Regioselective, stereoselective, and conformationally controlled synthesis of (η4-tetraarylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes

Doyle J. Cassar, Elisabeth Nagaradja, David C. D. Butler, Didier Villemin, Christopher J. Richards

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8 Citations (Scopus)


The Friedel–Crafts reaction of (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl3) and tetraacylated products (>4 equiv of RCOCl/AlCl3) were synthesized. Reaction of PhCC(o-RC6H4) (R = Me, i-Pr) with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel–Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.
Original languageEnglish
Pages (from-to)894-897
Number of pages4
JournalOrganic Letters
Issue number3
Publication statusPublished - 2012

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