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Volumn 75, Issue 3, 2010, Pages 825-838

An enantioselective synthetic route toward second-generation light-driven rotary molecular motors

Author keywords

[No Author keywords available]

Indexed keywords

CHEMICAL EQUATIONS; ENANTIOSELECTIVE; ENZYMATIC RESOLUTIONS; HYDRAZONES; METHOXY; MOLECULAR MOTORS; OPTICALLY ACTIVE; RECRYSTALLIZATIONS; ROTARY CYCLE; SPECTROSCOPIC TECHNIQUE; STEREOGENIC CENTERS; SYNTHETIC ROUTES; THERMAL ISOMERIZATIONS; THIOKETONE;

EID: 75749092979     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo902348u     Document Type: Article
Times cited : (27)

References (67)
  • 4
    • 0013217441 scopus 로고    scopus 로고
    • Schliwa, M, Ed, Wiley-VCH: Weinheim, Germany
    • Molecular Motors Schliwa, M., Ed.; Wiley-VCH: Weinheim, Germany, 2003.
    • (2003) Molecular Motors
  • 8
    • 34548760154 scopus 로고    scopus 로고
    • For a comprehensive review, see
    • For a comprehensive review, see: Feringa, B. L. J. Org. Chem. 2007, 72, 6635-6652.
    • (2007) J. Org. Chem , vol.72 , pp. 6635-6652
    • Feringa, B.L.1
  • 23
    • 75749114916 scopus 로고    scopus 로고
    • A similar finding about the effect of substituents on rotational barriers was found by Kelly and co-workers in their research on molecular ratchets increasing the size of the pawl of a ratchet lowered the barrier to rotation. Their explanation for this observation is that a larger pawl increases the energy of the ground state of the molecule, thus bringing it closer to the rotation energy barrier. See: Kelly, T. R, Sestelo, J. P, Tellitu, I. J. Org. Chem. 1998, 63, 3655-3665
    • A similar finding about the effect of substituents on rotational barriers was found by Kelly and co-workers in their research on molecular ratchets increasing the size of the "pawl" of a ratchet lowered the barrier to rotation. Their explanation for this observation is that a larger pawl increases the energy of the ground state of the molecule, thus bringing it closer to the rotation energy barrier. See: Kelly, T. R.; Sestelo, J. P.; Tellitu, I. J. Org. Chem. 1998, 63, 3655-3665.
  • 36
    • 70349970829 scopus 로고    scopus 로고
    • For a catalytic asymmetric synthesis of overcrowded alkenes, see
    • For a catalytic asymmetric synthesis of overcrowded alkenes, see: Hojo, D.; Noguchi, K.; Tanaka, K. Angew. Chem., Int. Ed. 2009, 48, 8129-8132.
    • (2009) Angew. Chem., Int. Ed , vol.48 , pp. 8129-8132
    • Hojo, D.1    Noguchi, K.2    Tanaka, K.3
  • 37
    • 71749107562 scopus 로고    scopus 로고
    • While this paper was under consideration, Tietze et al. published an attractive asymmetric catalytic synthesis of chiral overcrowded alkenes that are structurally analogous to second-generation molecular motors. See: Tietze, L. F, Düfert, A, Lotz, F, Sölter, L, Oum, K, Lenzer, T, Beck, T, Herbst-Irmer, R. J. Am. Chem. Soc. 2009, 131, 17879-17884
    • While this paper was under consideration, Tietze et al. published an attractive asymmetric catalytic synthesis of chiral overcrowded alkenes that are structurally analogous to second-generation molecular motors. See: Tietze, L. F.; Düfert, A.; Lotz, F.; Sölter, L.; Oum, K.; Lenzer, T.; Beck, T.; Herbst-Irmer, R. J. Am. Chem. Soc. 2009, 131, 17879-17884.
  • 48
    • 75749155183 scopus 로고    scopus 로고
    • 29 The absolute configuration of ketone 10 (as well as that of the successive compounds ketone 4, TBDMS hydrazone 11, and alkenes 5, 6, and 7) was confirmed by X-ray crystallography with refinement of the Flack parameter of alkene 5.
    • 29 The absolute configuration of ketone 10 (as well as that of the successive compounds ketone 4, TBDMS hydrazone 11, and alkenes 5, 6, and 7) was confirmed by X-ray crystallography with refinement of the Flack parameter of alkene 5.
  • 50
    • 75749083052 scopus 로고    scopus 로고
    • 13th ed, O'Neil, M. J, Smith, A, Heckelman, P. E, Budavari, S, Eds, Merck & Co, Inc, Whitehouse Station, NJ
    • The Merck Index, An Encyclopaedia of Chemicals, Drugs, and Biologicals, 13th ed.; O'Neil, M. J., Smith, A., Heckelman, P. E., Budavari, S., Eds.; Merck & Co., Inc.: Whitehouse Station, NJ, 2001; pp 851-852.
    • (2001) The Merck Index, An Encyclopaedia of Chemicals, Drugs, and Biologicals , pp. 851-852
  • 51
    • 75749113464 scopus 로고    scopus 로고
    • The presented procedure does not provide bis-TBDMS hydrazine in a yield better than the procedure of Furrow and Myers,26 as the formation of bis-TBDMS hydrazine under the described conditions only goes to 80% completion, and at least two distillations are needed to obtain pure bis-TBDMS hydrazine. The presented procedure, however, does not involve the heating of anhydrous hydrazine. Therefore, it can be regarded as a safer alternative, more suitable for the large-scale preparation of bis-TBDMS hydrazine in a laboratory environment
    • 26 as the formation of bis-TBDMS hydrazine under the described conditions only goes to 80% completion, and at least two distillations are needed to obtain pure bis-TBDMS hydrazine. The presented procedure, however, does not involve the heating of anhydrous hydrazine. Therefore, it can be regarded as a safer alternative, more suitable for the large-scale preparation of bis-TBDMS hydrazine in a laboratory environment.
  • 52
    • 75749123625 scopus 로고    scopus 로고
    • Although the presented procedure avoids the use of anhydrous hydrazine, suitable safety precautions should still be taken. It is strongly recommended to perform the preparation of bis-TBDMShydrazine behind a safety blast shield
    • Caution: Although the presented procedure avoids the use of anhydrous hydrazine, suitable safety precautions should still be taken. It is strongly recommended to perform the preparation of bis-TBDMShydrazine behind a safety blast shield.
    • Caution
  • 53
    • 75749086160 scopus 로고    scopus 로고
    • Furrow and Myers screened a broad range of different Lewis acid catalysts and found Sc(OTf)3 to be the most effective; see ref 26
    • 3 to be the most effective; see ref 26.
  • 54
    • 75749090154 scopus 로고    scopus 로고
    • Furrow and Myers have successfully employed diethyl ether as a cosolvent in some of their reactions to prepare TBDMS-protected hydrazone derivatives
    • Furrow and Myers have successfully employed diethyl ether as a cosolvent in some of their reactions to prepare TBDMS-protected hydrazone derivatives.
  • 55
    • 75749139458 scopus 로고    scopus 로고
    • We were not able to find conditions for the separation of (S)-5 and triphenylphosphine sulfide with regular silica gel or aluminum oxide.
    • We were not able to find conditions for the separation of (S)-5 and triphenylphosphine sulfide with regular silica gel or aluminum oxide.
  • 58
    • 75749094922 scopus 로고    scopus 로고
    • We believe that the observed higher stability with TLC silica gel (Analtech UNIPLATE, 2000 μm) could be the result of its higher degree of purity, which would cause it to contain less acidic impurities than silica gel used for column chromatography SiliCycle SiliaFlash P60, 40-63 μm
    • We believe that the observed higher stability with TLC silica gel (Analtech UNIPLATE, 2000 μm) could be the result of its higher degree of purity, which would cause it to contain less acidic impurities than silica gel used for column chromatography (SiliCycle SiliaFlash P60, 40-63 μm).
  • 60
    • 75749115311 scopus 로고    scopus 로고
    • The small absorption observed at 4.10 ppm originates from a trace amount of dichloromethane
    • The small absorption observed at 4.10 ppm originates from a trace amount of dichloromethane.
  • 61
    • 75749155991 scopus 로고    scopus 로고
    • In addition, a 2D NOESY spectrum of (S, M)-7 was recorded, which can be found in the Supporting Information
    • In addition, a 2D NOESY spectrum of (S)-(M)-7 was recorded, which can be found in the Supporting Information.
  • 65
    • 70350135455 scopus 로고    scopus 로고
    • For a recent extensive analysis of unidirectionality, competing processes, and efficiency of rotary motors, see
    • For a recent extensive analysis of unidirectionality, competing processes, and efficiency of rotary motors, see: Geertsema, E. M.; van der Molen, S. J.; Martens, M.; Feringa, B. L. Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 16919-16924.
    • (2009) Proc. Natl. Acad. Sci. U.S.A , vol.106 , pp. 16919-16924
    • Geertsema, E.M.1    van der Molen, S.J.2    Martens, M.3    Feringa, B.L.4
  • 66
    • 75749121191 scopus 로고    scopus 로고
    • 1H NMR spectra can be found in the Supporting Information.
    • 1H NMR spectra can be found in the Supporting Information.
  • 67
    • 75749096416 scopus 로고    scopus 로고
    • 1H NMR, that prolonged concentrating in vacuo at this temperature would lead to partial deprotection of the hydrazone; however, this partial deprotection did not result in lower ee's or yields.
    • 1H NMR, that prolonged concentrating in vacuo at this temperature would lead to partial deprotection of the hydrazone; however, this partial deprotection did not result in lower ee's or yields.


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