Dibromomethane → HCID 57857071, compound

Participants

Reaction Conditions

Reaction Steps

(Z)-Methyl 7-((1R,2R,5S)-2-((R,E)-3-(benzo[b]thiophen-2-yl)-3-(tert-butyldiphenylsilyloxy)prop-1-enyl)-3-oxo-5-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoate (15a, limiting reagent) is dissolved in DCM (0.05 M) under a nitrogen atmosphere and cooled to 0° C. A solution consisting of zinc methylene dibromide titanium tetrachloride is prepared by combining zinc dust (2.3 g) in THF (40 mL) with methylene dibromide (0.81 mL) at −40° C. under a nitrogen atmosphere. To the suspension is slowly added TiCl4 (0.92 mL). Portions (2 mL) of the zinc methylene dibromide titanium tetrachloride solution are added until the reaction is complete as judged by TLC. Upon completion, the reaction mixture is diluted with ethyl acetate and filtered twice through a bed of Celite. The filtrate is washed with a saturated aqueous solution of sodium bicarbonate, then with a 50% aqueous solution of brine. The organic phase is dried over sodium sulfate, filtered, and the solvent is evaporated. The crude product is purified by flash chromatography on regular silica gel eluted with hexanes-ethyl acetate to afford the title intermediate 17a.

Provenance & Evidence