Hydrochloric Acid → HCID 25130203, compound

Participants

Reaction Conditions

Reaction Steps

A solution of Et2AlCl (1.8 M in toluene, 158 mL, 284 mmol) was added slowly down the flask wall to a −78° C. solution of (4R)-4-benzyl-3-[(2E)-4-(benzyloxy)but-2-enoyl]-1,3-oxazolidin-2-one (70.9 g, 202 mmol) in CH2Cl2 (200 mL). After 10 min, a solution of 2-(trimethylsilyl)oxy-1,3,-butadiene (100 g, 700 mmol) in CH2Cl2 (120 mL) was introduced in the same manner over a period of 15 min. Stirring was continued at −78° C. overnight (18 h). The reaction flask contents were then warmed to −50° C. and a solution composed of THF (150 mL) and 6M HCl (150 mL) was CAREFULLY added dropwise over 45 min followed by stirring at rt for 1 h. Water, ethyl acetate and Celite® were then added and the mixture was filtered through a Celite® pad. The filtrate was transferred to a separatory funnel and the layers were separated. The organic phase was washed with saturated NaCl aqueous solution, dried over a mixture of Na2SO4 and MgSO4 and concentrated in vacuo. Flash chromatography of the residue on silica gel eluting with 13/87 ethyl acetate/benzene gave (4R)-4-benzyl-3-({(1R,2R)-2-[(benzyloxy)methyl]-4-oxocyclohexyl}carbonyl)-1,3-oxazolidin-2-one as a colorless solid. 1H NMR (400 MHz, d6-acetone) δ 7.38-7.32 (6H, m), 7.31-7.25 (4H, m), 4.59-4.53 (1H, m), 4.47 (2H, q, J= 8.5 Hz), 4.19 (1H, dd, J= 3.0, 9.0 Hz), 4.15-4.09 (1H, m), 4.03 (1H, t, J= 8.6 Hz), 3.53-3.47 (2H, m), 3.13 (1H, dd, J= 3.4, 13.6 Hz), 2.97 (1H, dd, J= 8.2, 13.5 Hz), 2.70-2.60 (1H, m), 2.54-2.46 (1H, m), 2.44 (2H, d, J= 9.3 Hz), 2.41-2.29 (2H, m), 1.92-1.82 (1H, m).

Provenance & Evidence