Sodium bis(trimethylsilyl)amide → Dibenzyl-4-methyleneheptanedioate

Participants

Reaction Conditions

Reaction Steps

Methyltriphenylphosphonium bromide (536 mg, 1.5 mmol) was suspended in anhydrous THF (1.0 mL) at −5C. A THF solution of NaHMDS (1.0 M, 1.5 mL, 1.5 mmol) was added dropwise to keep the temperature below 0° C. The mixture was stirred at 0° C. for 0.5 h before cooled to −78° C. To this ylid solution was added a solution of dibenzyl-4-oxopimelate (354 mg, 1.0 mmol) in THF (1.0 mL) dropwise to keep the temperature below −50° C. The temperature was allowed to rise to room temperature in 1.5 h with stirring after addition. The reaction mixture was then poured in icy water (25 mL) and extracted with Et2O (2×25 mL). The organic layer was washed with brine (20 mL) and dried over Na2SO4. The solvent was removed under vacuum and the residue was subjected to silica chromatography (EtOAc/hexanes, up to 1/10) to give compound B4 (197 mg). The yield was 56%. 1H NMR (200 MHz, CDCl3) δ 7.37 (m, 10H), 5.11 (s, 4H), 4.78 (d, 2H, J=1.1 Hz), 2.53 (m, 4H), 2.39 (m, 4H); 13C NMR (50 MHz, CDCl3) δ 173.3, 146.6, 136.4, 129.0, 128.7, 110.5, 66.9, 33.2, 31.6; MS (MALDI-TOF) calcd (M+Na+) 375.4, found 375.6.

Provenance & Evidence