(z)-7-{(1r,2s)-2-[(e)-(s)-5-(4-Bromo-5-methyl-thiophen-2-yl)-3-(tert-butyl-dimethyl-silanyloxy)-pent-1-enyl]-5-oxo-cyclopent-3-enyl}-hept-5-enoic acid methyl ester → (z)-7-{(1r,2s)-2-[(e)-(s)-5-(4-Bromo-5-methyl-thiophen-2-yl)-3-(tert-butyl-dimethyl-silanyloxy)-pent-1-enyl]-5-oxo-3-vinyl-cyclopentyl}-hept-5-enoic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

Vinylmagnesium bromide (1.25 mL, 1.25 mmol, 1 M/THF) was added to a 0° C. mixture of CuI (158 mg, 0.83 mmol) in 2 mL THF. The dark mixture was stirred for 5 min. and then was cooled to −78° C. A solution of Enone 7 (169 mg, 0.28 mmol) in 1 mL THF was added by cannula, rinsing with 0.25 mL THF. The mixture was stirred for 1.5 h and then 20 mL saturated NH4Cl was added. The resulting mixture was stirred for 20 min. and then was extracted with ethyl acetate (3×20 mL). The combined ethyl acetate solution was dried (Na2SO4), filtered and evaporated. Purification by flash chromatography on silica gel (7.5% ethyl acetate/hexanes) gave the title ketone (138 mg, 0.22 mmol, 79%).

Provenance & Evidence