Premium
Chiral Photoresponsive Tetrathiazoles That Provide Snapshots of Folding States
Author(s) -
Nakashima Takuya,
Yamamoto Kyohei,
Kimura Yuka,
Kawai Tsuyoshi
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302564
Subject(s) - folding (dsp implementation) , chemistry , stacking , chirality (physics) , intramolecular force , stereochemistry , helix (gastropod) , diastereomer , vicinal , crystallography , physics , ecology , chiral symmetry breaking , organic chemistry , quantum mechanics , quark , snail , nambu–jona lasinio model , electrical engineering , biology , engineering
Abstract Herein, we designed chiral photoresponsive tetra(2‐phenylthiazole)s, which induce a diastereoselective 6π‐electrocyclization reaction in a helically folded structure to freeze the conformational interconversions. The folding conformation with one helical turn of tetra(2‐phenylthiazole)s was supported by multiple intramolecular noncovalent interactions including vicinal S⋅⋅⋅N interheteroatom interactions and CH–π and π–π stacking interactions between nonadjacent units, as found in X‐ray crystal structures as well as quantum chemical calculations. The introduction of a chiral group at both ends of tetra(2‐phenylthiazole) dictates the preferential folding into a one‐handed helix conformation by the simultaneous operation of S⋅⋅⋅O and multiple CH–π interactions that involve the chiral end groups. Since the tetra(2‐phenylthiazole)s possess two equivalent photoreactive 6π‐electron systems and the folded conformation is suitable for photoinduced electrocyclization reaction, they undergo a photocyclization reaction in a stereoselective manner to memorize the chirality of the helix in a resulting diastereomeric closed form.