Research Overview

日本語（in Japanese）

Double-Stranded Helical Polymers and Oligomers with Specific Functions

　Apart from numerous variations of single-stranded helical polymers and oligomers, the molecular design for double-stranded helical polymers is limited, in spite of the natural model, the double-helical DNA. We have developed a modular strategy to construct complementary double helices stabilized by salt bridges with crescent-shaped m-terphenyl backbones. A series of double helices composed of different sequences and chain-lengths have also been synthesized. A complementary double-helix dimer composed of achiral strands bridged by achiral diphosphines was also prepared enantioselectively, by taking full advantage of the “helicity induction and memory” effect, which accommodated metal ions and the Cu(I) complex catalyzed the asymmetric cyclopropanation reaction. The chiral space generated by the double helical structure is indispensable for the high enantioselectivity (up to 85% ee), thus providing a promising and conceptually new strategy in the broad fields of supramolecular catalysis with a unique double helical structure. We also serendipitously found that oligoresorcinols self-assemble into well-defined double helices resulting from interstrand aromatic stacking in water, which bound cyclic and linear oligosaccharides in water to form rotaxanes and hetero-double helices, respectively. Since specific recognition of oligosaccharides in water is still considered underdeveloped in spite of the well-established synthetic receptors for mono- and disaccharides, these results provide a new conceptual approach to the saccharide recognition in water. The mechanism of double-helix formation of oligoresorcinols is fully elucidated by means of NMR, CD, X-ray, MS, and calculations. In addition, we recently developed an optically active helicate consisting of two tetraphenol strands bridged by two spiroborate groups sandwiches a sodium ion. On removal of the central sodium ion through addition of a cryptand [2.2.1] in solution, the double helicate extends. This anisotropic spring-like extension-contraction motion is reversibly triggered by the successive addition and removal of sodium ions in solution with maintaining its one-handedness, leading to an ion-triggered molecular spring.

  • 　　Development of Innovative Chiral Materials Based on Controlled Helical Nano-Space（PDF, 1.3 MB)
    One-Handed Double and Triple Helices

    Related Important Papers

    1. Y. Tanaka, H. Katagiri, Y. Furusho, E. Yashima, Angew. Chem., Int. Ed., 44, 3867-3870 (2005).
    2. H. Katagiri, T. Miyagawa, Y. Furusho, E. Yashima, Angew. Chem., Int. Ed., 45, 1741-1744 (2006).
    3. M. Ikeda, Y. Furusho, K. Okoshi, S. Tanahara, K. Maeda, S. Nishino, T. Mori, E. Yashima, Angew. Chem., Int. Ed., 45, 6491-6495 (2006).
    4. M. Ikeda, Y. Tanaka, T. Hasegawa, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 128, 6806-6807 (2006).
    5. H. Goto, H. Katagiri, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 128, 7176-7178 (2006).
    6. H. Goto, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 129, 109-112 (2007).
    7. H. Goto, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 129, 9168-9174 (2007).
    8. H. Katagiri, Y. Tanaka, Y. Furusho, E. Yashima, Angew. Chem., Int. Ed., 46, 2435-2439 (2007).
    9. T. Hasegawa, H. Goto, Y. Furusho, H. Katagiri, E. Yashima, Angew. Chem., Int. Ed., 46, 5885-5888 (2007).
    10. Y. Furusho, Y. Tanaka, T. Maeda, M. Ikeda, E. Yashima, Chem. Commun., 3174-3176 (2007).
    11. T. Maeda, Y. Furusho, S.-i. Sakurai, J. Kumaki, K. Okoshi, E. Yashima, J. Am. Chem. Soc., 130, 7938-7945 (2008).
    12. H. Ito, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 130, 14008-14015 (2008).
    13. H. Goto, Y. Furusho, K. Miwa, E. Yashima, J. Am. Chem. Soc., 131, 4710-4719 (2009).
    14. Y. Nakatani, Y. Furusho, E. Yashima, Angew. Chem., Int. Ed., 49, 5463-5467 (2010).
    15. H. Ito, M. Ikeda, T. Hasegawa, Y. Furusho, E. Yashima, J. Am. Chem. Soc., 133, 3419-3432 (2011).
    16. K. Miwa, Y. Furusho, E. Yashima, Nature Chem., 2, 444-449 (2010).
    17. N. Ousaka, Y. Takeyama, H. Iida, E. Yashima, Nature Chem., 3, 856-861 (2011).

    Detailed Information