title: Cobalt-Catalyzed Cross-Benzannulation of Conjugated Enynes and Diynes.
abstract: The [4 + 2] cross-benzannulation of conjugated enynes and diynes under cobalt-catalysis led to 1,2,3-trisubstituted benzene derivatives in good yields. The reaction proceeds smoothly in absolute regiospecific control when symmetrical diynes are applied. Moreover, the use of unsymmetrical diynes was investigated, resulting in the formation of the unprecedented regioisomers as major products, which is in contrast to the results obtained in palladium-catalyzed benzannulation reactions. Also, 4-bromophenyl-substituted starting materials could be applied successfully in the cobalt-catalyzed process, which can be problematic in the palladium-catalyzed counterpart.
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Röse
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
authors.forename: Carmen Carlota Magraner
authors.initials: CC
authors.lastname: Garcia
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Pünner
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Harms
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043 Marburg, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hilt