1.1: titanium tetrachloride; N-ethyl-N,N-diisopropylamine / dichloromethane / 1 h / -78 °C / |Inert atmosphere 1.2: 15 h / -12 °C / |Inert atmosphere 2.1: 2,6-dimethylpyridine / dichloromethane / 5 h / -45 - 20 °C / |Inert atmosphere 3.1: (SPY-5-31)-dichloro-(κ2(C,O)-(2-isopropyloxybenzylidene))(1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene)ruthenium / 1,2-dichloro-ethane / 4 h / 80 °C / |Inert atmosphere 4.1: trifluoroacetic acid / dichloromethane / 2 h / -20 - 0 °C / |Inert atmosphere View Scheme