title: Controlling the Scholl reaction.
abstract: Guidelines for the application of the Scholl reaction were developed. Labeling experiments demonstrate that the Scholl reaction fails in small, unsubstituted oligophenylenes (e.g., o-terphenyl) due to oligomerization of the products (e.g., triphenylene). Incorporation of suitably placed blocking groups (e.g., t-butyl) suppresses oligomerization. The well-established directing group effects in electrophilic aromatic substitution predict the outcome of Scholl reactions of substituted substrates. Activating o,p-directing groups (e.g., MeO) direct bond formation o,p, either intramolecularly or intermolecularly. Deactivating o,p-directing groups (e.g., Br) also direct bond formation o,p but yields are lower. Deactivating m-directors (e.g., NO2) suppress reaction. MoCl5 and PhI(OOCCF3)2/BF3.Et2O are general and effective reagents for the Scholl oxidation. Calculations (B3LYP/6-31G(d)) predict the Scholl reaction in alkoxyarenes to proceed via arenium cations, not radical cations. Suzuki-Miyaura couplings were used to generate 12 substituted o-terphenyl derivatives.
authors.affiliation: Department of Chemistry, University of Nevada-Reno, Reno, Nevada 89557, USA. king@chem.unr.edu
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: King
authors.forename: Jirí
authors.initials: J
authors.lastname: Kroulík
authors.forename: Charles R
authors.initials: CR
authors.lastname: Robertson
authors.forename: Pawel
authors.initials: P
authors.lastname: Rempala
authors.forename: Cameron L
authors.initials: CL
authors.lastname: Hilton
authors.forename: Justin D
authors.initials: JD
authors.lastname: Korinek
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Gortari