[CH3:1][Si:2]([C:5]#[CH:6])([CH3:4])[CH3:3].[Li]CCCC.CON(C)[C:15](=[O:19])[CH2:16][O:17][CH3:18]>O1CCCC1.CCCCCC>[CH3:18][O:17][CH2:16][C:15](=[O:19])[C:6]#[C:5][Si:2]([CH3:4])([CH3:3])[CH3:1]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%).
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