The chemistry of co-ordinated ligands. Part II. Iron tricarbonyl complexes of some cyclohexadienes

Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes

“…In the case of 4 (e.g. X = OMe [21] ), the donor substituent is at an internal position, and the directing effect is w. [19] In these reaction sequences, the OEt and OMe groups serve next as leaving groups in the steps that re-form the cyclohexadienyl complexes. Treatment with acid removes [14,20] the leaving group, either directly or following an acid-catalysed rearrangement of the position of the haptyl section of the Abstract: A series of aryl-substituted cyclohexadienyliron complexes have been prepared by a general procedure that determines regioselectivity by correctly positioning leaving groups in the precursor complexes.…”

Über neue zweikernige Metallcarbonylkomplexe mit Cyclohexadienyl-cycloheptatrien-und Cyclohexadienyl-isonitril-Brücken/On New Dinuclear Metal Carbonyl Complexes with Cyclohexadienyl Cycloheptatriene and Cyclohexadienyl Isonitrile Bridges

“…Das iH-NMR-Spektrum zeigt einen in 5-Position substituierten Cyclohexadien-Ring, da die chemischen Verschiebungen der inneren und äußeren Protonen des Dien-Systems und der C6-Methylenprotonen nahezu identisch mit denjenigen von (C6H7CN)Fe(CO)3 [16] Wir danken der Deutschen Forschungsgemeinschaft und dem Verband der Chemischen Industrie e.V., Fonds der Chemischen Industrie, für die Unterstützung dieser Untersuchungen.…”

Synthesis, Molecular Structure, Fluxional Behavior, and Tricarbonyliron Transfer Reactions of (η4-1-Azabuta-1,3-diene)tricarbonyliron Complexes

“…[1] The parent complex, tricarbonyl(η 4 -cyclohexa-1,3-diene)iron (2), was prepared first in 1958 by Pauson via complexation of cyclohexa-1,3-diene (1a) with pentacarbonyliron under thermal reaction conditions (yield: 21%). [2] The yield of this complexation was later improved by photolytic reaction of cyclohexa-1,4-diene (1b) with pentacarbonyliron in benzene (yield: 56%), [3] by reaction of cyclohexa-1,4-diene (1b) with pentacarbonyliron in di-n-butyl ether at reflux (yield: 46%), [4] by reaction of cyclohexa-resulting tricarbonyl(η 5 -cyclohexadienylium)iron tetra-1,3-diene (1a) with nonacarbonyldiiron in tetrahydrofuran fluoroborate (3) can be utilized for regio-and stereoselecat reflux (yield: 43%), [5] and by photolytic reaction of cyclo-tive bond formation with a broad range of nucleophiles. [1] hexa-1,3-diene (1a) with pentacarbonyliron in hexane Projected synthetic applications of the complex salt 3 re-(yield: 77%) [5] (Scheme 1).…”

“…The variation of the reaction time for the transfer of the tricarbonyliron fragment to cyclohexa-1,3-diene (1a) was investigated for the complexes 10b, 10c, and 10g (Table 3). At all three different reaction times the transfer reagent turnover, the transfer of the tricarbonyliron fragment from 3.35 Å complex 10 to already generated corresponding free 1-azabuta-1,3-diene ligand 9 can compete with the desired transfer to 1a and finally becomes dominant if only a 1:1 ratio Table 3. Variation of the reaction time for the tricarbonyliron transfer to 1a using the complexes 10b, c, g…”