title: Dynamic Chirality Control of tropos DPCB-digold Skeleton by Chiral Binaphthyldicarboxylate.
abstract: The planar 3,4-diphosphinidenecyclobutene (DPCB) can be remarkably twisted into a C2 -type helical structure by dual coordination of a AuCl moiety. A prompt chirality control of the twisted DPCB skeleton ligated by the digold units affords the enantiopure structure by exchanging the chloride ligands for chiral [1,1'-binaphthalene]-2,2'-dicarboxylate. The chirality of the diaurated 2,2'-bis(diphenylphosphanyl)-1,1'-biphenyl (BIPHEP) system can be controlled prior to that of DPCB. Mixing of a DPCB-bis(chlorogold) complex with the chiral silver salt dynamically leads to a single diastereomer, which was characterized by the (31) P NMR spectrum and the CD couplet patterns in the visible (DPCB) area. The absolute configuration of the singly induced helical structure was assigned by the theoretical CD spectra determined by TD-DFT calculations. Intramolecular alkoxycyclization of hexa-4,5-dien-1-ol catalyzed by the asymmetric DPCB-digold structure were also attempted.
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan. ito.s.ao@m.titech.ac.jp.
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Ito
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Nanko
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Shinozaki
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kojima
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan.
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Aikawa
authors.affiliation: Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8552, Japan. mikami.k.ab@m.titech.ac.jp.
authors.forename: Koichi
authors.initials: K
authors.lastname: Mikami
keywords: atropisomerism; circular dichroism; gold; helical structures; phosphaalkenes