HCID 46900993, compound → HCID 46900994, compound

Participants

Reaction Steps

Under an atmosphere of argon, a 1.9 M solution of tert-butyl lithium in pentane (10.0 ml, 19.0 mmol) was added in one portion with stirring at −78° C. to a solution of (E/Z)-1-ethoxyprop-1-ene (1.61 g, 18.7 mmol) in pentane (20 ml). The reaction mixture was then allowed to warm to 0° C. within 30 min. Subsequently, TMEDA (5.39 g, 46.4 mmol) was added, and the reaction mixture was allowed to warm to room temp. After stirring for 1 h at room temp., the mixture was cooled to −78° C. and chloro(dicyclopropyl)-methylsilane (3.00 g, 18.7 mmol, prepared according to Example 1) was added dropwise over a period of 30 min. After a further 16 h stirring at room temp., the mixture was poured into water (50 ml). After 10 min. of stirring, the organic layer was separated, and the aqueous one extracted with Et2O (2×50 ml). The combined organic extracts were dried (Na2SO4), and concentrated under reduced pressure to afford crude dicyclopropyl(1-ethoxypropionyl)methylsilane, which was taken up in acetone/1 N HCl (2:1, 48 ml). The reaction mixture was stirred for 45 min. at room temp. followed by the addition of water/Et2O (1:1, 100 ml). The organic layer was separated, and the aqueous one extracted with Et2O (2×30 ml). The combined ethereal extracts were dried (Na2SO4) and concentrated under reduced pressure. Silica-gel chromatography (silica gel 40-63 μm, hexane/EtOAc, 9:1, relevant fractions were determined by GC) followed by bulb-to-bulb distillation (0.08 mbar, 40° C.) of the resulting residue provided 437 mg (13% over 2 steps) of dicyclopropyl(methyl)propionylsilane. Following the procedure for the preparation of dicyclopropyl(1-hydroxy-1-methylpropyl)methylsilane (see Example 5), dicyclopropyl(methyl)propionylsilane (470 mg, 2.58 mmol) was then reacted with ethyl lithium (1.7 M in n-Bu2O, 12.1 ml, 20.6 mmol) to provide after purification by silica-gel flash chromatography (silica gel 40-63 μm, hexane/EtOAc, 9:1) 360 mg (66%) of the odoriferous title compound.

Provenance & Evidence