Carbamate Directed peri-C–H Alkynylation: Application to the Synthesis of Zethrenes

The Rh(III)-catalyzed regioselective alkynylation of 1-naphtyl and 1-pyrenyl carbamates and related substrates with bromoacetylenes allows introducing regioselectively an alkyne in the peri position of readily available amino-substituted polycyclic aromatic hydrocarbons. We have applied this methodology for the synthesis of new vertically π-extended zethrene derivatives with two pyrene subunits. Further oxidative cyclodehydrogenation forms regioselectivity a hexabenzo[def,i,lm,qrs,v,yz]pyranthrene, which has been characterized by electron diffraction.