title: Chiral helicenoid diarylethene with large change in specific optical rotation by photochromism.
abstract: A diarylethene possessing one [4]thiaheterohelicene and one benzothiophene, the latter with a chiral methoxymethoxyethyl group on its C-3 position, was proved to work as a switch of specific optical rotation at a wavelength at which both colored and colorless forms have no absorption in solution. The difference of the specific optical rotation was 1300 degrees between the open form and the photostationary state. The specific optical rotation of one of the isolated optically active major colored forms was -4680 degrees. The conversion to the colored form was 64%, and the diastereomeric excess of photocyclization was 47%.
authors.affiliation: Department of Advanced Materials Chemistry, Graduate School of Engineering, Yokohama National University, Hodogaya, Yokohama 240-8501, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Okuyama
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tani
authors.forename: Kentaro
authors.initials: K
authors.lastname: Miyake
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yokoyama