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Volumn 20, Issue 35, 2014, Pages 11091-11100

Catalytic enantioselective amide allylation of isatins and its application in the synthesis of 2-oxindole derivatives spiro-fused to the α-methylene-γ-butyrolactone functionality

Author keywords

allylation; antitumor agents; asymmetric catalysis; lactones; spiro compounds

Indexed keywords

ALLYLATION; AMIDES; CATALYSIS; STEREOCHEMISTRY; SUBSTRATES;

EID: 84906781624     PISSN: 09476539     EISSN: 15213765     Source Type: Journal    
DOI: 10.1002/chem.201403357     Document Type: Article
Times cited : (46)

References (67)
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  • 44
    • 85013280598 scopus 로고    scopus 로고
    • 2=0.1116, GoF=1.228, and Flack absolute structure parameter=0.10(6) for 2582 reflections and 222 parameters.
    • 2=0.1116, GoF=1.228, and Flack absolute structure parameter=0.10(6) for 2582 reflections and 222 parameters.
  • 45
    • 85013329434 scopus 로고    scopus 로고
    • For the absolute stereochemistry of 3 h, the R configuration was assigned to the newly created stereogenic center by comparison of the optical rotation with that reported in the literature (see Ref. [13b]). The opposite stereochemical preference in addition to the observed very low enantioselectivity (25 % ee) can be interpreted in terms of inefficient chirality transfer from the chiral environment at the catalytic center.
    • For the absolute stereochemistry of 3 h, the R configuration was assigned to the newly created stereogenic center by comparison of the optical rotation with that reported in the literature (see Ref. [13b]). The opposite stereochemical preference in addition to the observed very low enantioselectivity (25 % ee) can be interpreted in terms of inefficient chirality transfer from the chiral environment at the catalytic center.
  • 50
    • 85013258294 scopus 로고    scopus 로고
    • The lower efficiency of the reaction than with the isatin substrates is probably responsible for intrinsic low reactivity of the acyclic ketoamide system, which would be attributed to the greater conformational flexibility. The ee value of P2 was determined by HPLC analysis with the Daicel Chiralpak IF.
    • The lower efficiency of the reaction than with the isatin substrates is probably responsible for intrinsic low reactivity of the acyclic ketoamide system, which would be attributed to the greater conformational flexibility. The ee value of P2 was determined by HPLC analysis with the Daicel Chiralpak IF.
  • 51
    • 85013308665 scopus 로고    scopus 로고
    • In the mechanistic studies with the hydrogen-containing additives, it was found that use of imidazole (1.2 equiv) had a detrimental effect on both the reactivity and enantioselectivity of the amide allylation to 3 g. In this case, only a sluggish and incomplete reaction took place over 72 h to result in the formation of 3 g with an isolated yield of 12 % as a completely racemic product.
    • In the mechanistic studies with the hydrogen-containing additives, it was found that use of imidazole (1.2 equiv) had a detrimental effect on both the reactivity and enantioselectivity of the amide allylation to 3 g. In this case, only a sluggish and incomplete reaction took place over 72 h to result in the formation of 3 g with an isolated yield of 12 % as a completely racemic product.
  • 52
    • 84906780993 scopus 로고    scopus 로고
    • 1H NMR spectroscopic studies allowed us to gain additional insight into the proposed transition-state structure. The details are given in the Supporting Information.
    • 1H NMR spectroscopic studies allowed us to gain additional insight into the proposed transition-state structure. The details are given in the Supporting Information.
  • 53
    • 85013345969 scopus 로고    scopus 로고
    • 2=0.1120, GoF=1.068, and Flack absolute structure parameter=0.1(3) for 1984 reflections and 155 parameters.
    • 2=0.1120, GoF=1.068, and Flack absolute structure parameter=0.1(3) for 1984 reflections and 155 parameters.
  • 56
    • 84906788219 scopus 로고    scopus 로고
    • Clearly, one can see that these types of compounds will be more easily accessed by the available amide allylation/lactonization sequence from the respective C5-halogenated isatins.
    • Clearly, one can see that these types of compounds will be more easily accessed by the available amide allylation/lactonization sequence from the respective C5-halogenated isatins.
  • 59
    • 85013313550 scopus 로고    scopus 로고
    • 2=0.0706, GoF=1.062, and Flack absolute structure parameter=0.020(12) for 3675 reflections and 191 parameters.
    • 2=0.0706, GoF=1.062, and Flack absolute structure parameter=0.020(12) for 3675 reflections and 191 parameters.
  • 60
    • 85013280586 scopus 로고    scopus 로고
    • 2=0.0636, GoF=1.027, and Flack absolute structure parameter=-0.028(18) for 3715 reflections and 192 parameters.
    • 2=0.0636, GoF=1.027, and Flack absolute structure parameter=-0.028(18) for 3715 reflections and 192 parameters.
  • 61
    • 85013282104 scopus 로고    scopus 로고
    • 2=0.0740, GoF=1.031, and Flack absolute structure parameter=0.049(6) for 2909 reflections and 217 parameters.
    • 2=0.0740, GoF=1.031, and Flack absolute structure parameter=0.049(6) for 2909 reflections and 217 parameters.
  • 62
    • 85013345960 scopus 로고    scopus 로고
    • 2=0.1052, GoF=1.005, and Flack absolute structure parameter=-0.02(2) for 3532 reflections and 208 parameters.
    • 2=0.1052, GoF=1.005, and Flack absolute structure parameter=-0.02(2) for 3532 reflections and 208 parameters.
  • 63
    • 85013309806 scopus 로고    scopus 로고
    • 2=0.1031, GoF=1.108, and Flack absolute structure parameter=0.09(2) for 2988 reflections and 166 parameters.
    • 2=0.1031, GoF=1.108, and Flack absolute structure parameter=0.09(2) for 2988 reflections and 166 parameters.
  • 64
    • 85013258262 scopus 로고    scopus 로고
    • 2=0.0563, GoF=1.039, and Flack absolute structure parameter=0.064(8) for 1717 reflections and 164 parameters.
    • 2=0.0563, GoF=1.039, and Flack absolute structure parameter=0.064(8) for 1717 reflections and 164 parameters.
  • 65
    • 85013280571 scopus 로고    scopus 로고
    • 2=0.1076, GoF=1.081, and Flack absolute structure parameter=0.065(5) for 2109 reflections and 164 parameters.
    • 2=0.1076, GoF=1.081, and Flack absolute structure parameter=0.065(5) for 2109 reflections and 164 parameters.
  • 66
    • 84906786141 scopus 로고    scopus 로고
    • On the basis of these results, the absolute configurations of 4 g - i, which were left unassigned, could be determined to be S by distinct correlations with the chiral HPLC analyses of the corresponding cyclization products with those of the authentic samples of (S)- 6 a - 8 a, respectively.
    • On the basis of these results, the absolute configurations of 4 g-i, which were left unassigned, could be determined to be S by distinct correlations with the chiral HPLC analyses of the corresponding cyclization products with those of the authentic samples of (S)- 6 a-8 a, respectively.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.