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A facile route to old and new cyclophanes via self-assembly and capture.

Collins MS, Carnes ME, Nell BP, Zakharov LN, Johnson DW - Nat Commun (2016)

Bottom Line: Herein, we demonstrate a new self-assembly route to a variety of discrete cyclic and caged disulfide structures, which can then be kinetically captured upon sulfur extrusion at room temperature to give a diversity of new thioether (hetera)cyclophanes in high yield.In addition to the synthesis of novel macrocycles (dimers through hexamers), this process provides an improved route to a known macrobicyclic trithiacyclophane.This technique also enables the facile isolation of a tetrahedral macrotricyclic tetrathiacyclophane in two steps at an ambient temperature.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry and the Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, USA.

ABSTRACT
Cyclophanes are a venerable class of macrocyclic and/or cage compounds that often feature high strain, unusual conformations and quite surprising properties, many of which are legendary in physical organic chemistry. However, the discovery of new, diverse cyclophanes and derivatives has been hindered by syntheses that are traditionally low-yielding, requiring long reaction times, laborious purification steps and often extreme conditions. Herein, we demonstrate a new self-assembly route to a variety of discrete cyclic and caged disulfide structures, which can then be kinetically captured upon sulfur extrusion at room temperature to give a diversity of new thioether (hetera)cyclophanes in high yield. In addition to the synthesis of novel macrocycles (dimers through hexamers), this process provides an improved route to a known macrobicyclic trithiacyclophane. This technique also enables the facile isolation of a tetrahedral macrotricyclic tetrathiacyclophane in two steps at an ambient temperature.

No MeSH data available.


Related in: MedlinePlus

Synthesis and crystal structure of a thiatetrohedrophane.Desulfurization (a) of L34 gives tetrathioether [34]tetrahedrophane 5 (6 mol HMPT). Single-crystal X-ray structure representation of thiatetrahedrophane 5 (b); all thermal ellipsoids at 50%. Hydrogen atoms and solvents of crystallization have been omitted for clarity.
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f4: Synthesis and crystal structure of a thiatetrohedrophane.Desulfurization (a) of L34 gives tetrathioether [34]tetrahedrophane 5 (6 mol HMPT). Single-crystal X-ray structure representation of thiatetrahedrophane 5 (b); all thermal ellipsoids at 50%. Hydrogen atoms and solvents of crystallization have been omitted for clarity.

Mentions: Encouraged by the success of sulfur extrusion on the trithioether dimer, we sought to perform sulfur extrusion on the hexadisulfide tetrahedron L34. This would require the extrusion of six sulfur atoms (one on each edge) of the distorted tetrahedron—representing a total of 24 bonds broken/formed in this single step—to proceed with no polymerization and in high yield for each extrusion. We were delighted to discover that sulfur extrusion of all six disulfides to form a tetrahedral hexathioether ‘tetrahedrophane' 5, proceeds by desulfurization with HMPT at an ambient temperature in 4 h in 94% yield (Fig. 4)424344. To the best of our knowledge, this hexathioether assembly is unknown; for related concave spheriphanes, our method reduces an eight-step synthesis to two steps45. The formation of hexathioether 5 was confirmed by 1H NMR spectroscopy, exhibiting time-averaged tetrahedral symmetry in CDCl3 (Supplementary Figs 9 and 10), and single-crystal X-ray diffraction (Fig. 4b). The loss of six sulfur atoms decreases the size of the cyclic structure only slightly and the aromatic and methylene singlets display small, yet expected upfield shifts relative to the disulfide analogue in CDCl3.


A facile route to old and new cyclophanes via self-assembly and capture.

Collins MS, Carnes ME, Nell BP, Zakharov LN, Johnson DW - Nat Commun (2016)

Synthesis and crystal structure of a thiatetrohedrophane.Desulfurization (a) of L34 gives tetrathioether [34]tetrahedrophane 5 (6 mol HMPT). Single-crystal X-ray structure representation of thiatetrahedrophane 5 (b); all thermal ellipsoids at 50%. Hydrogen atoms and solvents of crystallization have been omitted for clarity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4821999&req=5

f4: Synthesis and crystal structure of a thiatetrohedrophane.Desulfurization (a) of L34 gives tetrathioether [34]tetrahedrophane 5 (6 mol HMPT). Single-crystal X-ray structure representation of thiatetrahedrophane 5 (b); all thermal ellipsoids at 50%. Hydrogen atoms and solvents of crystallization have been omitted for clarity.
Mentions: Encouraged by the success of sulfur extrusion on the trithioether dimer, we sought to perform sulfur extrusion on the hexadisulfide tetrahedron L34. This would require the extrusion of six sulfur atoms (one on each edge) of the distorted tetrahedron—representing a total of 24 bonds broken/formed in this single step—to proceed with no polymerization and in high yield for each extrusion. We were delighted to discover that sulfur extrusion of all six disulfides to form a tetrahedral hexathioether ‘tetrahedrophane' 5, proceeds by desulfurization with HMPT at an ambient temperature in 4 h in 94% yield (Fig. 4)424344. To the best of our knowledge, this hexathioether assembly is unknown; for related concave spheriphanes, our method reduces an eight-step synthesis to two steps45. The formation of hexathioether 5 was confirmed by 1H NMR spectroscopy, exhibiting time-averaged tetrahedral symmetry in CDCl3 (Supplementary Figs 9 and 10), and single-crystal X-ray diffraction (Fig. 4b). The loss of six sulfur atoms decreases the size of the cyclic structure only slightly and the aromatic and methylene singlets display small, yet expected upfield shifts relative to the disulfide analogue in CDCl3.

Bottom Line: Herein, we demonstrate a new self-assembly route to a variety of discrete cyclic and caged disulfide structures, which can then be kinetically captured upon sulfur extrusion at room temperature to give a diversity of new thioether (hetera)cyclophanes in high yield.In addition to the synthesis of novel macrocycles (dimers through hexamers), this process provides an improved route to a known macrobicyclic trithiacyclophane.This technique also enables the facile isolation of a tetrahedral macrotricyclic tetrathiacyclophane in two steps at an ambient temperature.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry and the Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1253, USA.

ABSTRACT
Cyclophanes are a venerable class of macrocyclic and/or cage compounds that often feature high strain, unusual conformations and quite surprising properties, many of which are legendary in physical organic chemistry. However, the discovery of new, diverse cyclophanes and derivatives has been hindered by syntheses that are traditionally low-yielding, requiring long reaction times, laborious purification steps and often extreme conditions. Herein, we demonstrate a new self-assembly route to a variety of discrete cyclic and caged disulfide structures, which can then be kinetically captured upon sulfur extrusion at room temperature to give a diversity of new thioether (hetera)cyclophanes in high yield. In addition to the synthesis of novel macrocycles (dimers through hexamers), this process provides an improved route to a known macrobicyclic trithiacyclophane. This technique also enables the facile isolation of a tetrahedral macrotricyclic tetrathiacyclophane in two steps at an ambient temperature.

No MeSH data available.


Related in: MedlinePlus