Home About us Contact
|
Home About us Contact | ||
|
|
||
Iridium-Catalyzed Asymmetric Hydrogenation (Iridium-Catalyze + asymmetric_hydrogenation)
Selected AbstractsHighly Efficient and Enantioselective Iridium-Catalyzed Asymmetric Hydrogenation of N -AryliminesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Wei Li Abstract A catalytic method employing the cationic iridium-(Sc,Rp)-DuanPhos [(1R,1,R,2S,2,S)-2,2,-di- tert -butyl-2,2,,3,3, -tetrahydro-1H,1,H -1,1,-biisophosphindole] complex and BARF {tetrakis[3,5-bis(trifluoromethyl)phenyl]borate} counterion effectively catalyzes the enantioselective hydrogenation of acyclic N -arylimines with high turnover numbers (up to 10,000 TON) and excellent enantioselectivities (up to 98% ee), achieving the practical synthesis of chiral secondary amines. [source] Enantioselective Synthesis of Chiral Tetrahydroisoquinolines by Iridium-Catalyzed Asymmetric Hydrogenation of EnaminesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Pu-Cha Yan Abstract Chiral iridium complexes based on spiro phosphoramidite ligands are demonstrated to be highly efficient catalysts for the asymmetric hydrogenation of unfunctionalized enamines with an exocyclic double bond. In combination with excess iodine or potassium iodide and under hydrogen pressure, the complex Ir/(Sa,R,R)- 3a provides chiral N -alkyltetrahydroisoquinolines in high yields with up to 98% ee. The L/Ir ratio of 2:1 is crucial for obtaining a high reaction rate and enantioselectivity. A deuterium labeling experiment showed that an inverse isotope effect exists in this reaction. A possible catalytic cycle including an iridium(III) species bearing two monophosphoramidite ligands is also proposed. [source] Highly Selective Iridium-Catalyzed Asymmetric Hydrogenation of Trifluoromethyl Olefins: A New Route to Trifluoromethyl- Bearing StereocentersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Mattias Engman Abstract Fluorine-containing compounds are useful in many applications ranging from pharmaceuticals to ferroelectric crystals. We have developed a new, highly enantioselective synthetic route to trifluoromethyl-bearing stereocenters in up to 96% ee via asymmetric hydrogenation using N,P-ligated iridium catalysts. We also hydrogenated an isomeric mixture of olefins; this reaction gave the hydrogenation product highly enantioselectively (87% ee), and only the E isomer was present after the reaction had reached 56% conversion. [source] ChemInform Abstract: Iridium-Catalyzed Asymmetric Hydrogenation of N-Protected Indoles.CHEMINFORM, Issue 24 2010Alejandro Baeza Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: NeoPHOX , An Easily Accessible P,N-Ligand for Iridium-Catalyzed Asymmetric Hydrogenation: Preparation, Scope and Application in the Synthesis of Demethyl Methoxycalamenene.CHEMINFORM, Issue 10 2010Marcus G. Schrems Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Chiral Phosphino- and (Phosphinooxy)-Substituted N-Heterocyclic Carbene Ligands and Their Application in Iridium-Catalyzed Asymmetric Hydrogenation.CHEMINFORM, Issue 52 2006Steve Nanchen Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] | ||||||||||