The general procedure for the synthesis of 1,7-dichloro-4-heptanone from dicyclopropyl ketone was as follows: a 10-fold excess of HCl gas was passed into the dicyclopropyl ketone (15.00 g, 136.16 mmol) for 30 minutes. The reaction mixture was stirred at room temperature for 3 hours and then passed through HCl gas again for 30 minutes. Upon completion of the reaction, a brown oily crude product (24.93 g, 100% yield) was obtained, which could be used in subsequent steps without further purification. The structure of the product was confirmed by the following characterization data: 1H NMR (300 MHz, CDCl3) δ (ppm) 2.02 (m, 4H), 2.61 (t, 4H, J=7.0 Hz), 3.55 (t, 4H, J=6.3 Hz); 13C NMR (75 MHz, [D4] MeOH) δ (ppm) 27.6,40.3, 45.2,210.7; HRMS (APCI; MeOH) m/z (%) 183 (100); Calculated value for m/z [M + H]+ C7H13Cl2O+: 183.0337, measured value 183.0337. molecular formula: C7H12Cl2O (molecular weight 183.08).
