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Synlett
Volumn , Issue 3, 2009, Pages 417-420
Cryptophycin-39 unit a precursor synthesis by a tandem Shi epoxidation and lactonization reaction of trans-styryl acetic acid
Author keywords

Asymmetric synthesis; Bioorganic chemistry; Epoxidations; Lactones; Natural products
Indexed keywords

EID: 62249111433     PISSN: 09365214     EISSN: 14372096     Source Type: Journal    
DOI: 10.1055/s-0028-1087541     Document Type: Article
Times cited : (8)
References (36)
  • 26
    • 62249144747 scopus 로고    scopus 로고
    • Synthesis of (4R,5S)-4-hydroxy-5- phenyl-tetrahydrofuran-2-one (5) trans-Styryl acetic acid (4, 21.8 mmol, 3.54 g) was dissolved in MeCN (210 mL, Aqueous KOH soln (1 M, 21.8 mmol, 21.8 mL, acetate buffer (150 mL, prepared by adding 5.00 mL AcOH to 13.82 g K2CO3 in 1000 mL H2O and pH adjusted to 9.3 by the dropwise addition of concd aq NaOH soln) and n-Bu 4NHSO4 (0.954 mmol, 324 mg) were added. The solution was cooled to 0°C and Shi catalyst (3, 7.16 mmol, 1.85 g) was added. Freshly prepared Oxone (29.90 mmol, 18.36 g) in aq Na2EDTA solution (0.4 mM, 0.0432 mmol, 108 mL) and aq K2CO3 soln (108 mL, prepared by dissolving 32.00 g K2CO3 in 200 mL H 2O) were separately added within 120 min at 0°C. The cooling bath was removed, and the mixture was stirred for 180 min. Aqueous HCl 6 M, 0.36 mol, 6
    • 3: C, 67.41; H, 5.66. Found: C, 67.39; H, 5.67. Further analytical data are in accordance with ref. 7.
  • 27
    • 62249210003 scopus 로고    scopus 로고
    • General Procedure for the Synthesis of Substituted trans-Styryl Acetic Acids (Table 1, Entries 2 and 3) KOt-Bu (13 mmol, 1.469 g) in THF (14 mL) was added to a solution of the substituted benzaldehyde (9 mmol) and (2-carboxyethyl)triphenylphosphonium bromide (6 mmol, 2.494 g) in THF (12 mL) at 0°C over 15 min. After stirring for additional 15 min at 0°C and overnight at r.t, H2O (10 mL) and Et2O (50 mL) were added. The phases were acidified with 6 M aq HCl soln to pH 1 and separated. The aqueous phase was extracted with Et 2O (50 mL, The combined organic phases were extracted with sat. aq NaHCO3 soln (2 x 60 mL, The sat. aq NaHCO3 phases were washed with EtOAc (3 x 90 mL, acidified with concd aq HCl to pH 1 and extracted with Et2O (2 x 75 mL, The organic extracts were washed with H 2O (20 mL) and brine 10 mL, After drying over Na2SO 4 the solve
    • 4 the solvent was removed in vacuo (40°C) yielding the corresponding substituted trans-styryl acetic acid in 70-74% yield.
  • 28
    • 62249141422 scopus 로고    scopus 로고
    • Synthesis of (3R,4R,5 S)-4-Hydroxy-3-methyl-5-phenyl-tetrahydrofuran-2-one (6) Diisopropylamine (11.56 mmol, 1.6 mL) in THF (28 mL) was cooled to -78°C, then n-BuLi (1.6 M in hexane, 11.49 mmol, 7.2 mL) was added dropwise over 15 min. The solution was stirred for 15 min at -78°C and for 30 min at r.t. The LDA solution was cooled to -78°C again and DMPU (34.87 mmol, 4.2 mL) was added. After 45 min lactone (5, 4.60 mmol, 819 mg) in THF (19.2 mL) was added during 90 min. After stirring for 45 min and addition of THF (16 mL, MeI (46.6 mmol, 2.9 mL) in THF (8.6 mL) was added during 150 min. The solution was stirred overnight at -78°C. Acetic acid (0.6 mL) in THF (1.0 mL) was added, and the suspension was warmed to r.t. Then, 5% aq Na2SO 3 soln (8.8 mL) was added, and after 5 min the solvent was removed in vacuo 40°C, until a pink suspension remained, which was partitioned betwee
    • 3: C, 68.74; H, 6.29. Found: C, 68.67; H, 6.24.
  • 34
    • 62249173391 scopus 로고    scopus 로고
    • Synthesis of (5S,6S,E)-tert-Butyl-6, 4R,5S)-2,2-dimethyl-5-phenyl-1, 3-dioxolan-4-yl]-5-hydroxyhept-2-enoate (10) Homoallyl alcohol 9 (0.615 mmol, 170 mg) in CH2Cl2 (0.85 mL) was added to a solution of Grubbs II catalyst (0.026 mmol, 22.1 mg) and tert-butylacrylate (0.513 mmol, 74.4 μL) in CH2Cl2 (3.4 mL, The solution was refluxed in the dark overnight. The solvent was removed in vacuo (30°C, and the residue was purified by flash chromatography (hexane-EtOAc, 8:2) yielding 10 (0.369 mmol, 138.8 mg, 72, as a colorless oil; [α]D24 -7.50 (c 1.10, CHClD, 1H NMR (500 MHz, CDCl3, δ, 7.28-7.40 (m, 5 H, 6.77 (m, 1 H, 5.80 (d, J, 15.7 Hz, 1 H, 5.38 (d, J, 7.5 Hz, 1 H, 4.70 (dd, J, 3.8, 7.5 Hz, 1 H, 3.50 (m, 1 H, 2.37 m, 1 H, 2
    • +]: 399.21420; found: 399.21373.
  • 35
    • 62249149179 scopus 로고    scopus 로고
    • Synthesis of (1S,2R,3 S,4S)-3-Methyl-1-phenylhept-6-ene-1,2,4-triol (11) A 5% aq HCl soln (4 mL) was added to a solution of homoallyl alcohol 9 (0.615 mmol, 170.0 mg) in MeOH (6 mL, After refluxing the solution for 90 min MeOH was removed in vacuo (40°C, and the aqueous phase was extracted with Et2O (5 x 30 mL, dried over MgSO4, and purified by flash chromatography (hexane-EtOAc, 7:3, A colorless crystalline solid (11, 0.405 mmol, 95.7 mg, 66, was obtained; [α] D24 43.59 (c 1.22, CHCl3, mp 77°C. 1H NMR (500 MHz, CDCl3, δ, 7.26-7.49 (m, 5 H, 5.80 (m, 1 H, 5.13-5.20 (m, 2 H, 4.70 (δ, J, 7.5 Hz, 1 H, 4.15 (d, J, 7.5 Hz, 1 H, 3.70 (m, 1 H, 2.60 (d, J, 2.5 Hz, 1 H, 2.27-2.44 (m, 3 H, 2.21 (s, 1 H, 1.98 (m, 1 H, 1.16 d, J, 6.9 Hz, 3 H, 13
    • 3: C, 71.16; H, 8.53. Found: C, 71.00; H, 8.60.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.