1: cyclohexanone With lithium diisopropyl amide in tetrahydrofuran; n-heptane; ethylbenzene T=-78°C; 1 h; 2: o-chloro benzoic acid chloride in tetrahydrofuran; n-heptane; ethylbenzene T=-78 - 20°C;

1.1: polymer bound piperazine; p-TsOH; 4 A MS / benzene / 24 h / Heating 1.2: Et3N / CH2Cl2 1.3: HCl; water / tetrahydrofuran / 0.33 h / 20 °C 2.1: 100 percent / aq. NaOH View Scheme