8 research outputs found
Iron-Catalyzed Intermolecular Oxyamination of Terminal Alkenes Promoted by HFIP Using Hydroxylamine Derivatives
An atom-economical intermolecular iron-catalyzed oxyamination
of
alkenes is described herein. The insertion of oxygenated and nitrogenated
moieties from the hydroxylamine substrate was observed with full regio-
and chemo-selectivity for terminal alkenes in good yields. HFIP as
a solvent appeared to have a synergistic effect with the iron catalyst
to promote the formation of the oxyaminated products. Preliminary
mechanistic studies suggest a pathway going through an aziridination
reaction followed by an in situ ring opening
Development of a One-Pot Four C–C Bond-Forming Sequence Based on Palladium/Ruthenium Tandem Catalysis
A one-pot four C–C
bond-forming sequence has been developed
using two distinct transition metal complexes. The sequence entails
a double Pd-catalyzed allylic alkylation followed by a Ru-catalyzed
ring-closing metathesis and a Pd-catalyzed Heck coupling. The use
of various active methylene nucleophiles was examined with yields
up to 76% (93% per C–C bond)
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
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
Iron-Catalyzed Intramolecular C(sp<sup>3</sup>)‑H Lactonization of Hydroxamate Derivatives Promoted by a 1,5-HAT
An iron-catalyzed lactonization reaction via intramolecular
C(sp3)-H functionalization is described. The process employs
easily
accessible hydroxamate derivatives from which the noncommon insertion
of the oxygen occurred through a 1,5-hydrogen atom transfer. A mixture
of water and hexafluoroisopropanol as solvent appeared to be the key
parameter of this transformation to reach a high selectivity and efficiency
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)