“…but it is doubtful whether this same mechanism can be applied to the hydrocarbon syntheses of Fittig, Wurtz, and Ullmann, which are usually carried out in inert solvents: e.g., 2C2H6I + 2Na -> C2H5C2H6 + 2NaI 2C6H6I + 2Cu -> C6H6C6H6 + Cu2I2 since the reactions may proceed instead by means of the formation of organometallic compounds, e.g., C2H6Br + 2Na -> (C2H6)-Na+ + NaBr C2H6Na + BrC2H6 -> C2H6C2H6 + NaBr and evidence can be adduced in support of each theory (167,3,139,169,173,103).…”