메뉴 건너뛰기




Volumn , Issue 7, 2005, Pages 1271-1282

Asymmetric dihydroxylation with recoverable cinchona alkaloid derivatives: A warning note and an improved, insoluble polymer-bound ligand architecture

Author keywords

Asymmetric catalysis; Dihydroxylation; Osmium; Supported catalysts

Indexed keywords

ALKALOID DERIVATIVE; ALKENE; CINCHONA ALKALOID; COPOLYMER; LIGAND; ORGANIC COMPOUND; OSMIUM; POLYMER;

EID: 16444366385     PISSN: 1434193X     EISSN: None     Source Type: Journal    
DOI: 10.1002/ejoc.200400752     Document Type: Article
Times cited : (20)

References (89)
  • 3
    • 0001216677 scopus 로고    scopus 로고
    • (Eds.: E. N. Jacobsen, A. Pfaltz, H. Yamamoto), Springer, Berlin, chapter 20
    • c) I. E. Markò, J. S. Svendsen, in Comprehensive Asymmetric Catalysis (Eds.: E. N. Jacobsen, A. Pfaltz, H. Yamamoto), Springer, Berlin, 1999, vol. 2, chapter 20;
    • (1999) Comprehensive Asymmetric Catalysis , vol.2
    • Markò, I.E.1    Svendsen, J.S.2
  • 7
    • 0000600955 scopus 로고    scopus 로고
    • For approaches different from those discussed in this paper, including also the recovery of osmium compounds, see: a) S. Kobayashi, T. Ishida, R. Akiyama, Org. Lett. 2001, 3, 2649-2652;
    • (2001) Org. Lett. , vol.3 , pp. 2649-2652
    • Kobayashi, S.1    Ishida, T.2    Akiyama, R.3
  • 46
    • 0036809927 scopus 로고    scopus 로고
    • k) For a review, see: C. E. Song, S. Lee, Chem. Rev. 2002, 102, 3495-3524.
    • (2002) Chem. Rev. , vol.102 , pp. 3495-3524
    • Song, C.E.1    Lee, S.2
  • 50
    • 0030824025 scopus 로고    scopus 로고
    • c) H. Han, K. D. Janda, Angew. Chem. Int. Ed. Engl. 1997, 36, 1731-1733, Angew. Chem. 1997, 109, 1835-1837;
    • (1997) Angew. Chem. , vol.109 , pp. 1835-1837
  • 52
    • 0030854968 scopus 로고    scopus 로고
    • d) C. Bolm, A. Gerlach, Angew. Chem. Int. Ed. Engl. 1997, 36, 741-743, Angew. Chem. 1997, 109, 773-775;
    • (1997) Angew. Chem. , vol.109 , pp. 773-775
  • 58
    • 16444363046 scopus 로고    scopus 로고
    • Pat. WO 9835927, 1998
    • a) K. D. Janda, H. Han, Pat. WO 9835927, 1998;
    • Janda, K.D.1    Han, H.2
  • 59
    • 16444386404 scopus 로고    scopus 로고
    • U.S. Pat. 5968867, 1999
    • b) C. E. Song, J. W. Yang, U. S. Pat. 5968867, 1999;
    • Song, C.E.1    Yang, J.W.2
  • 61
    • 16444362056 scopus 로고    scopus 로고
    • Pat. WO 2002066159, 2002
    • d) A. Chesney, W. P. Hems, Pat. WO 2002066159, 2002;
    • Chesney, A.1    Hems, W.P.2
  • 70
    • 33748983103 scopus 로고
    • D. J. Berrisford, C. Bolm, K. B. Sharpless, Angew. Chem. Int. Ed. Engl. 1995, 34, 1059-1070, Angew. Chem. 1995, 107, 1159-1170.
    • (1995) Angew. Chem. , vol.107 , pp. 1159-1170
  • 73
    • 16444369509 scopus 로고    scopus 로고
    • note
    • It should be noted that, because of LAE, the chiral ligand concentration also affects the reaction rate. In fact, in the runs with variable amounts of 5 the expected trends in the catalytic activity were generally observed for both styrene and 1-phenyl-cyclohexene, but they are not discussed in detail here due to the difficulty of obtaining good-quality kinetic data in the biphasic system under study. In any case, >95% conversion values could be obtained in 16 h, regardless of the alkaloid concentration.
  • 74
    • 16444366050 scopus 로고    scopus 로고
    • Ph. D. Dissertation, Univ. of Pisa
    • A. Mandoli, Ph. D. Dissertation, Univ. of Pisa, 1998.
    • (1998)
    • Mandoli, A.1
  • 77
    • 16444382624 scopus 로고    scopus 로고
    • note
    • For instance, the last step of a hydroboration/oxidation/Williamson alkylation sequence afforded an intractable mixture of products, possibly due to a competitive nitrogen quaternization followed by base-promoted cleavage of the quinuclidine structure. An alternative route, based on the initial olefin cross-metathesis with 10-undecene-1-ol followed by hydrogenation, resulted in low conversions in both steps under a range of conditions.
  • 78
    • 0026340731 scopus 로고
    • Even if it has been shown that substrates containing thioether groups can be dihydroxylated without affecting the sulfur moiety, previous work in this group indicated that the omission of the oxidation step causes a retardation of AD when the supported ligands are employed in catalysis. The presence of sulfone groups in 12 and 13 is assumed by analogy with solution-phase behavior: W. Priebe, G. Grynkiewicz, Tetrahedron Lett. 1991, 32, 7353-7356.
    • (1991) Tetrahedron Lett. , vol.32 , pp. 7353-7356
    • Priebe, W.1    Grynkiewicz, G.2
  • 80
    • 16444378930 scopus 로고    scopus 로고
    • note
    • The glass frit employed had an average porosity of 10-16 μm, but further filtration of the solution containing the leached alkaloid through a 0.2 μm membrane did not cause the absorbance to change appreciably. Therefore, the size of the dissolved species is, at most, in the sub-micron range.
  • 81
    • 16444365648 scopus 로고    scopus 로고
    • note
    • 2O solvent system was also observed in the case of the modified architecture of 12 and 13a,b. At present, however, the complex nature of the triphasic system under investigation makes it difficult to ascertain if this behavior is related to a slow base-induced fragmentation of the covalent linker or to the intrinsic heterogeneity of the polymeric materials, that could lead to a medium-dependent release of minor amounts of trapped monomers and soluble oligomers into solution.
  • 82
    • 16444385319 scopus 로고    scopus 로고
    • note
    • 4 volatilization, the procedure discussed in the text was preferentially used in this work.
  • 83
    • 16444365510 scopus 로고    scopus 로고
    • note
    • In response to a referee's comment, it must be noted that because the focus of this study was on the recycling of the chiral ligand, no detailed investigation was carried out to asses the extent of metal leaching or to optimize the recovery of osmium compounds. Nonetheless, after extensive washing with water (required to remove the abundant precipitate of inorganic salts) a very low catalytic activity in the AD reaction was obtained for the recovered polymeric material, thereby suggesting a substantial metal loss. This conclusion is in agreement with previous observations.
  • 84
    • 16444376605 scopus 로고    scopus 로고
    • note
    • Effectively, because the achievement of a certain level of enantioselectivity is dependent on both the ligand and the osmium concentration, it could be speculated that the higher ee values obtained in the supposed heterogeneous runs are a consequence of the trapping of most of the osmium by the polymeric ligand in a catalytically inactive form. This would leave a small residual amount of active metal species in solution, for which the tiny amount of leached alkaloid could prove sufficient in promoting a highly stereoselective homogeneous process. This hypothesis can, however, be discarded in view of the kinetic data presented. In particular, the dihydroxylation rate in the presence of 12 appears to be not lower than in the control experiments, thus demonstrating that the concentration of catalytically active osmium species attained in the former situation is at least comparable with that employed in the latter case.
  • 85
    • 0010324782 scopus 로고    scopus 로고
    • The possibility of running the AD, for preparative purposes, with reduced amounts of both the chiral ligand and the osmium compound has been noted before: J. M. McIntosh, E. J. Kiser, Synlett 1997, 1283-1284.
    • (1997) Synlett , pp. 1283-1284
    • McIntosh, J.M.1    Kiser, E.J.2
  • 87
    • 16444374618 scopus 로고    scopus 로고
    • note
    • It must be noted that in the preparation of 8 and 11 prolonged heating above 50 °C, in the presence of NaH, should be avoided to prevent the formation of by-products, presumably having epimeric structures (by NMR spectroscopy).
  • 89
    • 0037020377 scopus 로고    scopus 로고
    • D. C. Sherrington, A. Lanver, H.-G. Schmalz, B. Wilson, X.-W. Ni, S. Yuan, Angew. Chem. Int. Ed. 2002, 41, 3656-3659, Angew. Chem. 2002, 114, 3808-3811.
    • (2002) Angew. Chem. , vol.114 , pp. 3808-3811


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.