Abstract
Starting from 1,1-diferrocenyl-1-methoxypropyne, the first air-stable C5-cumulenium salt (Fc)2CCCCC(Fc)+BF4- (Fc = ferrocenyl) can be synthesized by a metalation, iodination, cross-coupling, and dehydration sequence. Attempted nucleophilic attack of ferrocenyl carbanion affords only radical decomposition products and none of the desired tetraferrocenyl-C5-cumulene (Fc)2CCCCC(Fc)2. In contrast, reaction with phenyllithium yields the nucleophilic addition product (Fc)2CCC(R)C⋮CFc (R = C6H5) with 100% regioselectivity. Starting from diferrocenyl ketone, the first air-stable protonated C5-cumulenium salt (Fc)2CCHCCC(Fc)2+BF4- is prepared by stepwise substitution of propyne with diferrocenyl(methoxy)methyl groups and subsequent 2-fold dehydration. Addition of methoxide affords (Fc)2CCC(R)CΗC(Fc)2 (R = OCH3); attempted conversion to tetraferrocenyl-C5-cumulene (Fc)2CCCCC(Fc)2 by thermal elimination of methanol in vacuo fails but yields an unusual cyclobutene dimer with eight ferrocenyl substituents. Finally, de...
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
