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Volumn 15, Issue 14, 2004, Pages 2139-2150

Cationic Rh-bisphosphine-diolefin complexes as precatalysts for enantioselective catalysis - What information do single crystal structures contain regarding product chirality?

Author keywords

[No Author keywords available]

Indexed keywords

ALKADIENE; CATION; PHOSPHINE DERIVATIVE; RHODIUM;

EID: 3843065835     PISSN: 09574166     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetasy.2004.06.036     Document Type: Review
Times cited : (32)

References (79)
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    • For another example, not yet in the CSD, see also: L. Dahlenburg Eur. J. Inorg. Chem. 23 2003 2733 2747
    • (2003) Eur. J. Inorg. Chem. , vol.23 , pp. 2733-2747
    • Dahlenburg, L.1
  • 25
    • 3843073905 scopus 로고    scopus 로고
    • note
    • In this work only bidentate chelating bisphosphines are considered, not P,N- or N,N-donor ligands. Furthermore, complexes with two chelating bisphosphines and phosphine ligands that already contain the coordinating olefins are not taken into account
  • 26
    • 3843094599 scopus 로고    scopus 로고
    • note
    • Complexes with achiral ligands (entries 1-8) crystallize in achiral space groups. Consequently, beside complexes with λ-conformation and distortion of the diolefin in a specific direction the enantiomeric δ-conformer via the symmetry element of point mirror with the opposite sense of rotation of the diolefin is present in the crystal. In the table the specification for the diolefin orientation always applies to the λ-conformation
  • 28
    • 84862397839 scopus 로고    scopus 로고
    • Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited at the Cambridge Crystallographic Data Centre as supplementary publication no, CCDC-236784 for entry 2, CCDC-236785 for entry 3, 236786 for entry 10, 236787 for entry 24, 236782 for entry 32, 236783 for entry 33 (concerning Table 1) and CCDC-163842 for entry 3 (Table 3; Fig. 8). Copies of the data can be obtained, free of charge, on application to The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: int. code +44 (1223) 336-033; e-mail: deposit@ccdc.cam.ac.uk ; web, http://www.ccdc.cam.ac.uk)
  • 31
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    • note
    • Disorder of COD; positions I and II
  • 51
    • 3843067357 scopus 로고    scopus 로고
    • note
    • This trend, however, is not changed by the fact that for examples with several cations in the asymmetric unit partly larger differences in the discussed lengths are observed
  • 54
    • 25444471909 scopus 로고    scopus 로고
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    • note
    • Unfortunately, there are not enought structures existing of five-membered ring chelates discussed in this paper that occur with both the diolefins to prove the hypothesis. Additionally, this assertion does not apply to two out of six examples from Table 1 (no 4/5 and 29/30); the NBD complexes of DCPE and BASPHOS, respectively, show slightly larger tetrahedral distortion than the appropriate COD complexes. The reasons for the unexpected behaviour is unclear but in case of BASPHOS the apparently large tetrahedral distortion of 22° is approximately to one half caused by the fact that according to Figure 7 an additional rotation of the NBD around the x-axis appears; the angle between the centre of the phosphorus atoms, rhodium and the centre of the centroids is only 171°
  • 63
    • 3843054318 scopus 로고    scopus 로고
    • note
    • Examples containing more than two cations in the asymmetric unit and in which two of the diolefins each exhibit a contrary direction of rotation are not taken into account: CUQJIV, VAZDUV and SULMUH
  • 64
    • 3843117383 scopus 로고    scopus 로고
    • note
    • Only these two conformations are distinguished, disturbances of those conformations described in detail in Ref. d are not taken into further consideration
  • 66
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    • (1982) Science , vol.217 , pp. 401-407
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    • J.D. Morrison Academic Orlando
    • J. Halpern J.D. Morrison Asymmetric Synthesis Vol. 5 1985 Academic Orlando 41 69
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    • Landis, C.R.1
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    • note
    • As a kinetic phenomenon the enantioselectivity is determined as the ratio of the enantiomeric products, from the ratio of reactivity of the diastereomeric substrate complexes as well as the ratio of the concentration of these intermediates and thus is dependent on several possible reaction pathways. The selectivity experimentally obtained is not only the result of the potential of the catalyst intrinsically present and determined by the chiral ligand, but also the result of external parameters such as hydrogen pressure and temperature. In other words, a chiral ligand is a necessary but not sufficient condition for stereoselection


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.