Triethylamine → (+/-) 3-Ethoxy-4-methyl-4-propyl-2-cyclobuten-1-one

反応式

[CH3:1][CH:2]([CH2:6][CH2:7][CH3:8])[C:3](Cl)=[O:4].[CH2:9]([O:11][C:12]#[CH:13])[CH3:10].C(N(CC)CC)C>CCOCC>[CH2:12]([O:11][C:9]1[C:2]([CH3:1])([CH2:6][CH2:7][CH3:8])[C:3](=[O:4])[CH:10]=1)[CH3:13]

参加物

実験手順

The title compound was prepared using a modification of the method of Wasserman, H. H. et al [J. Org. Chem, 38, 1451-1455, (1973)]; to a solution of 2-methyl pentanoyl chloride (3.91 ml) and ethyl ethynylether (5 g, 40% solution in hexanes, 28.6 mmol) in Et2O (35 ml) at room temperature was added triethylamine (9.9 ml), with stirring. The reaction was warmed to 50° and stirred for 72 h prior to cooling and filtration. The filtrate was concentrated in vacuo and the residual oil chromatographed (SiO2; hexanes 80:EtOAc 20) to give the title compound as a colourless oil (3.71 g, 17.9 mmol, 77%). δH (CDCl3, 300K), 4.84 (1H, s), 4.24-3.98 (2H, m), 2.04 (3H, s), 1.56-1.43 (4H, m), 1.30-1.26 (3H, m), 0.91 (3H, t, J 7.3 Hz). m/z (ES+, 70V) 178.1 (MH+).