Reaktion #61200
ord-941e3bd9796745f6b89c42bd52c56fa5
Reaktionsgleichung
Edukte
Lösungsmittel
Reaktionsbedingungen
Aufarbeitung
- 1Sonstigescrew-cap
- 2Temperaturto cool to room temperature
- 3TemperaturThe reaction was heated at 100° C. overnight
- 4ExtraktionThe resulting mixture was extracted with dichloromethane (3×40 mL)
- 5Trocknenthe combined dichloromethane solution was dried (Na2SO4)
- 6Filtrationfiltered
- 7Sonstigeevaporated
- 8SonstigePurification by flash chromatography on silica gel (30% ethyl acetate/hexanes)
Vorschrift
The procedure described in Reich, S. H. et. al. J. Med. Chem. 2000, 43, 1670 was followed. Pd(OAc)2 (8.2 mg, 0.037 mmol) and triethylamine (0.360 mL, 2.58 mmol) were added to a solution of 3-iodobenzyl alcohol 2-1 (0.27 mL, 2.13 mmol) and methyl acrylate 2-2 (0.220 mL, 2.44 mmol) in CH3CN (4.5 mL). The reaction vessel was sealed with a Teflon screw-cap and was heated at 100° C. for 5 h. At this time, the reaction was allowed to cool to room temperature and the tube was charged with 0.22 mL more of methyl acrylate, 11.7 mg Pd(OAc)2 and 0.360 mL triethylamine. The reaction was heated at 100° C. overnight and then 10 mL saturated ammonium chloride solution was added. The resulting mixture was extracted with dichloromethane (3×40 mL) and the combined dichloromethane solution was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (30% ethyl acetate/hexanes) gave 395 mg (97%) of 2-3. 3-(3-Hydroxymethyl-phenyl)-propionic acid methyl ester (2-4). (Ph3P)3RhCl (11.5 mg, 0.012 mmol) was added to a solution of 2-3 (25 mg, 0.13 mmol) in 0.400 mL ethanol. The reaction was stirred under 1 atm H2 balloon for 20 h and then was filtered through Celite. Evaporation to dryness and purification by flash chromatography on silica gel (30% ethyl acetate/hexanes) gave 2-4 (21 mg, 82%). 3-(3-Iodomethyl-phenyl)-propionic acid methyl ester (2-5). A mixture of Ph3P (36 mg, 0.14 mmol), I2 (41 mg, 0.16 mmol) and imidazole (10.5 mg, 0.15 mmol) in 0.40 mL 1,2-dichloroethane was stirred for 15 min. and then a solution of 2-4 (20.5 mg, 0.11 mmol) in 0.1 mL 1,2-dichloroethane was added by cannula. The resulting mixture was stirred for 1 h and then was filtered through basic alumina, washing with ethyl acetate. The filtrate was evaporated and the residue was purified by flash chromatography on silica gel to give 2-5 (26 mg, 81%). 3-[3-((1R,2S,3R)-3-(tert-Butyl-dimethyl-silanyloxy)-2-{4-[1-(tert-butyl-dimethyl-silanyloxy)-hexyl]-phenyl}-5-oxo-cyclopentylmethyl)-phenyl]-propionic acid methyl ester (3-1). A −78° C. solution of aryl bromide 1-5 (759 mg, 2.0 mmol) in THF (3 mL) was treated with tert-butyllithium (2.6 mL, 4.4 mmol, 1.7 M/pentane). After 30 min., Me2Zn (1.1 mL, 2.2 mmol, 2 M/toluene) was added and the resulting solution was stirred for 15 min. at 0° C. and then was recooled to −78° C. A solution of enone 1-1 (319 mg, 1.5 mmol, Evotec OAI, 151 Milton Park, Abington, Oxon, OX 14 4SD, UK) in 1.7 mL THF was added by syringe pump over 1 h. The resulting mixture was stirred at −78° C. for 2 h, and then HMPA (2.2 mL, 12.6 mmol) was added followed by a solution of 2-5 (2.641 g, 8.7 mmol) in THF (1.6 mL). The reaction was stirred overnight at −40° C. and then was quenched by addition of 40 mL saturated ammonium chloride solution. A little water was added to dissolve the solids and the resulting mixture was extracted with ethyl acetate (3×30 mL). The combined ethyl acetate solution was dried (MgSO4), filtered and evaporated. Purification by flash chromatography on silica gel (10% ethyl acetate/hexanes) gave the title ketone contaminated with ca. 35% of benzyl iodide 2-5 (438 mg).