Homogeneous Pd(OCOCF3)2/(R)-C4-TunePhos has been successfully applied in the asymmetrichydrogenation of simple ketones activated by catalytic amount of Brønstedacid with up to 88% ee.
Oxazaborolidine catalyst generated in situ from chiral lactam alcohol 3 and p-iodophenoxyborane at room temperature was found to catalyze the enantioselective borane reduction of various prochiral ...
发现在室温下由手性内酰胺醇 3 和对碘苯氧基硼烷原位生成的氧氮杂硼烷催化剂可催化各种前手性...
S<sub>N</sub>2 Type Hydrolysis of Secondary Alkyl Halides and Sulfonates in Hydrothermal Water
Optically active secondary alkylhalides and sulfonates were treated with alkaline hydrothermal water at 250 °C in sealed vessel. The hydrolysis mostly proceeded with inversion of stereochemistry.
Orchestration of Concurrent Oxidation and Reduction Cycles for Stereoinversion and Deracemisation of <i>sec</i>-Alcohols
作者:Constance V. Voss、Christian C. Gruber、Kurt Faber、Tanja Knaus、Peter Macheroux、Wolfgang Kroutil
DOI:10.1021/ja804816a
日期:2008.10.22
without significant interference. Regeneration cycles can be run in opposing directions beside each other enabling one-pot transformation of racemic alcohols to one enantiomer via concurrent enantioselective oxidation and asymmetricreduction employing defined alcoholdehydrogenases with opposite stereo- and cofactor-preference. Thus, by careful selection of appropriate enzymes, NADH recycling can be
Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 °C in the presence of 1 × 10−3 or 1 × 10−4 molar amounts of palladium catalyst prepared in situ from [PdCl(η3-C3H5)]2 and (S)-2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together
在由 [PdCl(η3-C3H5)]2 原位制备的 1 × 10−3 或 1 × 10−4 摩尔量的钯催化剂存在下,简单末端烯烃 (RCH=CH2) 与三氯硅烷在 40 °C 的不对称氢化硅烷化(S)-2-二苯基膦基-2'-甲氧基-1,1'-联萘 ((S)-MeO-MOP) 以不寻常的区域选择性和高对映选择性进行,得到高产率的 2-(三氯甲硅烷基)烷烃少量的 1-(三氯甲硅烷基)烷烃。通过碳-硅键的氧化获得旋光醇,RCH(OH)CH3。相对于 1-甲硅烷基烷烃形成 2- 甲硅烷基烷烃的区域选择性和醇的对映体纯度如下:R = n-C4H9:89/11,94% ee (R)。R = n-C6H13:93/7 95% ee (R)。R = n-C10H21:94/6,95% ee (R)。R = PhCH2CH2:81/19,97% ee (S)。R = PhCH2CH2CH2:80/20,92%