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1
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84961490050
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Asymmetric synthesis catalyzed by chiral ferrocenylphosphine-metal complexes
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For recent general reviews, see
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(1988)
Pure and Applied Chemistry
, vol.60
, pp. 7
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Hayashi1
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2
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0001230815
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Enantioselective Synthesis with Optically Active Transition-Metal Catalysts
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(1988)
Synthesis
, pp. 645
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Brunner1
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6
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0002991196
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Asymmetric Synthesis Utilizing External Chiral Ligands
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(1990)
Synthesis
, pp. 541
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Tomioka1
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16
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0001051581
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More recently, it has been reported that the degree of enantioselectivity can be greatly optimized with some heretocycles, wherein asymmetric synthesis of 3-alkoxy-γ-lactones and chromanones has been achieved with up to 91% ee and 82% ee, respectively
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(1991)
J. Am. Chem. Soc.
, vol.113
, pp. 8982
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Doyle1
Oeveren2
Westrum3
Protopopova4
Clayton5
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18
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84918759224
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The rhodium(II) complexes 1 slowly picked up water from the laboratory atmosphere. For this reason, the bis(ethyl acetate) adducts of 1 were used throughout the present experiments. It was confirmed that these adducts showed virtually the same reactivities and enantioselectivities as 1.
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19
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84918717577
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The structure of 1a was established as the bis(4-tert-butylpyridine) adduct by a single-crystal X-ray analysis, the drawing of which is presented in Figure 1. The notable feature is that two phthalimido groups in a pair of adjoining ligands are oriented to an axial position of the distored octahedral geometry around each rhodium, the reaction site with α-diazo compounds. The author has deposited atomic coordinates for this structure with the Cambridge Crystallographic Data Center.
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21
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0000719854
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For a diastereoselective intramolecular C-H insertion of α-diazo β-keto esters of chiral alcohol, see
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(1983)
J. Am. Chem. Soc.
, vol.105
, pp. 5935
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Taber1
Raman2
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23
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33845283264
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3), respectively, which were derived from diastereomerically pure β-keto esters obtained by transesterification of methyl (±)-3-phenyl-2-oxo-cyclopentane-1-carboxylate with (−)-menthol and a subsequent separation. and references cited therein
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(1987)
J. Am. Chem. Soc.
, vol.109
, pp. 6858
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Paquette1
Gilday2
Ra3
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24
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84918713698
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4-catalyzed cyclization of 2c furnished (S)-4 in 23% ee.
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25
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0000207511
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Although it has been demonstrated that diastereo- (trans/cis ratio) and enantioselectivity in catalytic, asymmetric cyclopropanation of olefins can be improved by increasing the steric bulk of the alcohol moiety of diazoacetates, such a dramatic effect on enantioselection has not previously been identified
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(1977)
Tetrahedron Lett.
, pp. 2599
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Aratani1
Yoneyoshi2
Nagase3
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27
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84986366730
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Semicorrin metal complexes as enantioselective catalysts. Part 2. Enantioselective cyclopropane formation from olefins with diazo compounds catalyzed by chiral (semicorrinato)copper complexes
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(1988)
Helvetica Chimica Acta
, vol.71
, pp. 1553
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Fritschi1
Leutenegger2
Pfaltz3
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31
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33845374322
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It is documented that phenyl and vinyl groups are inductively electron-withdrawing and so decrease the electron density of the adjacent C-H bond, rendering it reluctant to attack by the electrophilic rhodium-carbene species, A remarkable enhancement of the enantioselectivities with the aryl and vinyl substituents might be associated with their electronic properties, though no rate reduction of cyclization was experimentally observed.
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(1986)
J. Am. Chem. Soc.
, vol.108
, pp. 7686
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Taber1
Ruckle2
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32
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84918751121
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This research was supported in part by grants from Japan Research Foundation for Optically Active Compounds, Uehara Memorial Foundation, the Fujisawa Foundation, and the Ministry of Education, Science, and Culture of Japan. We are grateful to Misses H. Ishido and F. Taki for spectroscopic measurements.
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