title: Diastereo- and enantioselective synthesis of organometallic bis(helicene)s by a combination of C-H activation and dynamic isomerization.
abstract: Homochiral and heterochiral cis-bis-cycloplatinated-[6]helicene derivatives 1b(1,2), as representative examples of platina[6]helicenes that share a common platinum center, have been prepared. A diastereo- and enantioselective synthesis, which combines CH activation and dynamic isomerization from heterochiral structure 1b(2) into homochiral structure 1b(1), is also described. Overall, this isomerization process results in the transfer of chiral information from one helicene moiety to the other one. The chiroptical properties of homochiral (P)- and (M)-1b(1) were greatly modified upon oxidation into their corresponding (P)- and (M)-diiodo-Pt(IV) complexes (5). The changes were also analyzed by performing theoretical calculations. C-H activation in the synthesis of organometallic helicenes is further demonstrated by the preparation of cis-bis-cycloplatinated-[8]helicene 1c.
authors.affiliation: Sciences Chimiques de Rennes, UMR 6226, Institut de Physique de Rennes, UMR 6251, CNRS Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex (France).
authors.forename: Chengshuo
authors.initials: C
authors.lastname: Shen
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Anger
authors.forename: Monika
authors.initials: M
authors.lastname: Srebro
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanthuyne
authors.forename: Loïc
authors.initials: L
authors.lastname: Toupet
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.forename: Jochen
authors.initials: J
authors.lastname: Autschbach
authors.forename: Régis
authors.initials: R
authors.lastname: Réau
authors.forename: Jeanne
authors.initials: J
authors.lastname: Crassous
keywords: CH activation; chiroptical properties; density functional calculations; helicenes; isomerization