6853-14-1Relevant articles and documents
An iron variant of the Noyori hydrogenation catalyst for the asymmetric transfer hydrogenation of ketones
Huo, Shangfei,Wang, Qingwei,Zuo, Weiwei
supporting information, p. 7959 - 7967 (2020/06/26)
We report the design of a new iron catalyst for the asymmetric transfer hydrogenation of ketones. This type of iron catalyst combines the structural characteristics of the Noyori hydrogenation catalyst (an axially chiral 2,2′-bis(phosphino)-1,1′-binaphthyl fragment and the metal-ligand bifunctional motif) and an ene(amido) group that can activate the iron center. After activation by 8 equivalents of potassiumtert-butoxide, (SA,RP,SS)-7aand (SA,RP,SS)-7bare active but nonenantioselective catalysts for the transfer hydrogenation of acetophenone and α,β-unsaturated aldehydes at room temperature in isopropanol. A maximum turnover number of 14480 was observed for (SA,RP,SS)-7ain the reduction of acetophenone. The right combination of the stereochemistry of the axially chiral 2,2′-bis(phosphino)-1,1′-binaphthyl group and the carbon-centered chiral amine-imine moiety in (SA,RP,RR)-7b′afforded an enantioselective catalyst for the preparation of chiral alcohols with moderate to good yields and a broad functional group tolerance.
PYRAZOLE CARBOXAMIDE COMPOUNDS, COMPOSITIONS AND METHODS OF USE
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Page/Page column 58, (2014/03/21)
Provided herein are compounds of formula (AA): N N H HN O N N R R 6 A (R a ) p, (AA) stereoisomers or a pharmaceutically acceptable salt thereof, wherein A, R a, p, R and R 6 are defined herein, compositions including the compounds and methods of manufacturing and using the compounds for the treatment of diseases.
Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
supporting information; scheme or table, p. 6418 - 6421 (2010/12/30)
A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.