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Alkenyl Group

The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

Masayuki Hoshi – 1st expert on this subject based on the ideXlab platform

  • preparation of e 1 Alkenylboronic acid pinacol esters via transfer of Alkenyl Group from boron to boron
    Synthesis, 2004
    Co-Authors: Kazuya Shirakawa, Akira Arase, Masayuki Hoshi

    Abstract:

    Two synthetic routes to (E)-1-Alkenylboronic acid pinacol esters 3 were investigated. Hydroboration of 1-alkynes I with 1,3,2-benzodioxaborole (catecholborane), in situ generated by the reaction of BH 3 in THF with catechol, proceeded in the presence of a catalytic amount of dicyclohexylborane in THF at room temperature to give the corresponding (E)-1-Alkenylboronic acid catechol esters 2. Treatment of the resultant esters 2 with 2,3-dimethyl-2,3-butanediol (pinacol) easily afforded the desired products 3, which are insensitive to air, moisture and chromatography, in good to high overall yields. The sequential reaction is a highly efficient route to 3 from BH 3 in THF in a one-pot manner. Alternatively, hydroboration of 1 with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (pinacolborane) was achieved in the presence of a catalytic amount of dicyclohexylborane at room temperature under neat conditions to afford the corresponding products 3 directly in good to excellent yields. This route is extremely efficient and environmentally benign from the viewpoints of making good use of pinacolborane and of using no solvent, and is capable of using a variety of alkynes 1 including functionalized ones such as HCCCH 2 Cl and HCCCH 2 OTHP.

  • Stereoselective dehalogenation of (Z)-1-halo-1-Alkenyldialkylborane with tributyltin hydride: The behavior of tributyltin hydride as a hydride donor
    Tetrahedron Letters, 1997
    Co-Authors: Masayuki Hoshi, Kimitomo Takahata, Akira Arase

    Abstract:

    Abstract The reaction of (Z)-1-halo-1-Alkenyldialkylborane (1) with tributyltin hydride (n-Bu3SnH) at 0 °C or room temperature results in reductive removal of the halogen atom to afford (E)- or (Z)-1-Alkenyldialkylborane whose stereochemistry depends on the dialkylboryl Group and the Alkenyl Group of 1.

Akira Arase – 2nd expert on this subject based on the ideXlab platform

  • preparation of e 1 Alkenylboronic acid pinacol esters via transfer of Alkenyl Group from boron to boron
    Synthesis, 2004
    Co-Authors: Kazuya Shirakawa, Akira Arase, Masayuki Hoshi

    Abstract:

    Two synthetic routes to (E)-1-Alkenylboronic acid pinacol esters 3 were investigated. Hydroboration of 1-alkynes I with 1,3,2-benzodioxaborole (catecholborane), in situ generated by the reaction of BH 3 in THF with catechol, proceeded in the presence of a catalytic amount of dicyclohexylborane in THF at room temperature to give the corresponding (E)-1-Alkenylboronic acid catechol esters 2. Treatment of the resultant esters 2 with 2,3-dimethyl-2,3-butanediol (pinacol) easily afforded the desired products 3, which are insensitive to air, moisture and chromatography, in good to high overall yields. The sequential reaction is a highly efficient route to 3 from BH 3 in THF in a one-pot manner. Alternatively, hydroboration of 1 with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (pinacolborane) was achieved in the presence of a catalytic amount of dicyclohexylborane at room temperature under neat conditions to afford the corresponding products 3 directly in good to excellent yields. This route is extremely efficient and environmentally benign from the viewpoints of making good use of pinacolborane and of using no solvent, and is capable of using a variety of alkynes 1 including functionalized ones such as HCCCH 2 Cl and HCCCH 2 OTHP.

  • Stereoselective dehalogenation of (Z)-1-halo-1-Alkenyldialkylborane with tributyltin hydride: The behavior of tributyltin hydride as a hydride donor
    Tetrahedron Letters, 1997
    Co-Authors: Masayuki Hoshi, Kimitomo Takahata, Akira Arase

    Abstract:

    Abstract The reaction of (Z)-1-halo-1-Alkenyldialkylborane (1) with tributyltin hydride (n-Bu3SnH) at 0 °C or room temperature results in reductive removal of the halogen atom to afford (E)- or (Z)-1-Alkenyldialkylborane whose stereochemistry depends on the dialkylboryl Group and the Alkenyl Group of 1.

Susumu Takada – 3rd expert on this subject based on the ideXlab platform

  • intermolecular transfer of an Alkenyl Group in enamines application to synthesis of b fused pyridines
    Tetrahedron Letters, 1996
    Co-Authors: Makoto Adachi, Takashi Sasatani, Nobuo Chomei, Susumu Takada

    Abstract:

    Abstract A novel intermolecular Alkenyl transfer of enamines was developed for the preparation of cycloAlkenylaminomethyleneoxazolones, which were thermally cyclized to [ b ]-fused pyridines in good yields. The functional manipulation of the pyridines provided versatile precursors for further annulation to tricyclic ring systems.