Reaction of (η5‐C5H5)Fe(CO)2I with Anionic Bidentate Phosphine Ligands PPh2(o‐C6H4NHLi) or PPh2(o‐C6H4OLi)

The o‐substituted hybrid phenylphosphines, PPh₂(o‐C₆H₄NH₂) and PPh₂(o‐C₆H₄OH), could be deprotonated with LDA or n‐BuLi to yield PPh₂(o‐C₆H₄NHLi) and PPh₂(o‐C₆H₄OLi), respectively. When added to a solution of (η⁵‐C₅H₅)Fe(CO)₂I at room temperature, these two lithiated reagents produce a chelated neutral complex 1 (η⁵‐C₅H₅)Fe(CO)[C(O)NH(o‐C₆H₄)PPh₂‐C,P‐η²] for the former and mainly a zwitterionic complex 2 , (η⁵‐C₅H₅)Fe⁺(CO)₂[PPh₂(o‐C₆H₄O^?)] for the latter. Complex 1 could easily be protonated and then decarbonylated to give 4 [(η⁵‐C₅H₅)Fe(CO){NH₂(o‐C₆H₄)PPh₂‐N,P‐η²}⁺]. Complexes 1 and 4‐I have been crystallographically characterized with X‐ray diffraction.     

α‐Chiral Acetylenes Having an All‐Carbon Quaternary Center: Phase Transfer Catalyzed Enantioselective α Alkylation of α‐Alkyl‐α‐alkynyl Esters

Going through the phases : The title reaction was found to proceed by an initial base‐mediated isomerization to allenyl esters and subsequent phase transfer catalyzed alkylation at the α position of the ester (see scheme).