Insertion, reduction, and carbon-carbon coupling induced by monomeric aluminum hydride compounds bearing substituted pyrrolyl ligands

Che Yu Lin, Chia Fu Tsai, Hsing Jen Chen, Chen Hsiung Hung, Ru Ching Yu, Pei Cheng Kuo, Hon Man Lee, Jui-Hsien Huang

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A monomeric aluminum hydride complex bearing substituted pyrrolyl ligands, AlH[C4H3N(CH2NMe2)2]2 (1), was synthesized and structurally characterized. To further confirm the presence of AI-H bonds, the compound AlD[C4H3N(CH 2NMe2)-2]2 ([D]l) was synthesized by reacting LiAID4 with [C4H4N(CH2NMe 2)-2]. Compound 1 and [D]1 react with phenyl isothiocyanate yielding Al[C4H3N(CH2NMe2)-2] 23-SCHNPh] (2) and Al[C4H 3N(CH2NMe2)-2]2[η-SCDNPh] ([D]2) by insertion. The reactions of 1 with 9-fluorenone and benzophenone generated the unusual aluminum alkoxide complexes 3 and 4, respectively, through intramolecular proton abstraction and C-C coupling. A mechanistic study shows that 9-fluorenone coordinates to [D]l and releases one equivalent of HD followed by C-C coupling and hydride transfer to yield the final product. Reduction of benzil with 1 affords aluminum enediolate complex 5 in moderate yield. Mechanistjfc^tudies also showed that the benzil was inserted into the aluminum hydride bond of [D]l through hydroalumination followed by proton transfer to generate the final product [D]S. All new complexes have been characterized by 'H and 13CNMR spectroscopy and X-ray crystallography.

Original languageEnglish
Pages (from-to)3067-3073
Number of pages7
JournalChemistry - A European Journal
Issue number11
Publication statusPublished - 2006 Apr 3


All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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