Gold-catalyzed cascade cyclizations of 1,6-diynyl carbonates to benzo[b]fluorenes involving arylation of oxocarbenium ion intermediates and decarboxylative etherification.

Rearranged: The described gold-catalyzed cycloisomerizations give access to highly substituted benzo[b]fluorenes under mild reaction conditions (see scheme). Experimental results indicate that the in situ formed oxocarbenium ion intermediates, derived from gold-catalyzed 3,3-rearrangement and 6-endo-dig cyclization, undergo intramolecular arylation and subsequent decarboxylative etherification to furnish the final ether products.