The structural and stereogenic properties of pentaerythritoxy-bridged cyclotriphosphazene derivatives: spiro–spiro, spiro–ansa and ansa–ansa isomers
作者:Simon J. Coles、David B. Davies、Robert J. Eaton、Michael B. Hursthouse、Adem Kılıç、Robert A. Shaw、Aylin Uslu
DOI:10.1039/b512854d
日期:——
derivatives linked spiro–spiro, spiro–ansa and ansa–ansa. The structures and stereogenic properties of the products were characterised by X-ray crystallography and 31P NMR spectroscopy on addition of the chiral solvating agent, (S)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol. Molecules with spiro–spiro and spiro–ansa bridged gem-disubstituted cyclophosphazenes [R = Ph, NHBut or (OCH2CF2CF2CH2O)0.5] are found to
New Synthetic Approach to Molecular Rods Using Cyclophosphazene-Based Oligospiranes
作者:Serap Beşli、Ceylan Mutlu Balcı、Aylin Uslu、Christopher W. Allen
DOI:10.1021/acs.inorgchem.7b01715
日期:2017.8.21
A syntheticapproach was developed to prepare a new type of highly functionalized inorganic–organic heterocyclic molecular rod (3a and 3b) consisting of cyclophosphazene and carbocyclic units. Single-crystal X-ray diffraction analysis of 3a revealed that the molecular length was ca. 2.5 nm. The products of this high-yield process have the potential for derivatization via known phosphazene reactions
Stereogenic properties of spiranes combined with four equivalent conventional centres of chirality
作者:Simon J. Coles、David B. Davies、Robert J. Eaton、Michael B. Hursthouse、Adem Kılıç、Robert A. Shaw、Aylin Uslu
DOI:10.1039/b700464h
日期:——
Derivatives of the tri-spirane pentaerythritoxy-cyclophosphazene compound, 1, have been used to investigate the stereogenic properties of spiranes combined with four equivalent conventional centres of chirality. In compound 1 the two inner rings are carbocyclic and symmetrical and the two outer rings are cyclotriphosphazenes substituted in different positions to provide the conventional centres of chirality. The case of combining spiranes with four equivalent centres of chirality has been investigated by the reaction of 1 with dimethylamine in a 1 : 8 molar ratio to give four diastereoisomeric products, in which the two cyclophosphazene rings are non-geminally di-substituted in either cis or trans configurations; viz. the cis–cis (2a), cis–trans (2b) and two trans–trans substituted dimethylamine derivatives 2c and 2d. The structure and stereogenic properties of compound 2a (C2 symmetry) have been characterized previously by both X-ray crystallography and 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) and the structures and stereogenic properties of compounds 2b (C1) and 2d (C2) have been similarly characterized in this work. The structure of compound 2c has been characterised by X-ray crystallography and found to be meso with the relatively rare S4 symmetry. The four diastereoisomeric products 2a–2d represent all the possible stereochemical isomers of a spirane combined with four equivalent conventional centres of chirality.
Shaw, Robert A., Phosphorus, Sulfur and Silicon and the Related Elements, 1989, vol. 45, p. 103 - 136
作者:Shaw, Robert A.
DOI:——
日期:——
Stereogenic properties of spiranes combined with one or two equivalent conventional centres of chirality
作者:Simon J. Coles、David B. Davies、Michael B. Hursthouse、Adem Kılıç、Şule Şahin、Robert A. Shaw、Aylin Uslu
DOI:10.1016/j.jorganchem.2007.02.003
日期:2007.6
Derivatives of the tri-spirane pentaerythritoxy-cyclophosphazene compound 1 have been used to investigate the stereogenic properties of spiranes combined with either one or two conventional centres of chirality. In compound 1, the two inner rings are carbocyclic and symmetrical and the two outer rings are cyclotriphosphazenes substituted in different positions to provide the conventional centres of chirality. Reaction of I in a 1:1 molar ratio with the unsymmetrical dinucleophilic reagent, 1,3-aminopropanol, gave the mono-spiro substituted derivative 2, which was shown to exist as a racemate by X-ray crystallography and P-31 NMR spectroscopy on addition of a chiral solvating agent (CSA). Reaction of 1 with 1,3-aminopropanol in a 1:2 molar ratio gave three diastereoisomeric di-mono-spiro products 3a-3c, which were all shown to be racemates using a combination of X-ray crystallography (3a, 3c) and P-31 NMR spectroscopy on addition of a CSA (3b), thus proving the case of the stereogenic properties of spirane molecules combined with two equivalent conventional centres of chirality. It is also shown by quantitative P-31 NMR spectroscopy of the reaction mixture and by isolation of reaction products that the proportions of the diastereoisomers 3a:3b:3c are in approximate ratios of 1:2: 1, respectively, and these results have been rationalised by analysis of the stereogenic properties of the series of reactions 1 -> 2 -> 3. (c) 2007 Elsevier B.V. All rights reserved.