Crown Ether-Substituted Indene and 3,4-Dimethylcyclopentadiene

Article abstract of DOI:10.1021/jo00076a025

Several indene and cyclopentadiene derivatives have been synthesized, which are substituted with crown ethers, thereby creating ligands whose heterotopic faces have the ability to function as ligands in both organometallic and coordination chemistry.The syntheses of mono- and bis-N-3-indenylpropyl-substituted aza-12-crown-4 4, aza-15-crown-5 5, and diaza-18-crown-6 6 ether compounds are described.However it was not possible to isolate stable η⁵-bound metal complexes with 4, 5, or 6.In an alternative approach 1-(2-aminoethyl)-3,4-dimethyl-cyclopenta-1,3-diene (9) has been prepared from 3,4-dimethylcyclopent-2-enone (7) via Knoevenagel condensation, followed by reduction of the α,β,γ,δ-unsaturated nitrile 8 with LiAlH4/AlCl3.Cyclization of 9 produced the first example of crown ether-substituted cyclopentadienes, N-<2-(3,4-dimethylcyclopenta-1,3-dienyl)ethyl>aza-12-C-4 (10) (12-C-4-HCp''), and as the result of a 2+2 addition, N,N'-bis<2-(3,4-dimethylcyclopenta-1,3-dienyl)ethyl>-1,13-diaza-24-crown-8 (11) (24-C-8-HCp''2).Reaction of 10 with NaH, (CO)3W(CH3CN)3, and CH3I affords the η⁵-bound complex (12-C-4-Cp'')W(CO)3CH3 (12), which in turn can complex Na(+) to give 13 (=(12)2*Na(+)BPh4(-)).