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Volumn 128, Issue 44, 2006, Pages 14293-14305

Mechanistic study of hydrogen transfer to imines from a hydroxycyclopentadienyl ruthenium hydride. Experimental support for a mechanism involving coordination of imine to ruthenium prior to hydrogen transfer

Author keywords

[No Author keywords available]

Indexed keywords

CHEMICAL BONDS; COMPLEXATION; ELECTRONS; HYDROGEN; ISOTOPES; PROTONS;

EID: 33750702516     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja061494o     Document Type: Article
Times cited : (117)

References (64)
  • 34
    • 33750693484 scopus 로고    scopus 로고
    • note
    • Casey has prepared this complex in a very similar way; see ref 13.
  • 35
    • 33750698018 scopus 로고    scopus 로고
    • note
    • Except for very electron-rich N-alkyl imines, which formed thermostable ruthenium amine complexes that inhibited further catalysis.
  • 40
    • 33750725190 scopus 로고    scopus 로고
    • note
    • However with a methyl group on the nitrogen, an amine complex was observed.
  • 42
    • 33750726834 scopus 로고    scopus 로고
    • Dissertation, Stockholm University
    • Samec, J. S. M. Dissertation, Stockholm University, 2005.
    • (2005)
    • Samec, J.S.M.1
  • 43
    • 33750695397 scopus 로고    scopus 로고
    • note
    • When the reaction was run in THF-dg the complex appeared as diastereomeres with doublets at δ 0.88 and 0.92; both had a coupling constant of J = 6.5 Hz.
  • 45
    • 33750718576 scopus 로고    scopus 로고
    • note
    • Seven and six different experiments, respectively, were run for RuHOH and RuDOD individually.
  • 46
    • 33750714150 scopus 로고    scopus 로고
    • note
    • Casey's group has also performed a kinetic isotope study on different aldimines and found that very electron-deficient imines behave as aldehydes and electron-rich imines give inverse isotope effects. See ref 15.
  • 47
    • 33750726167 scopus 로고    scopus 로고
    • note
    • It has been established that dehydrogenation of amine 4 is much slower than hydrogen transfer from hydride 2 to the quinone when an excess of quinone is used. Furthermore, the former dehydrogenation step is an irreversible step under these conditions.
  • 48
    • 33750714505 scopus 로고    scopus 로고
    • note
    • When the α-carbon is deuterated in amine 4, the transfer of N-H and N-D will both be fast in relation to C-D cleavage and cannot be distinguished. On the other hand when the α-carbon is nondeuterated, the α-carbon-hydrogen bond cleavage is >3 times faster compared to the deuterated case and the difference in rate between transfer of the N-H and N-D can be partly seen.
  • 49
    • 33750738313 scopus 로고    scopus 로고
    • note
    • It was not possible to detect any free amine PhCH(Me)NHMe from reduction of imine 14 in the NMR spectrum.
  • 50
    • 33750691440 scopus 로고    scopus 로고
    • note
    • 13C NMR for detection of 3 in 2 (see Supporting Information). However, the detection limit of the dimer is about 2%. With 2% of 3 up to ca. 4% of trapping complex could be formed.
  • 52
    • 33750734010 scopus 로고    scopus 로고
    • note
    • 10 = cyclohexylidene) with 2 gave a signal at δ -297 ppm.
  • 53
    • 33750731720 scopus 로고    scopus 로고
    • note
    • To confirm that this signal was not a protonated form of 18 a control experiment was run where the imine was mixed with TFA; no signal at δ -296 ppm was observed.
  • 58
    • 33750730011 scopus 로고    scopus 로고
    • Ionic hydrogenations
    • de Vries, J. G., Eds.; Elsevier, C. J.: in press (ISBN 3-527-31161-0)
    • (d) Bullock R. M. Ionic Hydrogenations. In Handbook of Homogeneous Hydrogenation; de Vries, J. G., Eds.; Elsevier, C. J.: in press (ISBN 3-527-31161-0).
    • Handbook of Homogeneous Hydrogenation
    • Bullock, R.M.1
  • 62
    • 33750723878 scopus 로고    scopus 로고
    • note
    • For some of the intermediate structures, but not the TS. One single THF molecule was added.
  • 63
    • 33750738159 scopus 로고    scopus 로고
    • Submitted for publication
    • The calculations will be presented in a separate paper: Privalov, T.; Samec, J. S. M.; Bäckvall, J. E. Submitted for publication.
    • Privalov, T.1    Samec, J.S.M.2    Bäckvall, J.E.3


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.