Synthesis of substituted anthracenes, pentaphenes and trinaphthylenes via alkyne-cyclotrimerization reaction

The [2+2+2] cycloaddition reaction of 1,6-diynes 3 with 4-aryl-2-butyn-1-ols 4 and the following oxidation of the resulting benzylic alcohols to the aldehydes 1 and then treatment with an acid catalyst provided annulated anthracenes 2 in good yields.

Novel substituted anthracene derivatives including annulated pentaphenes and trinaphthylenes were synthesized through alkyne [2+2+2] cycloaddition as a key reaction.