tert-butyl (3S)-3-hydroxybutanoate

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

Procedure: To a solution of 3.84 g of tert-butyl (S)-3-hydroxybutyrate and 5.86 g of 4-dimethylaminopyridine in 20 ml of methylene chloride was added at 0° C. within 20 minutes a solution of 6.47 g of p-nitrobenzyl chloroformate in 20 ml of methylene chloride. The mixture was stirred for 3 hours at 0° C., then diluted with 50 ml of methylene chloride and washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution, and with brine. The organic layer was dried over sodium sulfate, and the solvent was evaporated in vacuo. The residual oil was chromatographed on silica gel using ethyl acetate/hexane (1:1, v/v) as eluent to yield 5.10 g of tert-butyl (S)-3-(4-nitrobenzyloxycarbonyloxy)-butyrate as a colourless oil. washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution The organic layer was dried over sodium sulfate the solvent was evaporated in vacuo The residual oil was chromatographed on silica gel

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

Procedure: To a solution of 3.84 g of tert-butyl (S)-3-hydroxybutyrate and 5.86 g of 4-dimethylaminopyridine in 20 ml of methylene chloride was added at 0° C. within 20 minutes a solution of 6.47 g of p-nitrobenzyl chloroformate in 20 ml of methylene chloride. The mixture was stirred for 3 hours at 0° C., then diluted with 50 ml of methylene chloride and washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution, and with brine. The organic layer was dried over sodium sulfate, and the solvent was evaporated in vacuo. The residual oil was chromatographed on silica gel using ethyl acetate/hexane (1:1, v/v) as eluent to yield 5.10 g of tert-butyl (S)-3-(4-nitrobenzyloxycarbonyloxy)-butyrate as a colourless oil. washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution The organic layer was dried over sodium sulfate the solvent was evaporated in vacuo The residual oil was chromatographed on silica gel

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

Procedure: To a solution of 3.84 g of tert-butyl (S)-3-hydroxybutyrate and 5.86 g of 4-dimethylaminopyridine in 20 ml of methylene chloride was added at 0° C. within 20 minutes a solution of 6.47 g of p-nitrobenzyl chloroformate in 20 ml of methylene chloride. The mixture was stirred for 3 hours at 0° C., then diluted with 50 ml of methylene chloride and washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution, and with brine. The organic layer was dried over sodium sulfate, and the solvent was evaporated in vacuo. The residual oil was chromatographed on silica gel using ethyl acetate/hexane (1:1, v/v) as eluent to yield 5.10 g of tert-butyl (S)-3-(4-nitrobenzyloxycarbonyloxy)-butyrate as a colourless oil. washed successively with 1N hydrochloric acid, saturated sodium bicarbonate solution The organic layer was dried over sodium sulfate the solvent was evaporated in vacuo The residual oil was chromatographed on silica gel