Synthesis and stereoisomerism of [n]cyclo-2,9-phenanthrenylene congeners possessing alternating E/Z- and R/S-biaryl linkages
| Autor: | Sota Sato, Hiroyuki Isobe, Yong Yang, Yuki Nanjo |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Atropisomer
010405 organic chemistry Stereochemistry Dimer Organic Chemistry Stereoisomerism 010402 general chemistry 01 natural sciences Biochemistry 0104 chemical sciences Separable space chemistry.chemical_compound chemistry Phenanthrene derivative Axial chirality Physical and Theoretical Chemistry Chirality (chemistry) |
| Zdroj: | Organic & Biomolecular Chemistry. 18:4949-4955 |
| ISSN: | 1477-0539 1477-0520 |
| DOI: | 10.1039/d0ob01064b |
| Popis: | The synthesis and cyclostereoisomerism of [n]cyclo-2,9-phenanthrenylenes ([n]CPhen2,9, n = 4, 6 and 8), possessing hybrid E/Z- and R/S-biaryl linkages, were elaborated. The dimer of a phenanthrene derivative was used as a starting material and underwent Ni-mediated Yamamoto-type coupling to afford [6]CPhen2,9 as a major cyclic product, as well as [4]CPhen2,9 and [8]CPhen2,9 as minor products. The stereoisomers of [n]CPhen2,9 were isolated and characterized, and the number of stereoisomers indicated that E/Z linkages did not provide any experimentally separable isomers, whereas the chirality in [n]CPhen2,9 originated from the intrinsic axial chirality at constrained R/S linkages. Theoretical calculations predicted that the 2,2'-linkages in [n]CPhen2,9 adopted a fixed Z- or E-configuration, which suggested a novel type of dynamics of atropisomerism in contrast to the reported rigid or flexible behavior. This study enriches our understanding of the stereochemical features of E/Z linkages in aromatic macrocycles. |
| Databáze: | OpenAIRE |
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