Sodium hypophosphite has been used as an efficient hydrogen donor in the transfer hydrogenation of aliphatic and aromaticketones in the presence of [RuCl2(p-cymene)]2 and 2,2′-bipyridine in water. The corresponding alcohols were isolated in moderate to excellent yields (39–95 %). Good chemoselectivity was observed with ester, nitrile and halide functionalities in the ketones not being reduced. An
catalytic strategy: A highly efficient oxidation of a representative series of sec‐alcohols and diols with aq. NaOCl and 2‐azaadamantane N‐oxyl (AZADO) as organocatalyst was combined with a selective ketoreductase‐catalyzed bioreduction. The sequential one‐pot strategy, performed up to 100 mm of final substrate, yields benzyl, non‐benzyl, or hindered biaryl alcohols with very high yield and >99 % ee.
混合催化策略:用仲水高效氧化一系列代表性的仲醇和二醇。NaOCl和2-氮杂金刚烷N-氧基(AZADO)作为有机催化剂与选择性酮还原酶催化的生物还原相结合。连续一锅法在最终基材上进行了长达100 m m的反应,可制得苄基,非苄基或受阻联芳基醇,收率非常高,ee大于99%。
Dynamic Kinetic Resolution of Secondary Diols via Coupled Ruthenium and Enzyme Catalysis
作者:B. Anders Persson、Fernando F. Huerta、Jan-E. Bäckvall
DOI:10.1021/jo990447u
日期:1999.7.1
Enzymatic acylation of secondary symmetrical diols (as meso/dlmixtures) in combination with ruthenium-catalyzed isomerization of the diol led to efficient dynamic kineticresolution. In this way, a meso/dlmixture of the diol was transformed to enantiomerically pure (R,R)-diacetate, making efficient use of all the diol material. For some of the flexible substrates, substantial amounts of meso-diacetates
selective acetylation of racemic 1-[6-(1-hydroxyethyl)-pyridin-2-yl]ethanone rac-2 to yield alcohol (S)-2 and acetate (R)-3. Acetylation of a diastereomeric mixture of racemic and meso-2,6-bis(1-hydroxy-ethyl)pyridine, rac/meso-4, with the most selective Novozym 435 lipase in vinyl acetate resulted in a mixture of enantiopure diol (S,S)-4, monoacetate (R,S)-5 and diacetate (R,R)-6. Hydrolysis of the
An efficient preparation of optically pure C2-symmetric aromatic diols by the asymmetric reduction of diacylaromatic compounds with B-chlorodiisopinocampheylborane
作者:P.Veeraraghavan Ramachandran、Guang-Ming Chen、Zhi-Hui Lu、Herbert C. Brown
DOI:10.1016/0040-4039(96)00708-3
日期:1996.5
Asymmetricreduction of diacylaromaticcompounds with B-chlorodiisopinocampheylborane provides the product diols in excellent diastereomeric and enantiomeric purity.