Dinuclear Zinc-Catalyzed Asymmetric Desymmetrization of Acyclic 2-Substituted-1,3-Propanediols: A Powerful Entry into Chiral Building Blocks
作者:Barry M. Trost、Sushant Malhotra、Takashi Mino、Naomi S. Rajapaksa
DOI:10.1002/chem.200800623
日期:2008.8.28
The asymmetric acylation of meso-2-substituted-1,3-propanediols by using an amphoteric chiraldinuclear zinc catalyst is described. It is has been demonstrated that both 2-alkyl- and 2-aryl-1,3-propanediols can be desymmetrized in high yields and enantioselectivities by using the same family of ligands. Given that both antipodes of the chiral catalyst are available, both enantiomers of the desymmetrized
The present invention provides compounds which promote erythropoietin production. Compounds represented by the following general formula (1) or pharmacologically acceptable salts thereof are provided:
[wherein, R
1
represents a group —X-Q
1
, X-Q
1
-Y-Q
2
or X-Q
1
-Y-Q
2
-Z-Q
3
, X represents a single bond, —CH
2
— or the like, Q
1
represents a monocyclic or bicyclic heterocyclic group which may have substituent(s), Y represents a single bond, —CH
2
—, or the like, Q
2
represents a monocyclic or bicyclic hydrocarbon ring group which may have substituent(s) or a monocyclic or bicyclic heterocyclic group which may have substituent(s), Z represents a single bond, —CR
11
R
12
— or the like, R
11
and R
12
each independently represents a hydrogen atom, a halogen atom or the like, Q
3
represents a phenyl group which may have substituent(s), a C
3
-C
7
cycloalkyl group which may have substituent(s), a C
3
-C
7
cycloalkenyl group which may have substituent(s) or a monocyclic or bicyclic heterocyclic group which may have substituent(s), R
2
represents a C
1
-C
3
alkyl group or the like, and R
3
represents a hydrogen atom or a methyl group].
Desymmetrization of Meso 1,3- and 1,4-Diols with a Dinuclear Zinc Asymmetric Catalyst
作者:Barry M. Trost、Takashi Mino
DOI:10.1021/ja029708z
日期:2003.3.1
A dinuclear asymmetric zinc catalyst generated by mixing a 2:1 ratio of diethylzinc and 2,6-bis[5-2-diarylhydroxy methyl-1-pyrrolidinyl]-4-methylphenol has been contrasted with enzymes for the desymmetrization of some meso diols. The best ligand has a p-biphenylyl group as the aromatic substituent defining the chiral space. A series of 2-substituted propanediols were examined. The best acyl transfer agent proved to be vinyl benzoate. Diacylation normally did not occur. The phenyl substituted substrate gave 91-95% ee which compares favorably with the best ee of 92% reported for an enzymatic desymmetrization. The methyl substituted substrate gave significantly better results with the dinuclear zinc catalyst (89% yield, 82% ee) as compared to the best enzymatic esterification (70% yield, 60% ee). One case of a 1,4-diol, cis-1,2-bis(hydroxymethyl) cyclohexane, also gave much better results with the dinuclear zinc catalysts (93% yield, 91% ee) as compared to the reported enzymatic process (44% yield, 7% ee). A model to rationalize the results is presented.
Chiral Phosphoric Acid Catalyzed Highly Enantioselective Desymmetrization of 2-Substituted and 2,2-Disubstituted 1,3-Diols via Oxidative Cleavage of Benzylidene Acetals
作者:Shan-Shui Meng、Yong Liang、Kou-Sen Cao、Lufeng Zou、Xing-Bang Lin、Hui Yang、K. N. Houk、Wen-Hua Zheng
DOI:10.1021/ja507332x
日期:2014.9.3
A highly enantioselective catalytic protocol for the desymmetrization of a wide variety of 2-substituted and 2,2-disubstituted 1,3-diols is reported. This reaction proceeds through the formation of an "ortho ester" intermediate via oxidation of 1,3-diol benzylidene acetal by dimethyldioxirane (DMDO) and the subsequent proton transfer catalyzed by chiral phosphoric acid (CPA). The mechanism and origins
A wide range of prochiral 1,3-diamines were first efficiently synthesized and subsequently desymmetrized by using lipase from Pseudomonas cepacia as catalyst and diallyl carbonate as alkoxycarbonylating agent. In all cases, the amino carbamates of R-configuration were recovered. Final selective cleavage of the N-allyloxycarbonyl moiety was carried out under mild reaction conditions, which demonstrates