Rotational isomerism in 2,4,6-tri-tert-butylanilides

Ototake, Nobutaka; Takahashi, Isao; Tsukagoshi, Shiori; Maeda, Tatsuki; Kitagawa, Osamu

doi:10.1016/j.tet.2012.11.096

Cited by 1 publication

(1 citation statement)

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“…Close values of the conformation states energy minima of 3 suggests that the cluster can exist not only in the conformation corresponding to the global energy minimum, but also in the conformation of the local energy minima arising under the corresponding kinetic conditions. Formation of one or two stable rotamers from several congeners is quite common in various reactions [19–24] . Our multiple attempts to crystallize other conformers of 3 were unsuccessful.…”

Section: Resultsmentioning

confidence: 99%

Unusual Synthesis of Triosmium Carbene Clusters by Tandem Activation of Chlorohydrocarbons and Heterocyclic Amines

et al. 2021

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Reactions of the [Os3H2(CO)10] cluster complex (1) with six‐membered heterocyclic amines (morpholine, thiomorpholine, piperidine) and halohydrocarbons (CH2Cl2, ClHC=CHCl, CH2=CCl2) at ∼25 °C have been studied. Two main types of products are formed in all studied reactions. One product is carbene cluster [Os3(μ−H)(μ−Cl){η1−C(CH3)N(CH2CH2)2X}(CO)9] (X=O, S, CH2) (3, 3 a and 3 b). Second product is cluster containing enamine ligand [Os3(μ−H){μ‐CH=CHN(C2CH2)2Х)}2(CO)10] (X=O, S, CH2) (2, 2 a and 2 b). The carbene ligand is assembled on a cluster, from three organic molecules, thus representing the first example of carbene ligands formed in this way. Clusters with carbene ligand exist as two stable isomers (rotamers hindered towards the Os−C bond), as confirmed by NMR studies and conformational analysis. We have found that in reactions of cluster 1 with acyclic amines containing an oxygen atom in γ‐position (likely morpholine in CH2Cl2), only complexes with bridging enamine ligands are formed. Compounds 2 a, 2 b, 3 and 3 b are characterized by single‐crystal X‐ray diffraction.

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Section: Resultsmentioning

confidence: 99%