0000000001307656
AUTHOR
Kun Zhao
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.
Asymmetric synthesis of cyclopentanes bearing four contiguous stereocenters via an NHC-catalyzed Michael/Michael/esterification domino reaction.
An NHC-catalyzed Michael/Michael/esterification domino reaction via homoenolate/enolate intermediates for the asymmetric synthesis of tetrasubstituted cyclopentanes is described.
ChemInform Abstract: Asymmetric Synthesis of Cyclopentanes Bearing Four Contiguous Stereocenters via an NHC-Catalyzed Michael/Michael/Esterification Domino Reaction.
An NHC-catalyzed Michael/Michael/esterification domino reaction via homoenolate/enolate intermediates for the asymmetric synthesis of tetrasubstituted cyclopentanes bearing four contiguous stereocenters is described. A variety of α,β-unsaturated aldehydes and 2-nitroallylic acetates react well with good domino yields and high stereoselectivities.
Enantioselective Total Syntheses of (+)-Hippolachnin A, (+)-Gracilioether A, (-)-Gracilioether E, and (-)-Gracilioether F.
The Plakortin polyketides represent a structurally and biologically fascinating class of marine natural products. Herein, we report a unified strategy that enables the divergent syntheses of various Plakortin polyketides with high step-economy and overall efficiency. As proof-of-concept cases, the enantioselective total syntheses of (+)-hippolachnin A, (+)-gracilioether A, (-)-gracilioether E, and (-)-gracilioether F have been accomplished based on a series of bio-inspired, rationally designed, or serendipitously discovered transformations, which include (1) an organocatalytic asymmetric 1,4-conjugate addition to assemble the common chiral γ-butenolide intermediate enroute to all of the afo…
Asymmetric synthesis of 3,3′-pyrrolidinyl-dispirooxindoles via a one-pot organocatalytic Mannich/deprotection/aza-Michael sequence
Chemical communications 52, 2249-2252 (2016). doi:10.1039/C5CC10057G
Enantioselective Total Syntheses of (+)-Hippolachnin A, (+)-Gracilioether A, (-)-Gracilioether E and (-)-Gracilioether F
The Plakortin polyketides represent a structurally and biologically fascinating class of marine natural products. Herein, we report a unified strategy that enables the divergent syntheses of various Plakortin polyketides with high step-economy and overall efficiency. As proof-of-concept cases, the enantioselective total syntheses of (+)-hippolachnin A, (+)-gracilioether A, (−)-gracilioether E, and (−)-gracilioether F have been accomplished based on a series of bio-inspired, rationally designed, or serendipitously discovered transformations, which include (1) an organocatalytic asymmetric 1,4-conjugate addition to assemble the common chiral γ-butenolide intermediate enroute to all of the afo…
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.
Organocatalytic Domino Oxa-Michael/1,6-Addition Reactions: Asymmetric Synthesis of Chromans Bearing Oxindole Scaffolds.
An asymmetric organocatalytic domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenyl-substituted para-quinone methides and isatin-derived enoates has been developed. In the presence of 5 mol % of a bifunctional thiourea organocatalyst, this scalable domino reaction affords 4-phenyl-substituted chromans bearing spiro-connected oxindole scaffolds and three adjacent stereogenic centers in good to excellent yields (up to 98 %) and with very high stereoselectivities (up to >20:1 d.r., >99 % ee).
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 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 1440552: Experimental Crystal Structure Determination
Related Article: Kun Zhao, Ying Zhi, Xinyi Li, Rakesh Puttreddy, Kari Rissanen and Dieter Enders|2016|Chem.Commun.|52|2249|doi:10.1039/C5CC10057G
CCDC 1437686: Experimental Crystal Structure Determination
Related Article: Tao Shu, Qijian Ni, Xiaoxiao Song, Kun Zhao, Tianyu Wu, Rakesh Puttreddy, Kari Rissanen, Dieter Enders|2016|Chem.Commun.|52|2609|doi:10.1039/C5CC09581F
CCDC 1493409: Experimental Crystal Structure Determination
Related Article: Kun Zhao, Ying Zhi, Tao Shu, Arto Valkonen, Kari Rissanen, Dieter Enders|2016|Angew.Chem.,Int.Ed.|55|12104|doi:10.1002/anie.201606947
CCDC 1574958: Experimental Crystal Structure Determination
Related Article: Qingong Li, Kun Zhao, Anssi Peuronen, Kari Rissanen, Dieter Enders, Yefeng Tang|2018|J.Am.Chem.Soc.|140|1937|doi:10.1021/jacs.7b12903