Air-stable and phosphine-free iridium catalysts for highly enantioselective hydrogenation of quinoline derivatives.
نویسندگان
چکیده
Enantioselective hydrogenation of quinoline derivatives catalyzed by phosphine-free chiral cationic Cp*Ir(OTf)(CF 3TsDPEN) complex (CF 3TsDPEN = N-(p-trifluoromethylbenzenesulfonyl)-1,2-diphenylethylene-diamine) afforded the 1,2,3,4-tetrahydroquinoline derivatives in up to 99% ee. The reaction could be carried out with a substrate-to-catalyst molar ratio as high as 1000 in undegassed methanol and with no need for inert gas protection.
منابع مشابه
A Highly Enantioselective Brønsted Acid Catalyzed Cascade Reaction: Organocatalytic Transfer Hydrogenation of Quinolines and their Application in the Synthesis of AlkaloidsThe authors acknowledge Degussa AG for generous funding
The enantioselective hydrogenation of olefins, ketones, and imines still represents an important topic in organic synthesis and catalysis. Although many highly enantioselective processes based on chiral Rh, Ru, and Ir complexes have been reported, most of these catalysts failed to give satisfactory results in the asymmetric hydrogenation of aromatic and heteroaromatic compounds. Examples of eff...
متن کاملHighly enantioselective iridium-catalyzed hydrogenation of heteroaromatic compounds, quinolines.
The highly enantioselective hydrogenation of quinoline derivatives is developed using [Ir(COD)Cl]2/(R)-MeO-Biphep/I2 system, and this methodology has been applied to the asymmetric synthesis of three naturally occurring alkaloids angustureine, galipinine, and cuspareine. This method provided an efficient access to a variety of optically active tetrahydroquinolines with up to 96% ee.
متن کاملSynthesis of a new class of conformationally rigid phosphino-oxazolines: highly enantioselective ligands for Ir-catalyzed asymmetric hydrogenation.
[reaction: see text] A new class of conformationally rigid phosphino-oxazoline ligands were synthesized from readily available enantiopure phenyl glycinol. Ir complexes with these ligands are air-stable and highly enantioselective catalysts for asymmetric hydrogenation of aryl alkenes and alpha,beta-unsaturated esters in up to 99% ee.
متن کاملApplication of phosphine-phosphite ligands in the iridium catalyzed enantioselective hydrogenation of 2-methylquinoline.
The hydrogenation of 2-methylquinoline with Ir catalysts based on chiral phosphine-phosphites has been investigated. It has been observed that the reaction is very sensitive to the nature of the ligand. Optimization of the catalyst, allowed by the highly modular structure of these phosphine-phosphites, has improved the enantioselectivity of the reaction up to 73% ee. The influence of additives ...
متن کاملAir-stable Ir-(P-Phos) complex for highly enantioselective hydrogenation of quinolines and their immobilization in poly(ethylene glycol) dimethyl ether (DMPEG).
An air-stable catalyst system Ir-(P-Phos) catalyst was found to be highly effective in the asymmetric hydrogenation of quinoline derivatives. The catalyst immobilized in DMPEG was efficiently recovered and reused eight times, retaining reactivity and enantioselectivity.
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ورودعنوان ژورنال:
- Organic letters
دوره 10 22 شماره
صفحات -
تاریخ انتشار 2008