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Synlett
Volumn , Issue 16, 2008, Pages 2471-2474
Direct asymmetric aldol reaction catalyzed by an imidazolium-tagged trans-4-hydroxy-l-proline under aqueous biphasic conditions
Author keywords

Aldol reactions; Asymmetric organocatalysis; Biphasic aqueous catalysis; Catalyst recycling; Ionic tagged proline
Indexed keywords

IMIDAZOLE DERIVATIVE; PROLINE DERIVATIVE;
EID: 54149117629     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2008-1078055     Document Type: Article
Times cited : (57)
References (38)
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    • List, B.; Lerner, R. A.; Barbas, C. F. III J. Am. Chem. Soc. 2000, 122, 2395.
    • (e) List, B.; Lerner, R. A.; Barbas, C. F. III J. Am. Chem. Soc. 2000, 122, 2395.
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    • 34250726521 scopus 로고    scopus 로고
    • For a recent debate on the role of water in organocatalytic reactions, see: a
    • For a recent debate on the role of water in organocatalytic reactions, see: (a) Blackmond, D. G.; Armstrong, A.; Coombe, V.; Wells, A. Angew. Chem. Int. Ed. 2007, 46, 3798.
    • (2007) Angew. Chem. Int. Ed , vol.46 , pp. 3798
    • Blackmond, D.G.1    Armstrong, A.2    Coombe, V.3    Wells, A.4
  • 11
    • 31444456557 scopus 로고    scopus 로고
    • Mase, N.; Nakai, Y.; Ohara, N.; Yoda, H.; Takabe, K.; Tanaka, F.; Barbas, C. F. III J. Am. Chem. Soc. 2006, 128, 734.
    • (b) Mase, N.; Nakai, Y.; Ohara, N.; Yoda, H.; Takabe, K.; Tanaka, F.; Barbas, C. F. III J. Am. Chem. Soc. 2006, 128, 734.
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    • 24044470646 scopus 로고    scopus 로고
    • (a) Li, C.-J. Chem. Rev. 2005, 105, 3095.
    • (2005) Chem. Rev , vol.105 , pp. 3095
    • Li, C.-J.1
  • 31
  • 36
    • 54149115050 scopus 로고    scopus 로고
    • General Procedure for Cross-Aldol Condensation of Aromatic Aldehydes (Table 1, entry 1) Catalyst 1b (13.4 mg, 0.025 mmol) was stirred in H2O (0.8 mL) until a clear solution was obtained. Cyclohexanone (0.259 mL, 2.5 mmol) was added and the mixture was stirred for 20 min whereupon the reaction mixture became an emulsion. 4-Nitrobenzaldehyde (75.5 mg, 0.5 mmol) was then added, and the reaction mixture was allowed to stir for a further 24 h at 25°C. Cyclohexanone and water were removed under reduced pressure and the residue was extracted with Et2O (4 x 3 mL, The combined organic extracts were dried over Na2SO4, concentrated in vacuo, and purified by silica gel column chromatography (cyclohexane-EtOAc, 7:3) to obtain the pure anti-aldol adduct in 93% yield and the syn-adduct in 4
    • 4, concentrated in vacuo, and purified by silica gel column chromatography (cyclohexane-EtOAc, 7:3) to obtain the pure anti-aldol adduct in 93% yield and the syn-adduct in 4%.
  • 37
    • 54149095532 scopus 로고    scopus 로고
    • 2O was added (0.012 mL), and the solution was stirred for 10 min before the addition of isobutyraldehyde (0.046 mL, 0.5 mmol). The reaction mixture was allowed to stir for a further 72 h at 25°C. Cyclohexanone and water were removed under reduced pressure and the residue was purified by silica gel column chromatography (cyclohexane-EtOAc, 9:1) to afford the pure anti-aldol adduct in 60% yield.
    • 2O was added (0.012 mL), and the solution was stirred for 10 min before the addition of isobutyraldehyde (0.046 mL, 0.5 mmol). The reaction mixture was allowed to stir for a further 72 h at 25°C. Cyclohexanone and water were removed under reduced pressure and the residue was purified by silica gel column chromatography (cyclohexane-EtOAc, 9:1) to afford the pure anti-aldol adduct in 60% yield.
  • 38
    • 54149119496 scopus 로고    scopus 로고
    • 2O and the starting substrates.
    • 2O and the starting substrates.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.