Synthesis of 1-(2-ethynyl-6-methylphenyl)- and 1-(2-ethynyl-6-methoxyphenyl)-naphthalene and their cyclization

A Suzuki cross-coupling reaction of hindered 2-bromo-1-trimethylsilylethynylbenzenes with 1-naphthaleneboronic acid yielding (2-ethynylphenyl)naphthalenes has been achieved. Their subsequent cyclization was carried out, giving benzo[c]phenanthrenes, without the use of photochemical procedures.