tert-butyl 3-oxo-4-phenylmethoxybutanoate

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5,54 ml (40 mmols--2 equivalents) of triethylamine was added dropwise to a solution, cooled to 0° C., of 5,29 g (20 mmols) of tert.-butyl 4-benzyloxyacetoacetate and 4,34 g. (22 mmols) of 4-toluenesulphonyl azide in 40 ml of anhydrons acetonitrile. The mixture was stirred for 30 minutes at 0° C., treated with 8 g of Celite and evaporated in vacuo. Chromatography of the residue on 100 g of silica gel (toluene:ethyl acetate 95:5) yielded 3,98 g of the title compound as colorless crystals, melting point: 68° C., RF : 0,31 (toluene:ethyl acetate 95:5). treated with 8 g of Celite evaporated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 963 mg (5 mmol) of tert.-butyl 4-benzyloxyacetoacetate and 200 mg of palladium (10% on charcoal) in 50 ml of methanol was stirred at room temperature under a hydrogen atmosphere (1 atmosphere) for 1.5 hours. The catalyst was filtered off washed with a little methylene chloride. The filtrate solution was evaporated in vacuo and the residue was filtered through 3 g of neutral aluminum oxide (methylene chloride). The solvent was evaporated off in vacuo and the oil which remained was dried under a high vacuum. 567 mg (65% of tert.-butyl 4-hydroxyacetoacetate were obtained, and were used immediately for further reactions. The catalyst was filtered off washed with a little methylene chloride The filtrate solution was evaporated in vacuo the residue was filtered through 3 g of neutral aluminum oxide (methylene chloride) The solvent was evaporated off in vacuo the oil which remained was dried under a high vacuum

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5.54 ml (40 mmol - 2 equivalents) of triethylamine were added dropwise to a solution, which had been cooled to 0° C., of 5.29 g (20 mmol) of tert.-butyl 4-benzyloxyacetoacetate and 4.34 g (22 mmol) of p-toluenesulphonyl azide in 40 ml of anhydrous acetonitrile. The mixture was stirred at 0° C. for 30 min, 8 g of kieselguhr were added, and evaporation in vacuo and chromatography on 100 g of silica gel (toluene:ethyl acetate 95:5) were carried out. 3.98 g (69%) of the title compound were obtained as colorless crystals, melting point: 68° C., Rf: 0.31 (toluene:ethyl acetate 95:5). 8 g of kieselguhr were added evaporation in vacuo and chromatography on 100 g of silica gel (toluene:ethyl acetate 95:5)