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.

Organocatalytic Asymmetric Synthesis of 2,3′-Connected Bis-Indolinones by Mannich Reactions of N-Acetylindolin-3-ones with Isatin N-Boc Ketimines

2017

A highly diastereo- and enantioselective Mannich reaction of N-acetylindolin-3-ones with isatin N-Boc ketimines to form 2,3′-connected bis-indolinones is developed employing a low loading of a readily available bifunctional thiourea catalyst. The asymmetric synthesis connects two indolinones via a vic-diamine unit and generates two neighboring stereocenters.

Organocatalytic Enantioselective Vinylogous Henry Reaction of 3,5-Dimethyl-4-nitroisoxazole with Trifluoromethyl Ketones

2017

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

Organocatalytic Asymmetric Synthesis of Trifluoromethylated Tetrahydrocarbazoles by a Vinylogous Michael/Aldol Formal [4+2] Annulation

2018

Organocatalytic Oxa-Michael/Michael/Michael/Aldol Condensation Quadruple Domino Sequence : Asymmetric Synthesis of Tricyclic Chromanes

2018

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

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.

CCDC 1816580: Experimental Crystal Structure Determination

2018

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 1543566: Experimental Crystal Structure Determination

2018

Related Article: V. Pratap Reddy Gajulapalli, Ehsan Jafari, Dipti Sankar Kundu, Suruchi Mahajan, Anssi Peuronen, Kari Rissanen, Dieter Enders|2017|Synthesis|49|4986|doi:10.1055/s-0036-1590823

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 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 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