Chlorotrimethylsilane → HCID 14715012, compound

Participants

Reaction Steps

Triethylamine (28 mL, 0.20 mol) and chlorotrimethylsilane (13 mL, 0.10 mol) were successively added to a stirred solution of 3,4-diisopropoxy-2-hydroxy-2-methylcyclobut-3-ene-1-one (14.3 g, 0.0667 mol) in diethyl ether (250 mL). The mixture was allowed to stir at ambient temperatures for 18 hrs. The mixture was filtered through SiO2 contained in a sintered glass funnel. The filter cake was washed with additional diethyl ether. The ether was removed to leave 3,4-diisopropoxy-2-trimethylsilyloxy-2-methylcyclobut-3-ene-1-one (18 g, 94% yield) as a clear oil. Trimethylsilyl trifluoromethanesulfonate (150 μL, 0.78 mmol) was added to a stirred solution of the silyl ether (18 g, 0.0628 mol) and 1,2-bis(trimethylsilyloxy)ethane (16.2 mL, 0.066 mmol) in tetrahydrofuran (36 mL). The solution was stirred for 1 hr at 22° C. and additional trimethylsilyl trifluoromethanesulfonate (150 μL) was then added. The solution was stirred for an additional 0.25 hr and was concentrated to dryness. The residue was flash chromatographed on SiO2 (200 g) with diethyl ether-hexanes (1:1) to afford 2,2-ethylenedioxy-3-isopropoxy-4-methylcyclobut-3-ene-1-one (9 g, 73% yield) as a colorless crystalline solid. A solution of n-Bu4N+CN- (140 mg, 0.52 mmol) in tetrahydrofuran (4 mL) was added dropwise to a stirred solution of the ketal (2.0 g, 0.010 mol) and n-Bu3SnSi(CH3)3 (4.03 g, 0.011 mol) in tetrahydrofuran (60 mL) at 22° C. Stirring was continued for 0.66 hr, and the dark solution was concentrated to dryness. The residue was flash chromatographed on SiO2 (80 g) with hexane and then with diethyl ether-hexane (25:75) to afford the title compound as a yellow oil (4.11 g, 95% yield).

Provenance & Evidence