Bifunctional primary amine 2-aminobenzimidazole organocatalyst anchored to trans-cyclohexane-1,2-diamine in enantioselective conjugate additions of aldehydes

Bifunctional chiral primary amine 8 containing an (S,S)-trans-cyclohexane-1,2-diamine scaffold and a 2-benzimidazole unit is used as a general organocatalyst for the Michael addition of α,α-branched aldehydes to nitroalkenes and maleimides. The reactions take place, with 20 mol % of catalyst in dichloromethane at rt for nitroalkenes and with 15 mol % catalyst loading in toluene at 10 °C for maleimides, in good yields and enantioselectivities. DFT calculations demonstrate the bifunctional character of this organocatalyst activating the aldehyde by enamine formation and the Michael acceptor by double hydrogen bonding.The Spanish Ministerio de Ciencia e Innovación (MICINN) (projects CTQ2010-20387, and Consolider Ingenio 2010, CSD2007-00006), the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC), FEDER, the Generalitat Valenciana (PROMETEO 2009/039 and PROMETEOII/2014/017), the Basque Government (GV Grant IT-291-07), the FP7 Marie Curie Actions of the European Commission via the ITN ECHONET network (MCITN-2012-316379) and the Universities of Alicante and Basque Country are gratefully acknowledged for financial support. We also thank for technical and human support provided by IZO-SGI SGIker of UPV-EHU and European funding (ERDF and ESF). Financial support from Brazilian agencies CAPES-DGU (Project 200/09), CNPq, FAPERJ and UFRJ are also acknowledged. A. O. M. thanks MINECO for a FPI fellowship (BES-2014-069695)

Enantioselective electrophilic fluorination of α-aryl-tetralones using a preparation of N-fluoroammonium salts of cinchonine

The enantioselective electrophilic fluorination of α-aryl-tetralones is promoted by cinchonine/selectfluor combinations. This strategy allows a facile synthesis of the corresponding 2-fluoro-2-aryl-1-tetralones with excellent yields (up to >98%) and moderate to good enantioselectivity (up to74%).Financial support from Brazilian agencies CAPES, CNPq, FAPERJ and UFRJ is acknowledged. L. G. S. thanks Capes for the fellowship (Process CSF-PVE-S-88887.137162/2017-00). We gratefully acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) (projects CTQ2013-43446-P and CTQ2014-51912-REDC) the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (projects CTQ2016-76782-P and CTQ2016-81797-REDC), the GeneralitatValenciana (PROMETEOII/2014/017) and the University of Alicante

Asymmetric Palladium-Catalyzed Directed Intermolecular Fluoroarylation of Styrenes

A mild catalytic asymmetric direct fluoro-arylation of styrenes has been developed. The palladium-catalyzed three-component coupling of Selectfluor, a styrene and a boronic acid, provides chiral monofluorinated compounds in good yield and in high enantiomeric excess. A mechanism proceeding through a Pd­(IV)-fluoride intermediate is proposed for the transformation and synthesis of an sp³ C–F bond

Asymmetric Palladium-Catalyzed Directed Intermolecular Fluoroarylation of Styrenes

A mild catalytic asymmetric direct fluoro-arylation of styrenes has been developed. The palladium-catalyzed three-component coupling of Selectfluor, a styrene and a boronic acid, provides chiral monofluorinated compounds in good yield and in high enantiomeric excess. A mechanism proceeding through a Pd­(IV)-fluoride intermediate is proposed for the transformation and synthesis of an sp³ C–F bond