Metalation Reactions XIII. Effect of the Metalating Agent on the Metalation of Acetylenes

Methyl‐lithium gave with 1‐phenyl‐1‐propyne and 1‐phenyl‐1‐butyne preferentially the products of monometalation although dimetalation of these compounds is faster than monometalation when butyl‐lithium is used. The product of protonation of dilithiophenylbutyne depends on the condition of the reaction. In the presence of starting material, 4‐phenylbut‐2‐yne and in its absence, 1‐phenylbuta‐1,2‐diene is obtained. Alkylation, silylation and protonation of the lithium derivatives was studied.