Molecular mechanics analysis of structure and diastereoselectivity toward lithiation in amido- and alpha-aminoferrocene complexes

J A S Howell, P C Yates, N Fey

Research output: Contribution to journalReview article (Academic Journal)peer-review

15 Citations (Scopus)

Abstract

A molecular mechanics force field has been developed for the conformational analysis of amido- and alpha-aminoferrocenes. Parameterization for ring-substituent rotational barriers in amidoferrocenes and other cross-conjugated derivatives have been calculated using DFT on both the free and complexed cyclopentadienyl ligand. Modeled structures of (diisopropylamido)- and (dimethylamido)ferrocene and N,N-dimethyl-alpha-ferrocenylethylamine are in agreement with those determined through single-crystal X-ray diffraction. The diastereoselective lithiation of N,N-dimethylferrocenylethylamine and sparteine-mediated enantioselective lithiation of (diisopropylamido)ferrocene using MeLi have been modeled through an assumed reversible adduct formation at the amine nitrogen or amide oxygen, followed by an irreversible ring lithiation. Results indicate that selectivity results from ring lithiation via the adduct conformer with the shortest C-H-ring- - - H3C-Li interaction.

Original languageEnglish
Pages (from-to)5272-5286
Number of pages15
JournalOrganometallics
Volume21
Issue number24
DOIs
Publication statusPublished - 25 Nov 2002

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