Into a 1000 mL three-neck flask equipped with magnetic stirrer, pressure-equalizing addition funnel and nitrogen line was charged with 200 mL of anhydrous THF. Ttitanium tetrachloride (17 mL) was added dropwise over a period of 30 minutes. The suspension was stirred for 20 minutes and 25.5 parts of zinc was added in small portions . The reaction mixture was heated under reflux for 2 hours and 42.5 mL of triethylamine was added dropwise. After refluxing one hour, 9 parts of a solution of methyl 3-tert-butyldimethylsiloxybenzoate and 4 parts of ketone (77) in 100 mL of dry THF was added over a period of 60 minutes and the reaction mixture was heated for one hour. The mixture on TLC silica gel plate showed the presence of the starting ester. An additional 1 part of starting ketone (77) in 35 mL of dry THF was added dropwise over 45 minutes and refluxed for two hours. The mixture was cooled to room temperature, diluted with 600 mL of hexane and decanted. The residue was washed with 3×250 mL of hexane. The combined hexane layer was filtered and evaporated under reduced pressure to give an oily material which was purified by chromatography on silica gel column using 5% ethyl acetate/hexane as an eluant. The fractions were checked by TLC on silica gel plate and the desired fractions were combined. The solvent was evaporated under reduced pressure to give an oil, yield 9.6 parts.
