Reaction #75464

Reaction equation

NH4Cl

methyl-9-hydroxy-nonanoate

Et3N

t-butylchlorodiphenylsilane

→

Methyl-9-t-butyldiphenylsilyloxy-nonanoate

Solvents

CH2Cl2

Conditions

Workup

1. 1
   Otherthe mixture was partitioned between CH2Cl2 (100 mL) and H2O (100 mL)
2. 2
   DryingThe organic layer was dried (Na2SO4)
3. 3
   Concentrationconcentrated under reduced pressure
4. 4
   WashChromatography (SiO2, 5 cm×15 cm, 0-5% EtOAc-hexanes gradient elution)
5. 5
   Otherafforded the intermeidate as a clear, colorless oil (1.22 g, 1.831 theoretical, 64.1%)

Procedure

A solution of methyl-9-hydroxy-nonanoate (0.838 g, 4.46 mmol, 1.0 equiv: Aldrich) in CH2Cl2 (15 mL, 0.3 M) was treated successively with Et3N (0.75 mL, 5.38 mmol, 1.2 equiv), t-butylchlorodiphenylsilane (1.28 mL, 4.93 mmol, 1.1 equiv), and DMAP (0.180 g, 1.48 mmol, 0.33 equiv), and the reaction mixture was stirred at 25° C. for 12 h. Saturated aqueous NH4Cl was added to the reaction mixture and the mixture was partitioned between CH2Cl2 (100 mL) and H2O (100 mL). The organic layer was dried (Na2SO4) and concentrated under reduced pressure. Chromatography (SiO2, 5 cm×15 cm, 0-5% EtOAc-hexanes gradient elution) afforded the intermeidate as a clear, colorless oil (1.22 g, 1.831 theoretical, 64.1%): 1H NMR (CDCl3, 250 MHz) δ 7.66 (m, 4H, ArH), 7.38 (m, 6H, ArH), 3.67-3.62 (m, 5H, C(O)OCH3 and CH2OTBDPS), 2.30 (t, 2H, J=7.4 Hz, CH2C(O)OCH3), 1.58 (m, 4H, CH2CH2OTBDPS and CH2CH2C(O)OCH3), 1.28 (b s, 8H, alkyl protons), 1.05 (s, 9H, C(CH3)3).

Source