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Volumn 12, Issue 26, 2006, Pages 6910-6929

Asymmetric allylic substitution catalyzed by C1-symmetrical complexes of molybdenum: Structural requirements of the ligand and the stereochemical course of the reaction

Author keywords

Allylic substitution; Asymmetric catalysis; Chiral ligands; Deuterium labeling; Memory effect; Molybdenum

Indexed keywords

ALLYLIC SUBSTITUTION; ASYMMETRIC CATALYSIS; CHIRAL LIGANDS; DEUTERIUM LABELING;

EID: 33748550311     PISSN: 09476539     EISSN: 15213765     Source Type: Journal    
DOI: 10.1002/chem.200501574     Document Type: Article
Times cited : (73)

References (114)
  • 25
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    • note
    • a) For an earlier observation by us of an asymmetric induction with Mo-bisoxazoline complexes, see ref. [4]. Since this experiment required a high catalyst loading, it was only cited in a footnote.
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  • 46
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    • For the method, see ref. [11b]
    • For the method, see ref. [11b].
  • 47
    • 33748552577 scopus 로고    scopus 로고
    • note
    • The structure of (R)-(-)-12a was confirmed by single crystal X-ray analysis (see the Supporting Information for details).
  • 49
    • 33748556441 scopus 로고    scopus 로고
    • 3P method failed
    • 3P method failed.
  • 56
    • 33748576484 scopus 로고    scopus 로고
    • note
    • 3] complex as the catalyst for allylic substitution, see ref. [3h].
  • 57
    • 33748521462 scopus 로고    scopus 로고
    • note
    • 3]}. b) This behavior seems to suggest that a tridentate coordination of the metal by 12 is required to generate an active catalyst.
  • 58
    • 33748539608 scopus 로고    scopus 로고
    • note
    • [8b]
  • 60
    • 33748531527 scopus 로고    scopus 로고
    • note
    • [28] respectively, so that direct comparison is not straightforward.
  • 61
    • 33748538240 scopus 로고    scopus 로고
    • note
    • [10]
  • 62
    • 0001083488 scopus 로고
    • 0-catalyzed allylic substitution. For selected examples, see the following: a) H. Frisell, B. Åkermark, Organometallics 1995, 14, 561;
    • (1995) Organometallics , vol.14 , pp. 561
    • Frisell, H.1    Åkermark, B.2
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    • 1642576013 scopus 로고    scopus 로고
    • Subsequent work involving use of enantiomerically enriched (>90% ee) deuterated substrates and analysis of the solution-phase structure and reactivity of deuterated samples of C by NMR, has led to the conclusion that C is attacked "internally", that is, via a retention pathway, to give the major product enantiomer. With the matched enantiomer of branched substrate the reaction would therefore proceed with overall net retention, via a two-fold retention mechanism [a) G. C. Lloyd-Jones, S. W. Krska, D. L. Hughes, L. Gouriou, V. D. Bonnet, K. Jack, Y. Sun, R. A. Reamer, J. Am. Chem. Soc. 2004, 126, 702;
    • (2004) J. Am. Chem. Soc. , vol.126 , pp. 702
    • Lloyd-Jones, G.C.1    Krska, S.W.2    Hughes, D.L.3    Gouriou, L.4    Bonnet, V.D.5    Jack, K.6    Sun, Y.7    Reamer, R.A.8
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    • note
    • 3], respectively.
  • 69
    • 33748572162 scopus 로고    scopus 로고
    • note
    • [15b] (90% ee, 72% yield, and 8:1 regioisomer ratio).
  • 70
    • 33748566706 scopus 로고    scopus 로고
    • note
    • The reaction of cinnamyl carbonate 4 with sodium dimethyl malonate in the presence of [Mo]/19 proved to proceed with ordinary kinetics, namely with no induction period and no appreciable decomposition or isomerization of products; the reaction was complete within ca 5 h.
  • 71
    • 33748552912 scopus 로고    scopus 로고
    • note
    • The regioselectivities of the catalytic and stoichiometric (in [Mo]/19) reaction turned out to differ marginally (83:17 vs 90:10); the catalytic version was faster.
  • 72
    • 33748534377 scopus 로고    scopus 로고
    • note
    • Cinnamyl carbonate 4 and the corresponding bromide provided almost identical results (i.e., regioselectivity and yields) in stoichiometric (in [Mo]/19) reactions, (90:10, 36% and 89:11, 39%, respectively). The catalytic reactions cannot be compared since cinnamyl bromide undergoes a non-catalytic reaction, which provides solely the linear product.
  • 73
    • 33748572841 scopus 로고    scopus 로고
    • note
    • 1-Phenyl-but-1-en-3-yl acetate does not react with sodium dimethyl malonate under molybdenum catalysis, showing that molybdenum requires primary allylic esters.
  • 75
    • 33748573881 scopus 로고    scopus 로고
    • note
    • The good reactivity of ligand 18 lends additional credence to monodeprotonation. Here, in contrast to the other ligands, the three ligating centers must take a meridional arrangement (mer) and that could explain the lack of enantioselectivity, which is determined by the turn in the ligand forming facial (fac) coordination of the three ligating centers around metal.
  • 85
    • 0000240127 scopus 로고
    • For leading references to "memory effects" in Pd-catalyzed allylic alkylations see: a) J. C. Fiaud, J. L. Malleron, Tetrahedron Lett. 1981, 22, 1399;
    • (1981) Tetrahedron Lett. , vol.22 , pp. 1399
    • Fiaud, J.C.1    Malleron, J.L.2
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    • 33748553581 scopus 로고    scopus 로고
    • note
    • However, it should be noted that there is no direct correlation between the magnitude of the various kinetic resolution factors and the overall degree of asymmetric induction with 12 a (s = 3), 12 c (s = 2), and 8 (s = 10).
  • 101
    • 23544470180 scopus 로고    scopus 로고
    • Rearrangements of allylpalladium and Related derivatives
    • (Ed.: E. Negishi), Wiley, New York
    • For an overview of Pd-catalyzed rearrangements, see: b) P. Kočovský, I. Starý, Rearrangements of Allylpalladium and Related Derivatives in Handbook of Organopalladium Chemistry for Organic Synthesis, Vol. II (Ed.: E. Negishi), Wiley, New York, 2002, p. 2011;
    • (2002) Handbook of Organopalladium Chemistry for Organic Synthesis , vol.2 , pp. 2011
    • Kočovský, P.1    Starý, I.2
  • 103
    • 37049076495 scopus 로고
    • a) F. Toda, Y. Tohi, J. Chem. Soc. Chem. Commun. 1993, 1238; b) this procedure involved enantioselective co-crystallization of 35 with enantiomerically pure α,α,α,′,α′- tetraphenyl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol (TADDOL) from an aqueous-surfactant solution, followed by liberation of the free 35 in 85-95 % ee by distillation. Repeated recycling using both enantiomers of TADDOL afforded both enantiomers of 35 in high ee and in reasonable yields.
    • (1993) J. Chem. Soc. Chem. Commun. , vol.1238
    • Toda, F.1    Tohi, Y.2
  • 104
    • 33748550555 scopus 로고    scopus 로고
    • note
    • The ee values were determined by chiral GC or HPLC; the absolute configurations of the corresponding carbonates 37 c was determined by optical rotation, which then confirms the absolute configuration of the precursors and other products, e.g., the acetate.
  • 106
    • 33748541516 scopus 로고    scopus 로고
    • note
    • 6], in the initial stages of the reaction due to the pro-catalyst formation under ambient temperature conditions. For a full discussion, see the main text.
  • 107
    • 33748521779 scopus 로고    scopus 로고
    • note
    • 2-symmetric bispicolinamide ligands such as 8.
  • 114
    • 33748565226 scopus 로고    scopus 로고
    • note
    • 2H signals are reported as though 39 were a single compound, except for the H at the chiral center.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.