Abstract
The compounds [CpFe(Prophos)Cl] and [CpFe(Prophos)I] were prepared in photochemical reactions of [CpFe(CO)(2)Cl] and [CpFe(CO)(2)I] with (R)-Prophos. They consist of pairs of R-Fe,R-C and S-Fe,R-C diastereomers which only differ in the configuration at the metal atom. The diastereomerically pure compounds (S-Fe,R-C)-[CpFe(Prophos)Cl] and (R-Fe,R-C)-[CpFe(Prophos)I], which have the same relative ...
Abstract
The compounds [CpFe(Prophos)Cl] and [CpFe(Prophos)I] were prepared in photochemical reactions of [CpFe(CO)(2)Cl] and [CpFe(CO)(2)I] with (R)-Prophos. They consist of pairs of R-Fe,R-C and S-Fe,R-C diastereomers which only differ in the configuration at the metal atom. The diastereomerically pure compounds (S-Fe,R-C)-[CpFe(Prophos)Cl] and (R-Fe,R-C)-[CpFe(Prophos)I], which have the same relative configurations, were isolated. They epimerize via change of the Fe configuration and approach the equilibria (R-Fe,R-C)-/(S-Fe,R-C)-[CpFe(Prophos)Cl] = 5/95 and (R-Fe,R-C)-/(S-Fe,R-C)-[CpFe(Prophos)I] = 95/5 in first-order reactions with half-lives of 43 min at 20 degrees C and 50 min at 50 degrees C in C6D6, respectively. The reaction of (R-Fe,R-C)-/(S-Fe,R-C)-[CpFe(Prophos)I] = 95/5 with KCN afforded the cyano complex [CpFe(Prophos)CN] in the diastereomer ratio R-Fe,R-C/S-Fe, R-C = 50/50. Both diastereomers (R-Fe,R-C)- and (S-Fe,R-C)-[CpFe(Prophos)CN] could be isolated diastereomerically pure. The compounds (R-Fe,R-C)- and (S-Fe,R-C)-[CpFe(Prophos)CN] are configurationally stable at the metal center. There is no diastereomer interconversion, not even at higher temperatures. The carbonyl complexes [CpFe(Prophos)CO]I, [CpFe(Prophos)CO]PF6, and [IndFe-(Prophos)CO]I were prepared in thermal reactions of [CpFe(CO)(2)I] and [IndFe(CO2)I] with (R)-Prophos or in an autoclave reaction of [CpFe(Prophos)I]/NH4PF6 with CO under pressure. All the carbonyl complexes are configurationally stable at the metal center. Seven diastereomers were characterized by X-ray crystallography. 'Including the two diastereomers (R-Fe,R-C)-[CpRu(Prophos)Br] and (R-Fe,R-C)-[CpRu(Prophos)I], a conformational analysis of the M-Prophos chelate ring was carried out, resulting in characteristic differences between major and minor diastereomers.
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