Angewandte Chemie,
Journal Year:
2021,
Volume and Issue:
133(51), P. 26914 - 26921
Published: Oct. 5, 2021
Abstract
The
intermolecular
asymmetric
radical
oxidative
C(sp
3
)−C(sp)
cross‐coupling
of
)−H
bonds
with
readily
available
terminal
alkynes
is
a
promising
method
to
forge
chiral
because
the
high
atom
and
step
economy,
but
remains
underexplored.
Here,
we
report
copper‐catalyzed
(hetero)benzylic
(cyclic)allylic
C−H
that
occurs
excellent
enantioselectivity.
Critical
success
rational
design
oxazoline‐derived
N,N,P(O)‐ligands
not
only
tolerate
strong
conditions
which
are
requisite
for
hydrogen
abstraction
(HAA)
processes
also
induce
challenging
enantiocontrol.
Direct
access
range
synthetically
useful
benzylic
1,4‐enynes,
site‐selectivity
among
similar
bonds,
facile
synthesis
enantioenriched
medicinally
relevant
compounds
make
this
approach
very
attractive.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(47), P. 21674 - 21682
Published: Nov. 17, 2022
Asymmetric
sp3
C–H
functionalization
has
been
demonstrated
to
substantially
expedite
target
molecule
synthesis,
spanning
from
feedstocks
upgradation
late-stage
modification
of
complex
molecules.
Herein,
we
report
a
highly
efficient
and
sustainable
method
for
enantioselective
benzylic
cyanation
by
merging
electrophoto-
copper
catalysis.
A
novel
catalytic
system
allows
one
independently
regulate
the
hydrogen
atom
transfer
step
radical
formation
speciation
Cu(II)/Cu(I)
effectively
capture
transient
intermediate,
through
tuning
electronic
property
anthraquinone-type
photocatalyst
simply
modulating
applied
current,
respectively.
Such
decoupled
relay
catalysis
enables
unified
approach
diverse
alkylarenes,
many
which
are
much
less
reactive
or
even
unreactive
using
existing
relying
on
coupled
relay.
Moreover,
current
protocol
is
also
amenable
bioactive
molecules,
including
natural
products
drugs.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
60(51), P. 26710 - 26717
Published: Oct. 5, 2021
The
intermolecular
asymmetric
radical
oxidative
C(sp3
)-C(sp)
cross-coupling
of
)-H
bonds
with
readily
available
terminal
alkynes
is
a
promising
method
to
forge
chiral
because
the
high
atom
and
step
economy,
but
remains
underexplored.
Here,
we
report
copper-catalyzed
(hetero)benzylic
(cyclic)allylic
C-H
that
occurs
excellent
enantioselectivity.
Critical
success
rational
design
oxazoline-derived
N,N,P(O)-ligands
not
only
tolerate
strong
conditions
which
are
requisite
for
hydrogen
abstraction
(HAA)
processes
also
induce
challenging
enantiocontrol.
Direct
access
range
synthetically
useful
benzylic
1,4-enynes,
site-selectivity
among
similar
bonds,
facile
synthesis
enantioenriched
medicinally
relevant
compounds
make
this
approach
very
attractive.
ACS Catalysis,
Journal Year:
2023,
Volume and Issue:
13(4), P. 2761 - 2770
Published: Feb. 8, 2023
Despite
the
success
of
Sonogashira
coupling
for
synthesis
arylalkynes
and
conjugated
enynes,
engagement
unactivated
alkyl
halides
in
such
reactions
remains
historically
challenging.
We
report
herein
a
strategy
that
merges
Cu-catalyzed
alkyne
transfer
with
aryl
radical
activation
carbon-halide
bonds
to
enable
general
approach
iodides
terminal
alkynes.
This
unprecedented
Sonogashira-type
cross-coupling
reaction
tolerates
broad
range
functional
groups
has
been
applied
late-stage
densely
functionalized
pharmaceutical
agents
as
well
positron
emission
tomography
tracers.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(33), P. 23555 - 23565
Published: Aug. 8, 2024
Copper-catalyzed
coupling
reactions
of
alkyl
halides
are
believed
to
prominently
involve
copper(II)
species
and
radicals
as
pivotal
intermediates,
with
their
exact
interaction
mechanism
being
the
subject
considerable
debate.
In
this
study,
a
visible
light-responsive
fluoroalkylcopper(III)
complex,
[(terpy)Cu(CF3)2(CH2CO2tBu)]
Trans-1,
was
designed
explore
mechanism.
Upon
exposure
blue
LED
irradiation,
Trans-1
undergoes
copper–carbon
bond
homolysis,
generating
Cu(II)
carbon-centered
radicals,
where
radical
then
recombines
intermediate,
resulting
in
formation
Cis-1,
Cis
isomer
Trans-1.
Beyond
this,
well-defined
fluoroalkylcopper(II)
intermediate
ligated
sterically
hindered
ligand
isolated
underwent
full
characterization
electronic
structure
studies.
The
collective
experimental,
computational,
spectroscopic
findings
work
strongly
suggest
that
organocopper(II)
engages
via
an
"oxidative
substitution"
mechanism,
which
is
likely
operational
pathway
for
copper-catalyzed
C–H
trifluoromethylation
reactions.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(21), P. 7903 - 7908
Published: May 18, 2021
We
have
developed
a
method
for
the
stereoselective
coupling
of
terminal
alkynes
and
α-bromo
carbonyls
to
generate
functionalized
E-alkenes.
The
is
accomplished
by
merging
closed-shell
hydrocupration
with
open-shell
single
electron
transfer
(SET)
chemistry
resulting
alkenyl
copper
intermediate.
demonstrate
that
reaction
compatible
various
functional
groups
can
be
performed
in
presence
aryl
bromides,
alkyl
chlorides,
esters,
nitriles,
amides,
wide
range
nitrogen-containing
heterocyclic
compounds.
Mechanistic
studies
provide
evidence
SET
oxidation
intermediate
an
ester
as
key
step
enables
cross
coupling.
Dalton Transactions,
Journal Year:
2022,
Volume and Issue:
52(2), P. 421 - 433
Published: Nov. 29, 2022
A
Cu(II)
complex,
[Cu(HL)(NO3)(CH3OH)]·CH3OH
(1),
was
obtained
by
the
reaction
of
Cu(NO3)2·3H2O
and
H2L
in
methanol
solvent
(H2L
is
(E)-4-amino-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide).
compound
1
were
characterized
various
spectroscopic
analyses
molecular
structure
determined
single-crystal
X-ray
analysis.
The
results
indicated
product
a
mononuclear
complex
contains
free
NH2
functional
group
on
ligand.
used
for
preparation
heterogeneous
catalyst
supporting
it
functionalized
silica
gel.
(Si-Cu)
prepared
an
amidification
with
resulting
silica-supported
TGA,
FT-IR,
EPR,
DRS,
EDS,
XRD,
SEM
XPS
analyses.
Si-Cu
employed
carbon-carbon
coupling
effects
amount
temperature
investigated
catalytic
coupling.
one
products
reactions
(C16H22O2,
CP1)
analysis,
which
proved
formation
C-C
bond
production
di-acetylene
homocoupling
terminal
alkyne.
This
system
stable
can
be
reused
without
significant
change
its
activity.
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(19), P. 11854 - 11859
Published: Sept. 15, 2022
The
methyl
moiety
is
a
key
functional
group
that
can
result
in
major
improvements
the
potency
and
selectivity
of
pharmaceutical
agents.
We
present
radical
relay
C–H
methylation
methodology
employs
β-diketiminate
copper
catalyst
capable
methylating
unactivated
C(sp3)–H
bonds.
Taking
advantage
bench-stable
DABAL-Me3,
an
amine-stabilized
trimethylaluminum
reagent,
range
substrates
possessing
both
activated
bonds
proceeds
with
minimal
amount
overmethylation.
Mechanistic
studies
supported
by
experiment
computation
suggest
intermediacy
copper(II)
intermediate
reactive
toward
loss
as
well
capture
radicals
R•
to
form
R–Me
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(19), P. 13558 - 13570
Published: May 7, 2024
The
Cu-catalyzed
azide–alkyne
cycloaddition
(CuAAC)
reaction
is
used
as
a
ligation
tool
throughout
chemical
and
biological
sciences.
Despite
the
pervasiveness
of
CuAAC,
there
need
to
develop
more
efficient
methods
form
1,4-triazole
ligated
products
with
low
loadings
Cu.
In
this
paper,
we
disclose
mechanistic
model
for
ynamine-azide
(3
+
2)
cycloadditions
catalyzed
by
copper(II)
acetate.
Using
multinuclear
nuclear
magnetic
resonance
spectroscopy,
electron
paramagnetic
high-performance
liquid
chromatography
analyses,
dual
catalytic
cycle
identified.
First,
formation
diyne
species
via
Glaser–Hay
coupling
terminal
ynamine
forms
Cu(I)
competent
catalyze
an
cycloaddition.
Second,
benzimidazole
unit
structure
has
multiple
roles:
assisting
C–H
activation,
Cu
coordination,
postreaction
resting
state
complex
after
completion
Finally,
reactivation
shown
addition
isotopically
labeled
azide
substrates
product.
This
work
provides
basis
use
mixed
valency
binuclear
in
conjunction
Cu-coordinating
alkynes
afford
superior
reactivity
CuAAC
reactions.
Additionally,
these
data
show
how
kinetics
can
be
modulated
changes
alkyne
substrate,
which
then
predictable
effect
on
mechanism.