Tetrahydro-2-(2-propynyloxy)-2H-pyran → 1-(3,4-Dichlorophenyl)-4-[(oxan-2-yl)oxy]but-2-yn-1-one

Participants

Reaction Conditions

Reaction Steps

To a mixture of 3,4-dichloro-N-methoxy-N-methyl-benzamide from Example 511 (0.68 g, 2.9 mmol) and tetrahydro-2-(2-propynyloxy)-2H-pyran (0.40 mL, 2.9 mmol) in 3.5 mL of dry THF at −25° C. was added lithium bis(trimethylsilyl)amide (LHMDS, 1 M in THF) between −25° C. and −18° C. The reaction mass was stirred at that temperature range for 1 h. The reaction was quenched with 10 mL of 1 M citric acid and was allowed to warm to 10° C. EtOAc (5 mL) was added and the mass was stirred for 15 min. The pH of the aqueous layer was 5. The layers were separated and the organic layer was concentrated to give a light yellow oil (110%, including residual solvent). HPLC (Method U): Rt=15.42 min. MS (ES+): mass calculated for C15H14Cl2O3, 312.03; m/z found, 325.1 [M+Na]+. 1H NMR (400 MHz, CDCl3): 8.19 (d, J=2 Hz, 1H), 7.95 (dd, J=8.4, 2.1 Hz, 1H), 7.57 (d, J=8.4 Hz, 1H), 4.94-4.81 (m, 1H), 4.56 (s, 2H), 3.97-3.82 (m, 1H), 3.71-3.55 (m, 1H), 1.91-1.54 (m, 6H). 13C NMR (100 MHz, CDCl3): 175.0, 139.0, 136.0, 133.4, 131.4, 131.2, 130.8, 128.3, 97.7, 92, 82.9, 62.2, 54.2, 30.1, 25.2, 18.9.

Provenance & Evidence