Triethylamine → Methyl-9-t-butyldiphenylsilyloxy-nonanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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).

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