title: Synthesis of Naphthylpyridines from Unsymmetrical Naphthylheptadiynes and the Configurational Stability of the Biaryl Axis.
abstract: A series of different unsymmetrically substituted naphthyl-based diynes were synthesized. These substrates formed the foundation for the assembly of novel biaryls containing pyridine moieties with differently substituted five-membered rings in the backbone of the newly formed heterobiaryl system. The key step for their efficient construction was the photo- and cobalt-catalyzed [2 + 2 + 2] cycloaddition reaction between the corresponding naphthyldiyne and aceto- or benzonitrile. The heterobiaryl products have been isolated and investigated with respect to the configurational stability of their biaryl axis using dynamic chiral HPLC; subtle effects of the substitution pattern on the stability of the axis were observed. For several compounds the activation barriers (ΔG(‡)) of racemization were determined. Suitable substitution of the five-membered ring backbone exemplarily allowed the Co-catalyzed enantioselective cyclization to yield the enantiomerically enriched heterobiaryl.
authors.affiliation: Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT) , Albert-Einstein-Straße 29a, D-18059 Rostock, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Fischer
authors.affiliation: Organisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Siegle
authors.affiliation: CreativeQuantum GmbH (Adlershof) , Wegedornstrasse 32, D-12524 Berlin, Germany.
authors.forename: Marek
authors.initials: M
authors.lastname: Checinski
authors.affiliation: Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT) , Albert-Einstein-Straße 29a, D-18059 Rostock, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Fischer
authors.affiliation: Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT) , Albert-Einstein-Straße 29a, D-18059 Rostock, Germany.
authors.forename: Karolin
authors.initials: K
authors.lastname: Kral
authors.affiliation: Institut für Biochemie, Universität Greifswald , Felix-Hausdorff-Straße 4, D-17487 Greifswald, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Thede
authors.affiliation: Organisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Trapp
authors.affiliation: Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT) , Albert-Einstein-Straße 29a, D-18059 Rostock, Germany.|Johannes Kepler Universität Linz , Institut für Katalyse, Altenberger Straße 69, A-4040 Linz, Austria.
authors.forename: Marko
authors.initials: M
authors.lastname: Hapke