Reactivity of 1-substituted (pentadienyl)iron(1+) cations: Regioselectivity for addition of malonate nucleophiles; formation of (pentenediyl)- and (diene) iron complexes

Abstract

Abstract The reaction of six 1-substituted (pentadienyl)iron cations ( 1–6 ) with malonate anions was examined. The electronic nature of substituents present on the pentadienyl ligand, the steric bulk of the malonate anion, and the peripheral ligands about the iron metal were varied. (Pentenediyl)- and/or (diene)iron complexes, resulting from attack at either an internal (C2/C4) or terminal (C1/C5) pentadienyl carbon, were isolated as products. These results indicate that strongly electron withdrawing substituents direct malonate attack at the internal pentadienyl site, while strongly electron donating substituents direct malonate attack at the terminal pentadienyl site. The single crystal X-ray diffraction analysis of two (pentenediyl)iron complexes ( 7a and 7b ) are reported.