Triethylborane → HCID 18955973, compound

Participants

Reaction Conditions

Reaction Steps

A 2 liter, 3-necked round bottom flask fitted with 2 dropping funnels was charged with 200 ml THF and cooled to -78° C. under N2. One dropping funnel was charged with a solution of 6.33 g (15.3 mM]t-butyl 3-acetyloxymethyl-7-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate in 300 ml THF. The other funnel was charged with 32 ml 1M-triethylborane in THF, 1.2 ml H20, and 300 ml THF. The funnels were adjusted so their contents were added to the flask at 2.5 ml/min and the temperature of the reaction mixture maintained at -78° . After the addition, the cooling bath was removed and the reaction mixture allowed to warm. When the temperature reached -45° C., 6.67 ml 30% H2O2 was added. At -15°, the reaction mixture was washed with 300 ml brine, the organic layer diluted with 300 ml CH2Cl2, washed with 300 ml brine, dried over MgSO4, filtered and stripped to give 7.46 g of yellow oil which was chromatographed on a flash column with CHCl3 /EtOAc (25:1) to yield 1.289 g (19%) t-butyl-3-acetyl-oxymethyl-7α-ethyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate a 4:1 mixture of the α and β isomers NMR(CDCl3): δ 1.08, t (J™8Hz), 3H; 1.50, s, 9H; 1.8, br, qt, 2H; 2.05, s, 3H; 3.1, brm, 1H; 3.4, d, 2H; 4.35, d (J=2Hz), 1H; 4.82, AB qt (J=12, 6Hz) 2H.

Provenance & Evidence