在5 bar H 2下,使用RuPHOX-Ru作为手性催化剂,对各种α-取代的丙烯酸进行不对称氢化,从而以高达99%的收率和99.9%ee的产率提供相应的手性α-取代的丙酸。该反应可以以克级进行,具有相对较低的催化剂负载量(最高5000 S / C),所得产物(97%,99.3%ee)可用作构建生物活性手性分子的关键中间体。该不对称方案已成功应用于二氢青蒿酸的不对称合成,这是抗疟疾药物青蒿素工业合成所需的关键中间体。
Direct Assembly of Diverse Unsymmetrical Tertiary 9-Fluorenols via Transient Directing Group-Enabled Palladium-Catalyzed Dual C–H Bond Activation of α-Ketoesters
Piperidine derivatives and process for their production
申请人:——
公开号:US20020007068A1
公开(公告)日:2002-01-17
The present invention relates to substantially pure piperidine derivative compounds of the formulae:
1
wherein
R
1
is hydrogen or hydroxy;
R
2
is hydrogen;
or R
1
and R
2
taken together form a second bond between the carbon atoms bearing R
1
and R
2
;
R
3
is —COOH or —COOR
4
;
R
4
has 1 to 6 carbon atoms;
A, B, and D are the substituents of their respective rings each of which may be different or the same and are hydrogen, halogens, alkyl, hydroxy, alkoxy, or other substituents.
A process of preparing such piperidine derivative compounds in substantially pure form is also disclosed.
hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX–Ru as a chiral catalyst under 5 bar H2, affording the corresponding chiralα-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to
在5 bar H 2下,使用RuPHOX-Ru作为手性催化剂,对各种α-取代的丙烯酸进行不对称氢化,从而以高达99%的收率和99.9%ee的产率提供相应的手性α-取代的丙酸。该反应可以以克级进行,具有相对较低的催化剂负载量(最高5000 S / C),所得产物(97%,99.3%ee)可用作构建生物活性手性分子的关键中间体。该不对称方案已成功应用于二氢青蒿酸的不对称合成,这是抗疟疾药物青蒿素工业合成所需的关键中间体。
Direct Assembly of Diverse Unsymmetrical Tertiary 9-Fluorenols via Transient Directing Group-Enabled Palladium-Catalyzed Dual C–H Bond Activation of α-Ketoesters