n-butyllithium in diethyl ether

1: 88 percent / pyridinium dichromate / dimethylformamide / Ambient temperature 2: 1.) polyphosphoric acid (PPA), 2.) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) / 1.) 110 deg C, 2 h, 2.) benzene, reflux, 30 min View Scheme

dipyridinium dichromate in N,N-dimethyl-formamide Ambient temperature;