3-Hepten-2-one, 5-methyl- synthesis

Yield:5090-16-4 74%

Reaction Conditions:

in dichloromethane at 20; for 72 h;

Steps:

5.1.87. 5-Methylhepta-3-en-2-one (66)

To a stirred solution of 2-methylbutyraldehyde (68.6 g, 797 mmol) in CH₂Cl₂ (650 mL) was added Ph₃PCHCOMe (254 g, 797 mmol) at room temperature. After being stirred for 3 days, the reaction mixture was evaporated and diluted with hexane. The resulting precipitates were removed by filtration and the filtrate was evaporated. The resulting residue was purified by column chromatography on silica gel (EtOAc/hexane, 10/90-33/67) to afford 66 (149 g, 74% yield) as a colorless oil. ¹H NMR (300 MHz, CDCl₃) δ 6.66 (dd, J = 16.0, 7.8 Hz, 1H), 6.01 (dd, J = 16.0, 1.1 Hz, 1H), 2.22 (s, 3H), 2.21 (m, 1H), 1.47-1.33 (m, 2H), 1.03 (d, J = 6.8 Hz, 3H), 0.86 (t, J = 7.5 Hz, 3H).

References:

Saito, Tetsuji;Obitsu, Tetsuo;Kohno, Hiroshi;Sugimoto, Isamu;Matsushita, Takeshi;Nishiyama, Taihei;Hirota, Tomoko;Takeda, Hiroyuki;Matsumura, Naoya;Ueno, Sonoko;Kishi, Akihiro;Kagamiishi, Yoshifumi;Nakai, Hisao;Takaoka, Yoshikazu [Bioorganic and Medicinal Chemistry,2012,vol. 20,# 2,p. 1122 - 1138] Location in patent:experimental part