9 research outputs found
Enantioselective Synthesis of 1-Aryl-tetrahydroisoquinolines through Iridium Catalyzed Asymmetric Hydrogenation
Asymmetric hydrogenation of 1-aryl-3,4-dihydroisoquinolines using the [IrCODCl]<sub>2</sub>/(<i>R</i>)-3,5-diMe-Synphos catalyst is reported. Under mild reaction conditions, this atom-economical process provides easy access to a variety of enantioenriched 1-aryl-1,2,3,4-tetrahydroisoquinoline derivatives, which are important pharmacophores found in several pharmaceutical drug candidates, in high yields and enantiomeric excesses up to 99% after a single crystallization
Enantioselective Rhodium-Catalyzed Synthesis of α-Chloromethylene-γ-Butyrolactams from <i>N</i>-Allylic Alkynamides
The first enantioselective cycloisomerization with intramolecular halogen migration of various 1,6-enynes promoted by a cationic Rh-Synphos catalyst is reported. This method provides an efficient route to enantiomerically enriched γ-butyrolactam derivatives, which are important core scaffolds found in numerous natural products and biologically active molecules. Good yields and enantiomeric excesses up to 96% are achieved
Synthesis and Antiproliferative and Metabolic Evaluations of Novel Securinine Derivatives
New securinine analogues have been
prepared by semisynthesis. Two
series were developed using either Suzuki or Sonogashira cross coupling
reactions. The <i>in vitro</i> cytotoxicity of the compounds
was assayed against HCT-116 colon cancer cells. The most potent derivatives
showed promising growth inhibition on four tumoral cell lines giving
a valuable insight on the structure–activity relationship (SAR)
of securinine. Moreover, high antiproliferative effect against A-375
(melanoma) was observed with IC<sub>50</sub> up to 60 nM
Palladium-Catalyzed Efficient Enantioselective Synthesis of Chiral Allenes: Steric and Electronic Effects of Ligands
Asymmetric synthesis of chiral allenes
starting from prochiral
substrates under mild reaction conditions promoted by Pd-SYNPHOS catalyst
is reported. This protocol provides an efficient access to various
enantioenriched aryl- and alkyl- substituted allenes, which are versatile
building blocks of high utility to both organic and medicinal chemists,
in excellent isolated yields (up to 96%) and high enatiomeric ratio
values (up to 95:5). In addition, a comparative study using several <i>C</i><sub>2</sub>-symmetric atropisomeric diphosphine ligands
revealed the overwhelming impact of the steric and electronic properties
of the ligands for the catalytic efficiency of this process
Enantioselective Ruthenium(II)/Xyl-SunPhos/Daipen-Catalyzed Hydrogenation of γ‑Ketoamides
A series of γ-hydroxy amides
were synthesized with high enantioselectivities
(up to 99%) using asymmetric hydrogenation of the corresponding γ-ketoamides
in the presence of Ru-Xyl-SunPhos-Daipen catalyst providing key building
blocks for a variety of naturally occurring and biologically active
compounds
Ruthenium-Catalyzed Enantioselective Hydrogenation of Aryl-Pyridyl Ketones
Various substituted aryl-pyridyl ketones were hydrogenated
in the
presence of Ru-XylSunPhos-Daipen bifunctional catalytic system with
enantiomeric excesses up to 99.5%. Upon introduction of a readily
removable <i>ortho</i>-bromo atom to the phenyl ring, enantiomerically
enriched 4-chlorophenylpyridylmethanol was obtained by hydrogenation method
with 97.3% ee, which provided an important chiral intermediate for
some histamine H<sub>1</sub> antagonists
General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Unusual Halide Effect and Synthetic Application
A general asymmetric hydrogenation of a wide range of
2-alkyl-
and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium–difluorphos
complex has been developed. Under mild reaction conditions, the corresponding
biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline
units were obtained in high yields and good to excellent enantioselectivities
up to 95%. With a catalyst ratio of S/C = 1000 and on a gram scale,
the catalytic activity of the Ir–difluorphos complex was maintained
showing its potential value. Finally, we demonstrated the application
of our process in the synthesis of compound (<i>S</i>)-<b>9</b>, which is an inhibitor of cholesteryl ester transfer protein
(CETP)
General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Unusual Halide Effect and Synthetic Application
A general asymmetric hydrogenation of a wide range of
2-alkyl-
and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium–difluorphos
complex has been developed. Under mild reaction conditions, the corresponding
biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline
units were obtained in high yields and good to excellent enantioselectivities
up to 95%. With a catalyst ratio of S/C = 1000 and on a gram scale,
the catalytic activity of the Ir–difluorphos complex was maintained
showing its potential value. Finally, we demonstrated the application
of our process in the synthesis of compound (<i>S</i>)-<b>9</b>, which is an inhibitor of cholesteryl ester transfer protein
(CETP)
General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Unusual Halide Effect and Synthetic Application
A general asymmetric hydrogenation of a wide range of
2-alkyl-
and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium–difluorphos
complex has been developed. Under mild reaction conditions, the corresponding
biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline
units were obtained in high yields and good to excellent enantioselectivities
up to 95%. With a catalyst ratio of S/C = 1000 and on a gram scale,
the catalytic activity of the Ir–difluorphos complex was maintained
showing its potential value. Finally, we demonstrated the application
of our process in the synthesis of compound (<i>S</i>)-<b>9</b>, which is an inhibitor of cholesteryl ester transfer protein
(CETP)