Reaction Steps
LDA (2M in THF, 3.1 mL, 6.2 mmol) was added to a solution of 2,6-dimethylphenoxy propionate (1.10 g, 6.2 mmol) in anhydrous THF (12.4 mL) at −78° C., followed by stirring for 1 h at −78° C. The crude aldehyde 27 (4.1 mmol) from above dissolved in anhydrous THF (10 mL) was added slowly at −78° C. After 2 h at room temperature, the mixture was quenched with saturated aqueous NH4Cl (10 mL) and extracted with CH2Cl2 (3×10 mL). The combined organic layer was dried over anhydrous MgSO4, evaporated and chromatographed (hexane/EtOAc 4:1) to yield 29 (1.67 g, 2.99 mmol) as a colorless oil: IR (CHCl3) 3120, 2857, 1744, 1514, 1216, 1099 cm−1; 1H NMR (300 MHz, CDCl3) δ 7.26 (d, 2H, J=8.4 Hz), 6.87 (d, 2H, J=8.4 Hz), 4.62 (d, 1H, J=11.1 Hz), 4.40 (d, 1H, J=11.1 Hz), 4.06 (d, 1H, J=6.8 Hz), 3.79 (s, 3H), 3.66–3.61 (m, 3H), 2.89 (m, 1H), 2.19 (s, 6H), 1.86 (m, 2H), 1.55 (m, 3H); 1.27 (d, 3H, J=6.8 Hz), 1.01 (d, 3H, J=6.9 Hz), 0.93 (s, 9H), 0.07 (s, 6H); 13C NMR (75 MHz, CDCl3) δ 173.5, 159.2, 148.0, 130.0, 129.9, 129.4, 128.4, 125.6, 113.8, 83.5, 70.7, 62.9, 55.1, 44.0, 35.6, 28.7, 26.6, 25.8, 18.2, 16.3, 14.2, 5.7, −5.3; HRMS (EI) calcd for C32H50O6Si 558.3377, found 558.3392.
