Iron carbonyl complexes from Schiff bases. Part II. Products from the anils of benzophenone, 2-naphthaldehyde and thiophen-2-carbaldehyde and 3-carbaldehyde and mechanistic studies with deuterium-labelled anils

Abstract

Complexes are obtained from the anils named in the title and from that of tetrafluorobenzaldehyde, adventitiously present in commercial pentafluorobenzaldehyde. The β-naphthaldehyde derivative is substituted by iron in the 3 position. The complex from thiophen-2-carbaldehyde has been hydrogenolysed to yield the ferra-dihydro-pyrrole complex (V; R = Et). Experiments with mono-, penta-, and hexa-deuteriobenzylideneanilines and related acetophenone complexes have shown that hydrogen atoms migrate to the methine carbon only from the ortho-position during complex formation. The process is largely intramolecular.