ethyl (2S)-2-hydroxy-2-phenylacetate

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

Procedure: Ethyl phenylglyoxylate acid (0.5 g) was asymmetrically reduced in the same manner as in Example 19, except that 1.33 g (11.2 mmol) of succinic acid was used in place of benzoic acid, giving 0.44 g of ethyl (S)-(+)-2-hydroxy-2-phenylacetate, having a specific rotation [α]D18 of +19.4° (cl. 18, CHCl3). The synthesis yield was 87% and the optical yield was 15% e.e. (see Reference 7).

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

Procedure: A dispersion of 0.43 g (11.3 mmol) of sodium borohydride in THF (20 ml) was cooled in a cryostat at -20° C., 1.38 g (11.3 mmol) of benzoic acid was added with stirring, and the mixture was stirred for two to three minutes. A solution of diethyl L-(+)-tartrate in THF (10 ml) was then added, the mixture was stirred for five minutes, a solution of 5 g (2.8 mmol) of ethyl phenyl-glyoxylate in THF (2 ml) was further added over a period of one to two minutes, and stirring was continued for one hour. The reaction mixgture was treated in the same manner as described in Example 1, giving 0.43 g of ethyl (S)-(+)-2-hydroxy-2-phenylacetate, having specific rotation [α]D18 of +17.6° (cl. 18, CHCl3). The synthesis yield was 85% and the optical yield was 15% e.e. (see Reference 7). the mixture was stirred for two to three minutes the mixture was stirred for five minutes stirring The reaction mixgture was treated in the same manner

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

Procedure: Following a procedure similar to that described in Preparation 23, but using 23.8 g of ethyl (S)-(+)-mandelate, 26.6 g of imidazole, 400 ml of dimethylformamide, 30.1 g of t-butyldimethylsilyl chloride and 100 ml of dimethylformamide, the title compound was obtained as a liquid, boiling at 125.5°/3.0 mmHg (400 Pa). that described in Preparation 23

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 31.4 g of t-butyldimethylsilyl chloride in 200 ml of dimethylformamide was added dropwise to a solution of 25 g of ethyl (S)-(+)-mandelate and 28.4 g of imidazole in 800 ml of dimethylformamide, and the resulting mixture was stirred overnight at 40° C. At the end of this time, the dimethylformamide solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 10:1 by volume mixture of hexane and ethyl acetate as the eluent, to give the title compound having an Rf=0.84 (thin layer chromatography over silica gel, using a 10:1 by volume mixture of hexane and ethyl acetate as the developing solvent). At the end of this time, the dimethylformamide solvent was removed by distillation under reduced pressure the resulting residue was purified by column chromatography through silica gel by volume mixture of hexane and ethyl acetate as the eluent

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

Procedure: Following a procedure similar to that described in Preparation 23, but using 23.8 g of ethyl (S)-(+)-mandelate, 26.6 g of imidazole, 400 ml of dimethylformamide, 30.1 g of t-butyldimethylsilyl chloride and 100 ml of dimethylformamide, the title compound was obtained as a liquid, boiling at 125.5°/3.0 mmHg (400 Pa). [α]D23 +40.9° (c=1.02, chloroform). that described in Preparation 23

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 31.4 g of t-butyldimethylsilyl chloride in 200 ml of dimethylformamide was added dropwise to a solution of 25 g of ethyl (S)-(+)-mandelate and 28.4 g of imidazole in 800 ml of dimethylformamide, and the resulting mixture was stirred overnight at 40° C. At the end of this time, the dimethylformamide solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 10:1 by volume mixture of hexane and ethyl acetate as the eluent, to give the title compound having an Rf=0.84 (thin layer chromatography over silica gel, using a 10: 1by volume mixture of hexane and ethyl acetate as the developing solvent). At the end of this time, the dimethylformamide solvent was removed by distillation under reduced pressure the resulting residue was purified by column chromatography through silica gel by volume mixture of hexane and ethyl acetate as the eluent