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Synlett
Volumn , Issue 11, 2007, Pages 1683-1686
The catalytic asymmetric claisen rearrangement (CAC) in natural product synthesis: Synthetic studies toward (-)-ecklonialactone B
Author keywords

Asymmetric catalysis; Lewis acids; Natural products; Pericyclic reactions; Total synthesis
Indexed keywords

ECKLONIALACTONE B; ETHER; NATURAL PRODUCT; UNCLASSIFIED DRUG;
EID: 34447506576     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2007-982563     Document Type: Article
Times cited : (18)
References (38)
  • 3
    • 0000137805 scopus 로고
    • For a review on oxylipins, see
    • For a review on oxylipins, see: Gerwick, W. H. Chem. Rev. 1993, 93, 1807.
    • (1993) Chem. Rev , vol.93 , pp. 1807
    • Gerwick, W.H.1
  • 5
    • 0142250008 scopus 로고    scopus 로고
    • Ecklonialactones have also been isolated from the brown a\ga Eisenia bicyclis, see: Kousaka, K.; Ogi, N.; Akazawa, Y.; Fujieda, M.; Yamamoto, Y.; Takada, Y.; Kimura, J. J. Nat. Prod. 2003, 66, 1318.
    • Ecklonialactones have also been isolated from the brown a\ga Eisenia bicyclis, see: Kousaka, K.; Ogi, N.; Akazawa, Y.; Fujieda, M.; Yamamoto, Y.; Takada, Y.; Kimura, J. J. Nat. Prod. 2003, 66, 1318.
  • 12
    • 34447536883 scopus 로고
    • 434; our experiments, it was beneficial to replace the originally used solvent 1,4-dioxane by THF
    • (b) Haraguchi, K.; Tanaka, H.; Miyasaka, T. Synthesis 1989, 434; in our experiments, it was beneficial to replace the originally used solvent 1,4-dioxane by THF.
    • (1989) Synthesis
    • Haraguchi, K.1    Tanaka, H.2    Miyasaka, T.3
  • 23
    • 34447550772 scopus 로고    scopus 로고
    • R (Z,Z)-5 = 22 min, baseline separation with 100 mg/injection.
    • R (Z,Z)-5 = 22 min, baseline separation with 100 mg/injection.
  • 24
    • 0033597634 scopus 로고    scopus 로고
    • Though the synthesis of 3-butenal has been reported in the literature, the isomerization to crotonic aldehyde could not be prevented. For the preparation of 3-butenal, see: Crimmins, M. T, Choy, A. L. J. Am. Chem. Soc. 1999, 121, 5653
    • Though the synthesis of 3-butenal has been reported in the literature, the isomerization to crotonic aldehyde could not be prevented. For the preparation of 3-butenal, see: Crimmins, M. T.; Choy, A. L. J. Am. Chem. Soc. 1999, 121, 5653.
  • 26
    • 34447527817 scopus 로고    scopus 로고
    • Synthesis of (3R,4R)-4 A stock solution of {Cu[(S,S)-tert-Bu-box, H2O) 2(SbF6)2 (10) in CF3CH 2OH (1 mL, 0.1 M, 86 mg, 0.1 mmol, 0.05 equiv) was dissolved in CH2Cl2 (5 mL, The allyl vinyl ether (E,Z)-5 (0.59 g, 2.0 mmol, 1 equiv) was then added and the solution was stirred over night at r.t. At this point, additional {Cu[(S,S)-tert-Bu-box, H2O)2(SbF6)2 (0.5 mL, 0.1 M in CF3CH2OH, 43 mg, 0.05 mmol, 0.025 equiv) was added. The reaction mixture was stirred for 3 d at r.t. and then concentrated under reduced pressure. The catalyst was removed by filtering the crude product mixture through a short path silica gel column. Subsequent flash chromatography (hexane-EtOAc, 50:1) afforded the α-keto ester 4 0.54 g, 1.8 mmol, 92, as a light y
    • 3).
  • 31
    • 34447517684 scopus 로고    scopus 로고
    • Synthesis of 3 Diene 11 (36.4 mg, 0.12 mmol, 1 equiv) was dissolved in DCE (2.5 mL) in a septum-sealed round-bottomed flask. The flask was twice evacuated (20 mbar, 2 min) and ventilated with argon. The Grubbs catalyst 12 (1.0 mg, 1.2 μmol, 0.01 equiv) was then added to the solution and the flask was again twice evacuated and ventilated with argon. The reaction mixture was then stirred for 5 h at 40°C. Silica gel (120 mg) was subsequently added and the heterogeneous mixture was stirred for several minutes. The solid was then removed by filtration and the solvents were evaporated at reduced pressure. The crude product was purified by flash chromatography (hexane-EtOAc, 20:1 to 10:1) to afford the cyclopentenoid 3 (27.6 mg, 0.10 mmol, 84, as a light yellow oil. TLC: Rf, 0.17 (hexane-EtOAc, 5:1, 1H NMR (400 MHz, CDCl3, δ, 2.32 ddd, J1, 15.9 Hz, J2, 6.0 Hz, J3
    • 3).
  • 35
    • 34447517683 scopus 로고    scopus 로고
    • Synthesis of 2 To a solution of the olefin 17 (79.6 mg, 0.32 mmol, 1 equiv) in CH2Cl2 (12 mL) was added Na 2HPO4 (137.7 mg, 0.97 mmol, 3 equiv) and MCPBA (77% purity, 108.7 mg, 0.49 mmol, 1.5 equiv) at 0°C. The reaction mixture was then stirred for 7 h at r.t. and subsequently quenched with sat. aq Na 2SO3 solution. The layers were separated and the aq phase was extracted three times with CH2Cl2. The combined organic phases were dried with MgSO4 and concentrated under reduced pressure. Flash chromatography (hexane-EtOAc, 20:1 to 10:1) afforded the epoxide 2 (56 mg, 0.21 mmol, 66, and its diastereomer 18 (22 mg, 0.08 mmol, 26, TLC (hexane-EtOAc, 2:1, Rf(18, 0.41, Rf(2, 0.31. Compound 2: 1H NMR (400 MHz, CDCl3, δ, 0.92 dd, J1, J 2, 7
    • 3).
  • 36
    • 0000458209 scopus 로고    scopus 로고
    • The stereochemical result of the epoxidation may be explained by assuming a favorable hydroxyl directed (12Si,13Si)-attack of the peracid, see: (a) Hoveyda, A. H, Evans, D. A, Fu, G. C. Chem. Rev. 1993, 93, 1307; and literature cited therein
    • The stereochemical result of the epoxidation may be explained by assuming a favorable hydroxyl directed (12Si,13Si)-attack of the peracid, see: (a) Hoveyda, A. H.; Evans, D. A.; Fu, G. C. Chem. Rev. 1993, 93, 1307; and literature cited therein.
  • 37
    • 33748595277 scopus 로고    scopus 로고
    • Alternatively and or additionally, the (12Si, 13Si)- approach of the peracid from the face opposite to the benzyloxymethyl group on C11 should be favorable. For recent peracid epoxidations of highly substituted cyclopentenoids in the context of the total synthesis of oxylipins, see for example: (b) Ghosh, S.; Sinha, S.; Drew, M. G. B. Org. Lett. 2006, 8, 3781.
    • Alternatively and or additionally, the (12Si, 13Si)- approach of the peracid from the face opposite to the benzyloxymethyl group on C11 should be favorable. For recent peracid epoxidations of highly substituted cyclopentenoids in the context of the total synthesis of oxylipins, see for example: (b) Ghosh, S.; Sinha, S.; Drew, M. G. B. Org. Lett. 2006, 8, 3781.

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