Novel Analogs of Tropolone

New Perspectives for Aminotroponiminates: Coordination Chemistry, Redox Behavior, Cooperativity, and Catalysis

“…After initial reports on the functionalization of the C 7 ligand backbone in the 5‐position via electrophilic aromatic substitution,, this type of reaction has recently been investigated in further detail . Bromination proceeds smoothly and in excellent yields (90 %),, , while other substituents can be introduced only with lower yields of 19–43 % [Scheme , E = Br, I, N 2 Aryl, NO 2 , COMe, C 2 (CN) 3 ] , , . The bromo‐substituted compound 9‐Br can be subjected to nucleophilic aromatic substitution to give 10‐Nu in excellent yields (92–99 %) {Scheme : Nu = SPh, S[3,5‐C 6 H 3 (CF 3 ) 2 ], SePh, TePh; Nu = S(O)Ph with one additional step} .…”

“…Along these lines, the combination of R 1 = sterically demanding aryl group and R 2 = alkyl group can be realized as a substitution pattern in ATI ligands, [11,13] however, the installa-tion of two sterically demanding 2,6-substituted aryl groups has been described as problematic. [16] After initial reports on the functionalization of the C 7 ligand backbone in the 5-position via electrophilic aromatic substitution, [17,18] this type of reaction has recently been investigated in further detail. [19][20][21][22][23] Bromination proceeds smoothly and in excellent yields (90 %), [17,18,[20][21][22] while other substituents can be introduced only with lower yields of 19-43 % [Scheme 3, E = Br, I, N 2 Aryl, NO 2 , COMe, C 2 (CN) 3 ].…”

Solid‐State Structure and Tautomerism of 2‐Aminotroponimines Studied by X‐ray Crystallography and Multinuclear NMR Spectroscopy

“…These authors report a chemical shift for δ 15 N-1/N-9 of 164.8 ppm referenced to external 1.0  aqueous 15 NH 4 Cl, compared with our experimental value of 144.4 ppm using solid 15 NH 4 Cl [in Table 5 4458 due to the difference between solid and aqueous ammonium chloride.…”

“…The 13 C and 15 N NMR spectra of N-phenyl-2-(phenylamino)troponimine (2) had previously been recorded by Jackman et al [21] in deuteriobromoform at 26°C, and values close to those described in this paper were observed. These authors report a chemical shift for δ 15 N-1/N-9 of 164.8 ppm referenced to external 1.0  aqueous 15 NH 4 4458 due to the difference between solid and aqueous ammonium chloride. [22] For the symmetric derivatives 3 (R 1 ϭ R 2 ϭ p-bromophenyl) and 5 (R 1 ϭ R 2 ϭ pyrrol-1-yl), only one signal in the 15 N NMR spectra is also observed.…”

Aminotroponiminates: Impact of the NO2 Functional Group on Coordination, Isomerisation, and Backbone Substitution

“…For aminotroponiminates (ATIs) in particular, reactions aiming at the installation of different types of substituents at the nitrogen atoms [11] and the ligand backbone[ 11c , 12 ] have been developed, and their impact on structure and reactivity has been demonstrated (Figure 1 ). Systematic variations of nitrogen‐bound substituents can be exploited to control the ability of ATI ligands to interact with metal atoms through the π‐electrons of their ligand backbone (Figure 1 a)[ 11h , 13 ] and their catalytic activity in the polymerisation of ϵ‐caprolactone.…”