Enantioselective organocatalytic partial transfer hydrogenation of lactone-fused quinolines.
نویسندگان
چکیده
The first enantioselective synthesis of 4-aza-podophyllotoxin derivatives by partial transfer hydrogenation of lactone-fused quinolines was achieved using a chiral Brønsted acid catalyst. This reaction was extended to a large scope of substrates with good yields and enantioselectivities.
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 کاملEnantioselective organocatalytic transfer hydrogenation reactions using Hantzsch esters.
Within the realm of catalytic asymmetric hydrogenation, the focus continues to be on the use of chiral metal complexes in conjunction with a hydrogen source. Recently, the widespread development of organocatalysis, including the invention of iminium activation, has led to the discovery of many new enantioselective transformations. Based on this strategy, a number of bioinspired processes for th...
متن کاملOrganocatalytic transfer hydrogenation of cyclic enones.
The first enantioselective organocatalytic transfer hydrogenation of cyclic enones has been accomplished. The use of iminium catalysis has provided a new organocatalytic strategy for the enantioselective reduction of beta,beta-substituted alpha,beta-unsaturated cycloalkenones, to generate beta-stereogenic cyclic ketones. The use of imidazolidinone 4 as the asymmetric catalyst has been found to ...
متن کاملHighly enantioselective transfer hydrogenation of quinolines catalyzed by gold phosphates: achiral ligand tuning and chiral-anion control of stereoselectivity.
A little gold goes a long way: as little as 0.01 mol % of chiral gold phosphate is sufficient to afford the asymmetric transfer hydrogenation of quinolines with high stereoselectivity (up to 98 % ee). The achiral ligands on gold were found to have considerable effect on the catalytic efficiency.
متن کاملDirect enantioselective access to 4-substituted tetrahydroquinolines by catalytic asymmetric transfer hydrogenation of quinolines.
A convenient protocol for the enantioselective synthesis of 4-substituted tetrahydroquinolines has been developed. Chiral BINOL phosphoric acids promote the reduction of a wide range of 4-substituted quinolines with Hantzsch esters with good to high levels of enantioselectivity.
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ورودعنوان ژورنال:
- Organic letters
دوره 16 11 شماره
صفحات -
تاریخ انتشار 2014