Novel thiophenophan-1-enes, which are composed of a dithienylethene unit and a chiral bridge, were synthesized and obtained as optically-active single diastereomers. Upon UV irradiation, the open-form isomers afforded single diastereomers of the closed form in 100% diastereo-excess, indicating that this system undergoes a fully diastereospecific photochromic reaction.
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http://dx.doi.org/10.1039/c0cc00580k | DOI Listing |
Angew Chem Int Ed Engl
October 2013
Chemistry Department, University of Hawaii at Manoa, 2545 The Mall, Honolulu, HI 96822 (USA).
No vacancy: Fully substituted dienones that are highly polarized by a vinylogous carbonate group were found to undergo a remarkably rapid and diastereospecific Nazarov cyclization that led to cyclopentenones with vicinal all-carbon-atom quaternary centers (see example; SEM=2-(trimethylsilyl)ethoxymethyl, Tf=trifluoromethanesulfonyl).
View Article and Find Full Text PDFChemistry
December 2012
Laboratoire Hétéroéléments et Coordination, Ecole Polytechnique, CNRS, Route de Saclay, 91120 Palaiseau, France.
J Org Chem
August 2012
Program of Chemical Biology, Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, SE-75123 Uppsala, Sweden.
Two free-radical cyclization reactions with the radical at the chiral C4 of the pentose sugar and the intramolecularly C1-tethered olefin (on radical precursors 8 and 17) gave a new diastereospecific C4-C8 bond in dimethylbicyclo[2.2.1]heptane 9, whereas the new C4-C7 bond in 7-methyl-2-oxabicyclo[2.
View Article and Find Full Text PDFChemistry
July 2012
Department of Chemistry and Applied Chemistry, Saga University, Honjo 1, Saga 840-8502, Japan.
Thiophenophan-1-enes with chiral polyether bridges were prepared and their diastereospecific photochromic reactions were studied. The coupling reaction of substituted dithienylethenes and various chiral synthons afforded thiophenophan-1-enes, namely, bridged dithienylethenes, as single enantiomers without optical resolution, thus indicating that these reactions occurred diastereoselectively. Upon UV irradiation, each optically active thiophenophan-1-ene isomerized to the corresponding enantiomer of the closed form and returned to the initial enantiomer of the open form upon visible irradiation.
View Article and Find Full Text PDFChem Commun (Camb)
June 2010
Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502, Japan.
Novel thiophenophan-1-enes, which are composed of a dithienylethene unit and a chiral bridge, were synthesized and obtained as optically-active single diastereomers. Upon UV irradiation, the open-form isomers afforded single diastereomers of the closed form in 100% diastereo-excess, indicating that this system undergoes a fully diastereospecific photochromic reaction.
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