Synthesis, characterization and crystal structures of boron-containing intermediates in the reductive amination of ferrocenecarboxaldehyde to a bis(ferrocenylmethyl) amine

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• 作者：Nathan C. Tice ; Sean Parkin ; John P. Selegue
• 关键词：Ferrocene ; Reductive amination ; Ammonium cyanoborohydride ; Amine– ; cyanoborane adduct ; X-ray crystal structure ; NMR spectroscopy
• 刊名：Journal of Organometallic Chemistry
• 出版年：2007
• 出版时间：15 January 2007
• 年：2007
• 卷：692
• 期：4
• 页码：791-800
• 全文大小：645 K

文摘

Reaction of ferrocenecarboxaldehyde with aqueous methylamine leads to [(methylimino)methyl]ferrocene, which is reduced to N-(ferrocenylmethyl)-N-methylamine by NaBH₄. This amine reacts with ferrocenecarboxaldehyde and NaCNBH₃ to give the tertiary ammonium salt, di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride. Hydrolysis of the NaCNBH₃ reaction mixture produces the free amine, di(N-(ferrocenylmethyl))-N-methylamine. Thermolysis of di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride in refluxing tetrahydrofuran converts it to the cyanoborane adduct, di(N-ferrocenylmethyl)-N-methylamine–cyanoborane, with elimination of H₂. The new compounds are fully characterized by using spectroscopic and physical methods, including X-ray crystal structure determinations of di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride, di(N-(ferrocenylmethyl))-N-methylamine, and di(N-(ferrocenylmethyl))-N-methylamine–cyanoborane.