1: I2 / tetrahydrofuran 2: DBU / tetrahydrofuran 3: DBU / DMAP / CH2Cl2 View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene; 4-(N,N-dimethlyamino)pyridine in dichloromethane Yield given;

1: 1.) n-BuLi / 1.) THF, hexane, 0 deg C, 1 h, 2.) THF, -78 deg C to RT 2: 1.) iodine, 2.) DBU / 1.) THF, RT, 15 h, 2.) THF, RT, 2 h 3: DBU, DMAP / CH2Cl2 / Ambient temperature View Scheme

4-(N,N-dimethlyamino)pyridine; 1,8-diazabicyclo[5.4.0]undec-7-ene in dichloromethane Ambient temperature; Yield given;