1: 89 percent / toluene-p-sulphonic acid / 168 h / Heating 2: water / stannic chloride / CH2Cl2 View Scheme

1: 89 percent / toluene-p-sulphonic acid / 168 h / Heating 2: water / stannic chloride / CH2Cl2 3: 65 percent / triethylamine / benzene / 168 h / Ambient temperature View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis 3: 75.4 percent / toluene-p-sulphonic acid monohydrate / 24 h / Heating 4: water / stannic chloride / CH2Cl2 View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis 3: 75.4 percent / toluene-p-sulphonic acid monohydrate / 24 h / Heating 4: water / stannic chloride / CH2Cl2 5: 97 percent / triethylamine / 1 h 6: stannic chloride View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis 3: 75.4 percent / toluene-p-sulphonic acid monohydrate / 24 h / Heating 4: water / stannic chloride / CH2Cl2 5: 97 percent / triethylamine / 1 h View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis 3: 75.4 percent / toluene-p-sulphonic acid monohydrate / 24 h / Heating 4: water / stannic chloride / CH2Cl2 5: 97 percent / triethylamine / 1 h View Scheme

1: 88 percent / 1,8-diazabicyclo<5.4.0>undec-7-ene / CH2Cl2 / 5 h / Heating 2: neat (no solvent) / pyrolysis 3: 75.4 percent / toluene-p-sulphonic acid monohydrate / 24 h / Heating 4: water / stannic chloride / CH2Cl2 5: 76 percent / triethylamine / benzene View Scheme