li, Marcus Blümel, Rakesh Puttreddy, Anssi Peuronen, Kari Rissanen, Dieter Enders|2017|Angew.Chem.,Int.Ed.|56|8516|doi:10.1002/anie.201704210
CCDC 1571777: Experimental Crystal Structure Determination
2017
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
2018
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 1844760: Experimental Crystal Structure Determination
2018
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 1534754: Experimental Crystal Structure Determination
2017
Related Article: Xiang-Yu Chen, Qiang Liu, Pankaj Chauhan, Sun Li, Anssi Peuronen, Kari Rissanen, Ehsan Jafari, Dieter Enders|2017|Angew.Chem.,Int.Ed.|56|6241|doi:10.1002/anie.201702881