1.1: potassium tert-butylate / tetrahydrofuran / 4 h / 16 - 25 °C 1.2: 1.83 h / 20 - 21 °C 2.1: AlCl3, aluminium chloride; 1,1,3,3-tetramethyldisiloxane / toluene / 2.5 h / 18 - 26 °C 3.1: isopropylmagnesium chloride; lithium chloride / tetrahydrofuran / 1.83 h / -21 - -15 °C 3.2: 2.92 h / -25 - -13 °C View Scheme