2-(1-溴丙-2-基)-1,3-二氧戊环

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A mixture of 110 g (0.56 mol) of 2-(1-bromopropan-2-yl)-1,3-dioxolane, 148.5 g (0.56 mol) of triphenylphosphine and 550 ml of anhydrous toluene is heated at reflux under nitrogen for 24 h. The paste-like salt phase is separated and washed with 5×200 ml of anhydrous ethyl ether. After drying under vacuum there are obtained 191 g of [2-(1,3-dioxolan-2-yl)propan-1-yl]triphenylphosphonium bromide (white solid; yield 75%). is heated at reflux under nitrogen for 24 h The paste-like salt phase is separated washed with 5×200 ml of anhydrous ethyl ether After drying under vacuum

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 0.29 ml (3.4 mmol) of 1,2-dibromoethane was added to a suspension of 1.66 g (68.1 mmol) of magnesium in 5 ml of anhydrous tetrahydrofuran under a stream of nitrogen. 9.96 g (51.1 mmol) of 3-bromo-2-methylpropionaldehyde ethylene acetal [prepared as described in step (i) above] were then added dropwise to the resulting mixture, whilst ice-cooling, after which the mixture was stirred for 1 hour. A solution of 6.58 g (34.1 mmol) of N-methoxy-N-methyl-3,4-dimethylbenzamide in 30 ml of tetrahydrofuran was then added dropwise to the mixture, and the resulting mixture was stirred, whilst ice-cooling for 1 hour. A saturated aqueous solution of ammonium chloride was then added to the mixture, and the resulting mixture was extracted twice with ethyl acetate. The organic extracts were combined and washed with a saturated aqueous solution of sodium chloride, after which they were dried over anhydrous magnesium sulfate and concentrated by evaporation under reduced pressure. The residue thus obtained was applied to a silica gel chromatography column and eluted with a 6:1 by volume mixture of hexane and ethyl acetate, to give 3.26 g (yield 39%) of the title compound as a colorless oily substance. cooling the resulting mixture was stirred, whilst ice- cooling for 1 hour the resulting mixture was extracted twice with ethyl acetate washed with a saturated aqueous solution of sodium chloride after which they were dried over anhydrous magnesium sulfate concentrated by evaporation under reduced pressure The residue thus obtained eluted with a 6:1 by volume mixture of hexane and ethyl acetate