151766-29-9Relevant articles and documents
Asymmetric reduction of α-keto acetals with potassium 9-O-(1,2- isopropylidene-5-deoxy-D-xylofuranosyl)-9-boratabicyclo[3.3.1] nonane. Enantioselective synthesis of α-hydroxy acetals with high optical purities
Byung Tae Cho,Yu Sung Chun
, p. 1147 - 1150 (1994)
Asymmetric reduction of α-keto acetals with a chiral borohydride, potassiun 9-O-(1,2-isopropylidene-5-deoxy-α-D-xylofuranosyl)-9- boratabicyclo[3.3.1]nonane in THF at -78°C provided the corresponding α- hydroxy acetals with 87-99% ee.
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.
Catalytic enantioselective reactions. Part 16. Oxazaborolidine-catalyzed asymmetric borane reduction of α-keto acetals
Cho, Byung Tae,Chun, Yu Sung
, p. 2095 - 2100 (2007/10/03)
Asymmetric reductions of α-keto acetals using various oxazaborolidines and borane reagents as catalyst and the hydride source, respectively, were compared. The reduction catalyzed by Corey's CBS reagents with N-phenylamine-borane reagents provided α-hydro