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Volumn 20, Issue 10, 2001, Pages 2102-2108

Cis-selective asymmetric cyclopropanation of olefins catalyzed by five-coordinate [RuCl(PNNP)]+ complexes

Author keywords

[No Author keywords available]

Indexed keywords

CIS SELECTIVE ASYMMETRIC CYCLOPROPANATION; DIASTEREOMERIC AGGREGATES; DIAZOESTERS; ENENTIOSELECTIVITY; MOLECULAR MODELLING CALCULATIONS; PUTATIVE CARBENE INTERMEDIATE; STRERIC CONSTRAINTS;

EID: 0035858945     PISSN: 02767333     EISSN: None     Source Type: Journal    
DOI: 10.1021/om010020p     Document Type: Article
Times cited : (76)

References (49)
  • 2
    • 0001403071 scopus 로고    scopus 로고
    • Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer: Berlin; Chapter 16
    • (b) Doyle M. P.; McKervey, M. A.; Ye, T. Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer: Berlin, 1999; Chapter 16, pp. 513-603.
    • (1999) Comprehensive Asymmetric Catalysis , pp. 513-603
    • Doyle, M.P.1    McKervey, M.A.2    Ye, T.3
  • 10
  • 25
    • 0011483970 scopus 로고    scopus 로고
    • note
    • No reaction is observed at room temperature in the presence of 2b. A slight catalytic activity can be observed with the dichloro derivative 2b in dichloroethane at reflux (43% conversion, 3% yield. 86:14 cis-to-trans ratio), but 1 and 2 are formed with low enantioselectivity (4 and 2% ee, respectively), suggesting that the largest contribution to the reaction is due to the uncatalyzed (thermic) reaction.
  • 26
    • 0011484736 scopus 로고    scopus 로고
    • note
    • GC analysis of the coupling products is inadeuate, as ethyl diazoacetate dimerizes to fumarate and maleate during the chromatographic analysis.
  • 27
    • 0011436496 scopus 로고    scopus 로고
    • note
    • Decomposition products of 3, or the uncatalyzed thermal decomposition of the diazoester, can be responsible for the formation of 6 and 7 during cyclopropanation.
  • 34
    • 0011392642 scopus 로고    scopus 로고
    • note
    • In contrast, the reaction of 3b with ethyl adiazoacetate at -50°C gives two different carbene complexes 11b′ and 11b″. In both complexes the carbene ligand is cis to both phosphines, as indicated by the P,C(carbene) coupling constants (see Experimental Part). Thus, we assume that these species are the two cis-β isomers featuring a trans C-Ru-N arrangement.
  • 39
    • 0011393194 scopus 로고    scopus 로고
    • note
    • In a MM study of the rhodium(II) carbamidato system, Doyle has reported similar considerations.
  • 40
    • 0011446727 scopus 로고    scopus 로고
    • note
    • The only exception to this general assumption we are aware of has been suggested by Kodadek to explain the cis selectivity observed with rhodium porphyrins. According to his model, the olefin attacks the carbene with the C=C double bond perpendicular to the M-C vector and parallel to the plane of the porphyrin. However, the olefin rotates before reaching the transition state, and the side-on approach also leads to an end-on transition state in which both double bonds are parallel.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.