Reactions of Imidazoles with Electrophilic Metal Alkyl Complexes

Abstract

The C−C coupling of two molecules of 1-methylbenzimidazole was effected by neutral yttrium and lutetium benzyl complexes supported by a 1,1′-ferrocenylene-diamide ligand. This transformation involves the C−H activation and coupling of one η2(N,C)-imidazolyl fragment with a coordinated 1-methylbenzimidazole ligand. The coupled product can be transformed into a mono- or dinuclear product, in which one of the imidazole rings is cleaved. Variable-temperature 1H and 2H NMR spectroscopic data support the reversibility of the C−C coupling event and explain the formation of the dinuclear product.

Yttrium-Alkyl Complexes Supported by a Ferrocene-Based Phosphinimine Ligand

“…[14][15][16] Our group has studied extensively the reactivity of group 3 metals and uranium alkyl complexes supported by diamide ligands towards heterocyclic aromatic compounds. [17][18] Benzyl complexes were found to ring open 1-methylimidazoles, [19][20][21][22][23] effect C-C coupling of pyridines, [24][25] and alkyl transfer to isoquinoline. [26][27] In those cases, the ligand framework was a ferrocenediamide that could support a weak donor-acceptor interaction between the metal in the ligand.…”

Synthesis of symmetrically and unsymmetrically 3,5-dimethylbenzyl-substituted 1,1′-ferrocene diamines

“…Characterization by 1 H and 13 C NMR spectroscopy indicates that the amine proton peaks of fc(NHXy) 2 (1) appear more downfield than those of the previously reported fc(NHSi t BuMe 2 ) 2 . Further variations from 1 led to fc(NXy 2 ) 2 (2) and fc(NHXy)(NXy 2 ) (3), while reactions carried out from fc(NH 2 ) 2 led to the formation of fc(NH 2 )(NHXy) 4.…”

Modification of Yttrium Silyl‐Bridged Amide Alkyl Complexes through Si−H/C−H Cross‐Dehydrocoupling of Silanes with a Silylamino Ligand: Synthesis, Reactivity, and Mechanism

“…The double-bondc haracter of the N8À C34 bond indicates that C34 is an sp 2 -hybridized carbon atom. [21] These results reveal that the formationo f6 arises from the SiÀH/CÀHc ross-dehydrocouplingr eactiono f1 -methylbenzimidzole with 4a.…”

“…Complex 6 did not further react with excess 1methylbenzimidazole under the same or harsh conditions, which might be attributable to the N-CH 3 substituent hindering access by af urther 1-methylbenzimidazole. [21] Thus, the formation of 6 providesi ndirect evidence for the mechanism for the formation of 5.…”