0000000001300404
AUTHOR
Artis Kinens
Preparative-Scale Synthesis of Vedejs Chiral DMAP Catalysts
A scalable synthesis of chiral Vedejs-type DMAP catalysts is reported. The key step of the synthesis is amination of the enantiomerically pure 4-chloropyridine derivative using well-defined ZnCl2(amine)2 complexes. A series of Zn(II)–amine complexes have been synthesized to explore the scope of the ZnCl2-mediated amination of 4-halopyridines. Mechanistic studies support a Zn(II)-facilitated nucleophilic aromatic substitution as a plausible mechanism for the chlorine-to-amine exchange.
Development of a Chiral DMAP Catalyst for the Dynamic Kinetic Resolution of Azole Hemiaminals
A new catalyst for the dynamic kinetic resolution of azole hemiaminals has been developed using late-stage structural modifications of the tert-leucinol-derived chiral subunit of DMAP species.
Acylative Dynamic Kinetic Resolution of Secondary Alcohols: Tandem Catalysis by HyperBTM and Bäckvall's Ruthenium Complex.
Non-enzymatic dynamic kinetic resolution (DKR) of secondary alcohols by enantioselective acylation using an isothiourea-derived HyperBTM catalyst and racemization of slowly reacting alcohol by Backvall's ruthenium complex is reported. The DKR approach features high enantioselectivities (up to 99:1), employs easy-to-handle crystalline 4-nitrophenyl isobutyrate as the acylating reagent, and proceeds at room temperature and under an ambient atmosphere. The stereoinduction model featuring cation-π system interactions between the acylated HyperBTM catalyst and π electrons of an alcohol aryl subunit has been elaborated by DFT calculations.
Unsaturated syn- and anti-1,2-Amino Alcohols by Cyclization of Allylic Bis-trichloroacetimidates. Stereoselectivity Dependence on Substrate Configuration
Disubstituted allylic bis-imidates undergo Lewis acid catalyzed or spontaneous cyclization to oxazolines, which are precursors of unsaturated amino alcohols. Stereoselectivity of the cyclization is mainly determined by the substrate configuration. Highly selective cis-oxazoline formation is achieved starting from anti-E-bis-imidates while trans-oxazoline predominantly forms from anti-Z-bis-imidates. On the basis of DFT calculations, the stereoselectivity trends can be explained by the formation of the energetically most stable carbenium ion conformation, followed by the cyclization via most favorable bond rotations.
CCDC 1875521: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875522: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1528810: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Marcis Sejejs, Adam S. Kamlet, David W. Piotrowski, Edwin Vedejs, Edgars Suna|2017|J.Org.Chem.|82|869|doi:10.1021/acs.joc.6b02955
CCDC 1528809: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Marcis Sejejs, Adam S. Kamlet, David W. Piotrowski, Edwin Vedejs, Edgars Suna|2017|J.Org.Chem.|82|869|doi:10.1021/acs.joc.6b02955
CCDC 1875523: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875525: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687
CCDC 1875524: Experimental Crystal Structure Determination
Related Article: Artis Kinens, Simonas Balkaitis, and Edgars Suna|2018|J.Org.Chem.|83|12449|doi:10.1021/acs.joc.8b01687