Lithium hydroxide, monohydrate → HCID 22137606, compound

Participants

Reaction Steps

A mixture of the above aldehyde (21) (2.10 g, 10 mmol), triethyl trans-4-phosphono-2-butenoate (3.0 g, 12 mmol), LiOH—H2O (510 mg, 12 mmol) and 4A molecular sieve (5 g) in THF (100 mL) was heated at reflux 1.5 hours. The molecular sieve was filtered through a short pad of Celite and washed with EtOAc (100 mL) and the filtrate concentrated to give sticky brown oil. The oily residue was diluted with 5% citric acid and extracted thrice with 100 mL of EtOAc. The combined extracts were washed with NaHCO3, brine, then dried over Na2SO4 and concentrated. Purification by flash chromatography (EtOAc:Hexanes=1:5) gave a white solid (22) (2.95 g, 95%) of the desired compound. 1H NMR (500 MHz, CDCL3) δ 7.24 (dd, J=15.5, 10.5 Hz, 1H), 6.16 (dd, J=15.5, 10.5 Hz, 1H), 6.04 (dd, J=15.5, 7.0 Hz, 1H), 5.82 (d, J=15.5 Hz, 1H), 4.20 (q, J=7.0 Hz, 2H), 4.10 (m, 2H), 2.75 (m, 2H), 2.25 (m, 1H), 1.71 (m, 2H), 1.46 (s, 9H), 1.34 (m, 2H), 1.29 (t, J=7.0 Hz, 3H); MS (ESI+) m/z 210.75 (M+H+-boc).

Provenance & Evidence