BIS(CYCLOPENTADIENYLIRON)ARENE COMPLEXES - A NEW ROUTE TO THE SYNTHESIS AND FUNCTIONALIZATION OF POLYAROMATIC ETHERS

A new development in the chemistry of arenes activated toward S(N)Ar r eactions by the cyclopentadienyliron (FeCp+) moiety is presented in th is work. A class of diiron complexes of diphenoxybenzenes was prepared in a highly efficient and very mild fashion. Dihydroxyaromatic compou nds served as dinucleophiles, allowing for the formation of the diiron complexes. This could be achieved in either a one or two step procedu re. A wide variety of dinucleophiles were incorporated into this study , as well as a number of FeCp+ activated arenes. It is shown that thes e reactions are not inhibited by bulky substituents on either the dinu cleophiles or activated arenes. The diiron complexes themselves could also undergo S(N)Ar reactions, provided that the complexed arenes cont ained a chlorine substituent. This allowed for the functionalization o f the complexes with species that could not be introduced directly in their syntheses. The carbon nucleophiles generated from ethyl cyanoace tate or (phenylsulfonyl)acetonitrile could be attached to the complexe d ethers in this manner. The FeCp+ moieties were removed easily by pho tolytic demetalation which allowed for the recovery of a wide range of functionalized diphenoxybenzenes. This methodology is advantageous ov er all those previously reported and should be a practical route to th e synthesis of aromatic ethers.