5 research outputs found
Pd-Catalyzed Tandem sp<sup>2</sup>–sp<sup>3</sup> Coupling Reactions of Chiral Stannolanes: An Efficient Preparation of Optically Active Tetrahydrobenz[<i>f</i>]isoindoles
A novel double Migita–Kosugi–Stille coupling reaction with dihydrostannolanes, which are readily available from a radical cascade reaction, was achieved with dihalobenzenes in the presence of a palladium catalyst. Use of unsymmetrical 1-bromo-2-iodobenzene derivatives accomplished the double coupling reaction which gave tetrahydrobenz[<i>f</i>]isoindoles in a regioselective manner
Pd-Catalyzed Tandem sp<sup>2</sup>–sp<sup>3</sup> Coupling Reactions of Chiral Stannolanes: An Efficient Preparation of Optically Active Tetrahydrobenz[<i>f</i>]isoindoles
A novel double Migita–Kosugi–Stille coupling reaction with dihydrostannolanes, which are readily available from a radical cascade reaction, was achieved with dihalobenzenes in the presence of a palladium catalyst. Use of unsymmetrical 1-bromo-2-iodobenzene derivatives accomplished the double coupling reaction which gave tetrahydrobenz[<i>f</i>]isoindoles in a regioselective manner
Pd-Catalyzed Tandem sp<sup>2</sup>–sp<sup>3</sup> Coupling Reactions of Chiral Stannolanes: An Efficient Preparation of Optically Active Tetrahydrobenz[<i>f</i>]isoindoles
A novel double Migita–Kosugi–Stille coupling reaction with dihydrostannolanes, which are readily available from a radical cascade reaction, was achieved with dihalobenzenes in the presence of a palladium catalyst. Use of unsymmetrical 1-bromo-2-iodobenzene derivatives accomplished the double coupling reaction which gave tetrahydrobenz[<i>f</i>]isoindoles in a regioselective manner
Concise Synthesis of 2-Benzazepine Derivatives and Their Biological Activity
2-Benzazepines, which are potentially good candidates
for new drug
therapies to treat skin wounds, were readily prepared from substituted
cinnamylamide via an intramolecular Friedel–Crafts reaction.
With few steps and effective reactions, the procedure enables a rapid
derivatization of 2-benzazepines. Moreover, optically active 4-substituted-2-benzazepines
were prepared from chiral α-substituted cinnamylamides, which
were readily prepared by asymmetric α-alkylation of chiral cinnamyl
oxazolidinone amides. We have easily prepared a library of more than
20 derivatives and examined the biological activity of the compounds
Kinetic Study of the 7-<i>endo</i> Selective Radical Cyclization of <i>N</i>-<i>tert</i>-Butyl‑<i>o</i>‑bromobenzylmethacryl Amides: Kinetic Investigation of the Cyclization and 1,7-Hydrogen Transfer of Aromatic Radicals
A kinetic investigation of the radical
cyclization of <i>N</i>-<i>tert</i>-butyl-<i>o</i>-bromobenzylÂmethacryl
amides to give 2-benzazepines via 7-<i>endo</i> selective
cyclization was undertaken. The aryl radical generated from the amide
precursor by treatment with Bu<sub>3</sub>SnH gave the three compounds,
which are a 7-<i>endo</i> cyclized adduct, a 6-exocyclized
adduct, and a reduced product. The cyclization reactions under various
Bu<sub>3</sub>SnH concentrations were traced by GC analysis. The 7-<i>endo</i>/6-<i>exo</i> selectivity was constant irrespective
of variation in Bu<sub>3</sub>SnH concentration. These results revealed
that regioselectivity is controlled in a kinetic manner and that there
is no possibility of a neophyl rearrangement. The use of Bu<sub>3</sub>SnD revealed that 1,7-hydrogen transfer, in which an aryl radical
abstracts a hydrogen atom from the methallylic methyl group, occurs
during the reaction. Hydrogen abstraction from toluene, the reaction
solvent, was also observed. The 1,7-transfer rate depended on the
Bu<sub>3</sub>SnX (X = H or D), and the reaction kinetics was examined.
The <i>k</i><sub>H</sub>/<i>k</i><sub>D</sub> value
for the hydrogen abstraction of aryl radical from Bu<sub>3</sub>SnX
(X = H or D) was estimated using 4-bromoanisol. The utilization of
these values revealed the overall reaction kinetics and relative rates
for the cyclization and reduction by Bu<sub>3</sub>SnX (X = H or D).
Kinetic parameters for hydrogen abstraction from toluene by aryl radicals
were also estimated