methyl (2S)-2-[tert-butyl(dimethyl)silyl]oxypropanoate

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

Procedure: To a solution of 17A (1.33 g, 6.09 mmol) in THF (20 mL) at 0° C., was added lithium borohydride (0.531 g, 24.36 mmol). The resultant suspension was stirred at rt for 7 h. The reaction was cooled to 0° C., then was quenched with sat. NH4Cl (5 mL). The mixture was diluted with H2O and hexanes. The reaction mixture was acidified with 1 N HCl, then was extracted with hexanes (3×). The combined organic phase was washed with brine, dried (Na2SO4), and concentrated. The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes) to give 17B (980 mg, 5.15 mmol, 85% yield) as a colorless oil. MS (ESI) m/z: 191.2 [M+1]+. 1H NMR (400 MHz, chloroform-d) δ ppm 3.87-3.96 (m, J=6.3, 6.3, 6.3, 6.3, 3.6 Hz, 1H) 3.51 (ddd, J=11.0, 7.7, 3.6 Hz, 1 H) 3.37 (ddd, J=11.1, 6.3, 5.1 Hz, 1H) 1.93 (dd, J=7.8, 5.3 Hz, 1H) 1.12 (d, J=6.3 Hz, 3H) 0.90 (s, 9H) 0.09 (s, 6H). was quenched with sat. NH4Cl (5 mL) The mixture was diluted with H2O and hexanes was extracted with hexanes (3×) The combined organic phase was washed with brine dried (Na2SO4) concentrated The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes)

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

Procedure: To a solution of 17A (1.33 g, 6.09 mmol) in THF (20 mL) at 0° C., was added lithium borohydride (0.531 g, 24.36 mmol). The resultant suspension was stirred at rt for 7 h. The reaction was cooled to 0° C., then was quenched with sat. NH4Cl (5 mL). The mixture was diluted with H2O and hexanes. The reaction mixture was acidified with 1 N HCl, then was extracted with hexanes (3×). The combined organic phase was washed with brine, dried (Na2SO4), and concentrated. The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes) to give 17B (980 mg, 5.15 mmol, 85% yield) as a colorless oil. MS (ESI) m/z: 191.2 [M+1]+. 1H NMR (400 MHz, chloroform-d) δ ppm 3.87-3.96 (m, J=6.3, 6.3, 6.3, 6.3, 3.6 Hz, 1H) 3.51 (ddd, J=11.0, 7.7, 3.6 Hz, 1 H) 3.37 (ddd, J=11.1, 6.3, 5.1 Hz, 1H) 1.93 (dd, J=7.8, 5.3 Hz, 1H) 1.12 (d, J=6.3 Hz, 3H) 0.90 (s, 9H) 0.09 (s, 6H). was quenched with sat. NH4Cl (5 mL) The mixture was diluted with H2O and hexanes was extracted with hexanes (3×) The combined organic phase was washed with brine dried (Na2SO4) concentrated The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes)

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

Procedure: To a solution of (S)-methyl 2-hydroxypropanoate (1.00 g, 9.61 mmol) in DMF (10 mL) at rt, were added imidazole (0.981 g, 14.41 mmol) and TBS-Cl (1.737 g, 11.53 mmol). The mixture was stirred at rt for 3 h. The reaction mixture was diluted with hexanes. The organic phase was washed with water (2×) and brine, dried (Na2SO4) and concentrated. The crude product was purified by flash chromatography (0 to 10% ethyl acetate/hexanes) to give 17A (1.73 g, 7.92 mmol, 82% yield) as a colorless oil. 1H NMR (400 MHz, chloroform-d) δ ppm 4.34 (q, J=6.7 Hz, 1H) 3.72 (s, 3H) 1.40 (d, J=6.8 Hz, 3H) 0.90 (s, 8H) 0.09 (d, J=10.8 Hz, 6H). The organic phase was washed with water (2×) and brine dried (Na2SO4) concentrated The crude product was purified by flash chromatography (0 to 10% ethyl acetate/hexanes)

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

Procedure: To a solution of 17A (1.33 g, 6.09 mmol) in THF (20 mL) at 0° C., was added lithium borohydride (0.531 g, 24.36 mmol). The resultant suspension was stirred at rt for 7 h. The reaction was cooled to 0° C., then was quenched with sat. NH4Cl (5 mL). The mixture was diluted with H2O and hexanes. The reaction mixture was acidified with 1 N HCl, then was extracted with hexanes (3×). The combined organic phase was washed with brine, dried (Na2SO4), and concentrated. The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes) to give 17B (980 mg, 5.15 mmol, 85% yield) as a colorless oil. MS (ESI) m/z: 191.2 [M+1]+. 1H NMR (400 MHz, chloroform-d) δ ppm 3.87-3.96 (m, J=6.3, 6.3, 6.3, 6.3, 3.6 Hz, 1H) 3.51 (ddd, J=11.0, 7.7, 3.6 Hz, 1 H) 3.37 (ddd, J=11.1, 6.3, 5.1 Hz, 1H) 1.93 (dd, J=7.8, 5.3 Hz, 1H) 1.12 (d, J=6.3 Hz, 3H) 0.90 (s, 9H) 0.09 (s, 6H). was quenched with sat. NH4Cl (5 mL) The mixture was diluted with H2O and hexanes was extracted with hexanes (3×) The combined organic phase was washed with brine dried (Na2SO4) concentrated The crude product was purified by flash chromatography (0 to 60% ethyl acetate/hexanes)

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

Procedure: To a solution of (S)-methyl 2-hydroxypropanoate (1.00 g, 9.61 mmol) in DMF (10 mL) at rt, were added imidazole (0.981 g, 14.41 mmol) and TBS-Cl (1.737 g, 11.53 mmol). The mixture was stirred at rt for 3 h. The reaction mixture was diluted with hexanes. The organic phase was washed with water (2×) and brine, dried (Na2SO4) and concentrated. The crude product was purified by flash chromatography (0 to 10% ethyl acetate/hexanes) to give 17A (1.73 g, 7.92 mmol, 82% yield) as a colorless oil. 1H NMR (400 MHz, chloroform-d) δ ppm 4.34 (q, J=6.7 Hz, 1H) 3.72 (s, 3H) 1.40 (d, J=6.8 Hz, 3H) 0.90 (s, 8H) 0.09 (d, J=10.8 Hz, 6H). The organic phase was washed with water (2×) and brine dried (Na2SO4) concentrated The crude product was purified by flash chromatography (0 to 10% ethyl acetate/hexanes)