Two routes are described for the synthesis of(
4-1,5-cyclooctadiene)(
6-phosphinine)iron(0) complexes. A three-component reaction of iron vapor with CODand 2-(trimethylsilyl)-4,5-dimethylphosphinine at low temperature yields 20%(COD)(2-(trimethylsilyl)-4,5-dimethylphosphinine)Fe(0) (
3), whereas ligandexchange of one COD ligand of the in situprepared metal vapor product (COD)
2Fe by2-(trimethylsilyl)-4,5-dimethylphosphinine or(
1-2-chloro-4,5-dimethylphosphinine)Cr(CO)
5gives corresponding (COD)(phosphinine)Fe(0)complexes in more than 80% isolated yield. As the phosphininederivatives are prochiral,complexation leads to the racemate of two enantiomers. Bothenantiomers are found in theunit cell of single crystalline
3 and are related by aninversion center. Complex
3 is a novelroom-temperature catalyst for the [2 + 2 + 2] cyclic additionreaction of one molecule ofbutyronitrile with two molecules of methyl propargyl ether giving up to160 mol of pyridinederivatives/mol
3. A chemically robust species,
3is an air-stable crystalline material, butexposure to oxygen in solution causes slow decomposition.