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Unsaturated Organic Derivatives of Phosphaferrocene – Synthesis and Reactivity of Vinyl‐ and Alkynylphosphaferrocenes
Author(s) -
Faßbender Julia,
Frank Walter,
Ganter Christian
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200588
Subject(s) - chemistry , hydroboration , deprotonation , protonation , substituent , reactivity (psychology) , wittig reaction , derivative (finance) , medicinal chemistry , electrophile , stereochemistry , organic chemistry , catalysis , medicine , ion , alternative medicine , pathology , financial economics , economics
Starting from 2‐formyl‐3,4‐dimethylphosphaferrocene, a series of vinyl‐substituted phosphaferrocenes was prepared by Wittig and related olefination reactions. The parent 3,4‐dimethyl‐2‐vinylphosphaferrocene ( 2 ) could be selectively converted to either the terminal or branched alcohols 8b and 8a by hydroboration/oxidation or protonation in aqueous solution, respectively. Elimination of HBr from 2‐bromovinylphosphaferrocene 9 provided access to the 2‐ethynylphosphaferrocene derivative 10 , which could be converted to other alkynes by deprotonation and electrophilic quench. Additionally, the syntheses of the 2‐cyano‐ ( 15 ) and 2‐(ethoxycarbonyl)phosphaferrocene derivative 13 are reported. Several new phosphaferrocenes were converted into their respective Fe(CO) 4 complexes, which were investigated by IR spectroscopy. The CO stretching vibrations were found to depend on the nature of the substituent in the 2‐position and the cyano compound 15 was identified as the least electron‐donating ligand. Reaction of the alkynylphosphaferrocenes 10 and 11 with Co 2 (CO) 8 afforded the respective dimetallatetrahedrane complexes 24 and 25 . The molecular structures of compounds 12 , 21 and 25 have been determined by X‐ray diffraction analysis.