1.1: Et3N; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 0.08 h / 0 °C 1.2: 73 percent / DMAP / toluene; tetrahydrofuran / 0.5 h / 20 °C 2.1: 82 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2; H2O / 2.5 h 3.1: 90 percent / trifluoroacetic acid / CH2Cl2 / 2.5 h / 20 °C 4.1: 30 percent aq. H2O2; KHCO3 / methanol; acetonitrile / 24 h / 20 °C View Scheme

1.1: Et3N; 2,4,6-trichlorobenzoyl chloride / tetrahydrofuran / 0.08 h / 0 °C 1.2: 73 percent / DMAP / toluene; tetrahydrofuran / 0.5 h / 20 °C 2.1: 82 percent / 2,3-dichloro-5,6-dicyano-1,4-benzoquinone / CH2Cl2; H2O / 2.5 h 3.1: 90 percent / trifluoroacetic acid / CH2Cl2 / 2.5 h / 20 °C View Scheme