1: 78 percent / 2,3-dichloro-5,6-dicyanobenzoquinone / benzene / 1 h / Heating 2: 36 percent / tetrabutylammonium fluoride / tetrahydrofuran / Ambient temperature 3: 59 percent / Amberlyst A15 resin (H(1+) form) / CH2Cl2 / 10 h / Ambient temperature View Scheme

With  2,3-dicyano-5,6-dichloro-p-benzoquinone in  benzene 1 h;  Heating;   

Multi-step reaction with 2 steps 1: 78 percent / 2,3-dichloro-5,6-dicyanobenzoquinone / benzene / 1 h / Heating2: 36 percent / tetrabutylammonium fluoride / tetrahydrofuran / Ambient temperature