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Volumn 10, Issue 18, 2008, Pages 4085-4088

Enantioselective synthesis utilizing enantiomorphous organic crystal of achiral benzils as a source of chirality in asymmetric autocatalysis

Author keywords

[No Author keywords available]

Indexed keywords

BENZIL; DRUG DERIVATIVE; PHENYLGLYOXAL; PYRIMIDINE; PYRIMIDINE DERIVATIVE;

EID: 55949120492     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol801600y     Document Type: Article
Times cited : (39)

References (68)
  • 18
    • 0012934943 scopus 로고    scopus 로고
    • Pályi, G, Zucchi, C, Caglioti, L, Eds, Elsevier: Paris
    • (c) Soai, K. In Fundamentals of Life; Pályi, G., Zucchi, C., Caglioti, L., Eds.; Elsevier: Paris, 2002; p 427.
    • (2002) Fundamentals of Life , pp. 427
    • Soai, K.1
  • 22
    • 61349131685 scopus 로고    scopus 로고
    • Diaz-Herrera, E, Juaristi, E, Eds, American Institute of Physics: Melville, NY
    • (g) Soai, K.; Kawasaki, T. In Recent Developments in Physical Chemistry; Diaz-Herrera, E., Juaristi, E., Eds.; American Institute of Physics: Melville, NY, 2008; p 68.
    • (2008) Recent Developments in Physical Chemistry , pp. 68
    • Soai, K.1    Kawasaki, T.2
  • 61
    • 61349170962 scopus 로고    scopus 로고
    • Although the possibility of the solid-state stereospecific reaction using the chiral crystal of benzil 1 as a reactant has been envisaged, to the best of our knowledge, there has not been the report of the observation of the asymmetric induction in the solid-state reaction. See also ref 2b and references cited therein
    • Although the possibility of the solid-state stereospecific reaction using the chiral crystal of benzil 1 as a reactant has been envisaged, to the best of our knowledge, there has not been the report of the observation of the asymmetric induction in the solid-state reaction. See also ref 2b and references cited therein.
  • 67
    • 61349122364 scopus 로고    scopus 로고
    • The single crystal with enough size to perform the asymmetric autocatalysis using as the chiral initiator could not be obtained in the present stage. Thus, the powder (particle size: 10-20 μm) of 4,4′- dibromobenzil crystals used as chiral source of asymmetric autocatalysis was prepared by grinding the powder-like crystals of 2, which were grown by a seeding method under stirring conditions using the fragment of native single crystals whose absolute configuration was known by X-ray analysis The details on the preparation of single and powder-like crystals of 2 are presented in the Supporting Information
    • The single crystal with enough size to perform the asymmetric autocatalysis using as the chiral initiator could not be obtained in the present stage. Thus, the powder (particle size: 10-20 μm) of 4,4′- dibromobenzil crystals used as chiral source of asymmetric autocatalysis was prepared by grinding the powder-like crystals of 2, which were grown by a seeding method under stirring conditions using the fragment of native single crystals whose absolute configuration was known by X-ray analysis (The details on the preparation of single and powder-like crystals of 2 are presented in the Supporting Information).
  • 68
    • 61349178262 scopus 로고    scopus 로고
    • General procedure for asymmetric autocatalysis (Table 1, entry 9, An enantiomorphous powder-like crystal of 4,4′-dibromobenzil 2 was ground into a fine powder using a pestle and mortar (particle size: 10-20 μm, i-Pr2Zn (0.03 mmol, 0.3 mL, 1.0 M hexane solution) was added dropwise to a finely powdered crystal of M-2 (55.2 mg, 0.15 mmol) and aldehyde 3 (9.4 mg, 0.05 mmol) over a period of l h at 0 °C. After the mixture was stirred for 12 h, toluene (2.0 mL) and i-Pr2Zn (0.6 mmol, 0.6 mL, 1.0 M toluene solution) were added at 0 °C. Then, a solution of 3 (37.4 mg, 0.2 mmol) in toluene (1.0 mL) was added over a period of l h at 0 °C and the reaction mixture stirred at 0 °C for 2 h. Once again, after toluene (5.0 mL) and (i-Pr2Zn (0.8 mmol, 0.8 mL, 1.0 M toluene solution) were added, a solution of 3 (75.3 mg, 0.4 mmol) in toluene (2.0 mL) was added dropwise over a period of 50 min at 0 °C. After the m
    • 2Zn (0.8 mmol, 0.8 mL, 1.0 M toluene solution) were added, a solution of 3 (75.3 mg, 0.4 mmol) in toluene (2.0 mL) was added dropwise over a period of 50 min at 0 °C. After the mixture was stirred for 2 h, the reaction was quenched with a mixture of 30% aqueous ammonia and saturated aqueous ammonium chloride (2:1, v/v) solution (10 mL). The mixture extracted using ethyl acetate three times. The combined organic layers were dried over anhydrous sodium sulfate and evaporated in vacuo. Purification of the residue by silica gel column chromatography (hexane/ethyl acetate, 3:1 to 2:1, v/v) gave the (R)-alkanol 4 (131.4 mg, 0.566 mmol, 96% ee) in 87% yield.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.