title: Boron-mediated sequential alkyne insertion and C-C coupling reactions affording extended π-conjugated molecules.
abstract: C-C bond coupling reactions illustrate the wealth of organic transformations, which are usually mediated by organotransition metal complexes. Here, we show that a borafluorene with a B-Cl moiety can mediate sequential alkyne insertion (1,2-carboboration) and deborylation/Csp(2)-Csp(2) coupling reactions, leading to aromatic molecules. The first step, which affords a borepin derivative, proceeds very efficiently between the borafluorene and various alkynes by simply mixing these two components. The second step is triggered by a one-electron oxidation of the borepin derivative, which results in the formation of a phenanthrene framework. When an excess amount of oxidant is used in the second step, the phenanthrene derivatives can be further transformed in situ to afford dibenzo[g,p]chrysene derivatives. The results presented herein will substantially expand the understanding of main group chemistry and provide a powerful synthetic tool for the construction of a wide variety of extended π-conjugated systems.
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Yoshiaki
authors: 0000-0001-8437-1965
authors: Y
authors: Shoji
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Naoki
authors: N
authors: Tanaka
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Sho
authors: S
authors: Muranaka
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Naoki
authors: N
authors: Shigeno
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Haruka
authors: H
authors: Sugiyama
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Kumiko
authors: K
authors: Takenouchi
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Fatin
authors: F
authors: Hajjaj
authors: Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors: Takanori
authors: T
authors: Fukushima