1-methoxy-4-trimethylsilylbut-3-yn-2-one

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 52.85 ml of 0.5 M cyclopropylmagnesium bromide (26.43 mmol, Aldrich) are added to a solution of 3 g of 1-methoxy-4-(trimethylsilyl)but-3-yn-2-one (17.62 mmol) in 160 ml of ether. The mixture is stirred at ambient temperature overnight and is then cooled with a water/ice bath and a solution of NH4Claq and ethyl acetate is added. The mixture is extracted 3 times with ethyl acetate and the organic phases are then combined, dried over sodium sulphate, filtered, and concentrated under vacuum. The oily residue is purified by silica column chromatography, elution being carried out with a cyclohexane:ethyl acetate gradient, 100:0 to 80:20, so as to obtain 1.9 g of (±)-2-cyclopropyl-1-methoxy-4-(trimethylsilyl)but-3-yn-2-ol in the form of an oil, with a yield of 51%. is then cooled with a water/ice bath The mixture is extracted 3 times with ethyl acetate dried over sodium sulphate filtered concentrated under vacuum The oily residue is purified by silica column chromatography, elution

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 14.75 ml of trimethylsilylacetylene (103.62 mmol) in 250 ml of tetrahydrofuran is cooled to −70° C. and then 64.76 ml of a 1.6 M solution of n-BuLi (103.62 mmol) in hexane are added. The mixture is stirred for 25 minutes at −70° C. and then a solution of 13.14 g of N-methoxy-N-methyl-2-methoxyacetamide (98.69 mmol) in 250 ml of tetrahydrofuran is added rapidly. During the addition, the temperature rises to −50° C., and then the cold bath is removed and the mixture is stirred for 2 hours at ambient temperature. A 1N solution of HClaq is added and then extraction is carried out 4 times with ethyl acetate. The organic phases are combined, dried over sodium sulphate, filtered, and concentrated under vacuum. 13.4 g of 1-methoxy-4-(trimethylsilyl)but-3-yn-2-one are obtained in the form of a light brown oil which is used without subsequent purification (crude yield=80%). During the addition rises to −50° C. the cold bath is removed the mixture is stirred for 2 hours at ambient temperature A 1N solution of HClaq is added extraction dried over sodium sulphate filtered concentrated under vacuum