[CH2:1]([O:4][Si:5]([C:8]([CH3:11])([CH3:10])[CH3:9])([CH3:7])[CH3:6])[C:2]#[CH:3].CC[Mg+].[Br-].N#N.[C:18](=[O:20])=[O:19]>C1COCC1>[Si:5]([O:4][CH2:1][C:2]#[C:3][C:18]([OH:20])=[O:19])([C:8]([CH3:11])([CH3:10])[CH3:9])([CH3:6])[CH3:7]To an ice-cold solution of 13.71 g t-butyldimethylsilyl propargyl ether in 160 mL anhydrous THF was added dropwise 35 mL EtMgBr (3M in Et2O) in a N2 atmosphere. After completing the addition, the reaction was stirred 45 minutes at room temperature. Pellets of dry ice were then added slowly until the reaction became cold and carboxylate salt precipitated. Stirring at room temperature was continued overnight. The reaction was concentrated to dryness and the residue partitioned between H2O and Et2O and the organic extract discarded. The aqueous solution was acidified to pH 2 with 6N HCl and immediately extracted with EtOAc. The organic layer was washed with 10% NaHCO3, H2O, and brine and dried (MgSO4). Filtration and concentration provided 13.56 g of product which was used without purification. 1H-NMR (CDCl3) δ 10.6 (s, 1H), 4.3 (s, 2H), 0.80 (s, 9H), 0.03 (s, 6H). ##STR73##
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