camphor-10-sulfonic acid in methanol T=20°C;

1: propargyl alcohol With ethylmagnesium bromide in tetrahydrofuran T=23 - 80°C; 2: cycloheptanone in tetrahydrofuran T=23 - 25°C; Grignard reaction; 3: With ammonium chloride in tetrahydrofuran; water

1.1: BuLi; TMEDA / tetrahydrofuran / -78 °C 1.2: tetrahydrofuran / -78 - 20 °C 2.1: camphorsulfonic acid / methanol / 20 °C View Scheme

n-butyllithium 1.) THF, hexane, -78 deg C, 2 h, 2.) THF, hexane, -65 deg C, 6 h; Yield given. Multistep reaction;