Diethyl Ether → t-Butyldimethylsilyloxybicyclo[2,2,1]heptan-2-one

Participants

Reaction Steps

3-t-Butyldimethylsilyloxy-1-iodo-1-octene (6.07 g) in dry light petroleum (b.p. 60°-80°, 50 ml) was cooled, under nitrogen, to -70°, 2.1 M n-butyllithium in hexane solution (8.0 ml) was added and the solution was stirred 1/2 hour at -70°. A solution of cuprous n-propyl acetylide (2.15 g) in ether (25 ml) and hexamethylphosphorus triamide (6.04 ml) was added to this solution which was stirred for a further 15 minutes at -70°. 3-endo-t-Butyldimethylsilyloxytricyclo[3,2,0,02,7 ]heptan-6-one (3.7 g) in dry ether (ca. 50 ml) was then added to the orange solution which was stored at -70° for 11/2 hours, and warmed to -30°. The cold reaction mixture was poured into saturated ammonium chloride solution (40 ml) and shaken. The organic layer was removed and the aqueous layer was extracted once with ether (20 ml). The combined organic solutions were then shaken with ice-cold 2% sulphuric acid (ca. 200 ml) and the mixture filtered through hyflo to remove precipitated copper salts. The organic layer was removed, washed once with 8% sodium bicarbonate solution and dried (MgSO4). Evaporation of the solvent gave an oil which was chromatographed on silica in light petroleum containing increasing amounts of ethyl acetate. Light petroleum eluted unreacted octene side chain and impure product was eluted with ethyl acetate/ light petroleum (5:95) as a pale yellow oil (5.26 g). Short path distillation afforded pure title compound as a pale yellow oil (3.29 g) b.p. ca. 180°-200°/0.15 mm.

Provenance & Evidence