Resolution of [Fe(CO)3(1—5-η-dienyl)]+ cations and assignment of absolute configuration by circular dichroism spectroscopy

Abstract

(2R)-(–)₅₈₉-[Fe(CO)₃(1—5-η-2-MeOC₆H₆)]⁺(1) and (2S)-(1) of high optical purity have been obtained by h.p.l.c. separation of the diastereoisomers from the reaction of racemic (2R, 2S)-(1) with (R)-(+)₅₈₉-1-phenylethylamine, and subsequent treatment with HBF₄; circular dichroism spectroscopy appears to provide a rapid method for the assignment of absolute configuration to chiral [Fe(CO)₃(π-hydrocarbon)]ⁿ⁺(hydrocarbon = cyclic diene or dienyl, n= 0 or 1) complexes.