Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 23, 2024
Nickel-catalyzed
cross-electrophile
coupling
(XEC)
reactions
of
(hetero)aryl
electrophiles
represent
appealing
alternatives
to
palladium-catalyzed
methods
for
biaryl
synthesis,
but
they
often
generate
significant
quantities
homocoupling
and/or
proto-dehalogenation
side
products.
In
this
study,
an
informer
library
heteroaryl
chloride
and
aryl
bromide
partners
is
used
identify
Ni-catalyzed
XEC
conditions
that
access
high
selectivity
the
cross-product
when
using
equimolar
two
substrates.
Two
different
catalyst
systems
are
identified
show
complementary
scope
broad
functional-group
tolerance,
time-course
data
suggest
follow
mechanisms.
A
NiBr
Science,
Journal Year:
2024,
Volume and Issue:
385(6715), P. 1331 - 1337
Published: Sept. 19, 2024
The
myriad
nickel-catalyzed
cross-coupling
reactions
rely
on
the
formation
of
an
organonickel
intermediate,
but
limitations
in
forming
monoalkylnickel
species
have
limited
options
for
C(sp
3
)
cross-coupling.
monoalkylnickel(II)
from
abundant
carboxylic
acid
esters
would
be
valuable,
derivatives
are
primarily
decarboxylated
to
form
alkyl
radicals
that
lack
correct
reactivity.
In
this
work,
we
disclose
a
facile
oxidative
addition
and
decarbonylation
sequence
forms
intermediates
through
nonradical
process.
key
ligand,
bis(4-methylpyrazole)pyridine,
accelerates
decarbonylation,
stabilizes
alkylnickel(II)
destabilizes
off-cycle
nickel(0)
carbonyl
species.
utility
new
reactivity
)-C(sp
bond
is
demonstrated
reaction
challenging
by
purely
radical
methods—the
selective
primary
with
iodides.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(47), P. 32249 - 32254
Published: Nov. 15, 2024
Sacrificial
anodes
composed
of
inexpensive
metals
such
as
Zn,
Fe,
and
Mg
are
widely
used
to
support
electrochemical
nickel-catalyzed
cross-electrophile
coupling
(XEC)
reactions,
in
addition
other
reductive
transformations.
Such
appealing
because
they
provide
a
stable
counter-electrode
potential
typically
avoid
interference
with
the
chemistry.
The
present
study
outlines
development
an
Ni-catalyzed
XEC
reaction
that
streamlines
access
key
pharmaceutical
intermediate.
Metal
ions
derived
from
sacrificial
anode
oxidation,
however,
directly
contribute
homocoupling
proto-dehalogenation
side
products
commonly
formed
chemical
reactions.
Use
divided
cell
limits
by
anode-derived
metal
supports
high
product
yield
negligible
formation,
introducing
strategy
overcome
one
main
limitations
XEC.
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 10, 2025
Aryl
triflates
make
up
a
class
of
aryl
electrophiles
that
are
available
in
single
step
from
the
corresponding
phenol.
Despite
known
reactivity
nickel
complexes
for
C-O
bond
activation
phenol
derivatives,
nickel-catalyzed
cross-electrophile
coupling
using
has
proven
challenging.
Herein,
we
report
method
to
form
C(sp2)-C(sp3)
bonds
by
with
alkyl
bromides
and
chlorides
phenanthroline
(phen)
or
pyridine-2,6-bis(N-cyanocarboxamidine)
(PyBCamCN)-ligated
catalysts.
The
scope
reaction
is
demonstrated
38
examples
(61
±
14%
average
yield).
Mechanistic
studies
provide
rationale
conditions
used
roadmap
further
applications
coupling.
First,
rate
radical
generation
controlled
maintaining
majority
halide
as
chloride,
which
unreactive,
utilizing
dynamic
exchange
process
adjust
concentration
reactive
bromide
iodide.
Second,
challenge
electron-rich
appears
be
due
off-cycle
transmetalation
unproductive
zinc
reagents.
optimal
PyBCamCN
ligand
together
LiCl
avoids
this
deleterious
step.
Inorganics,
Journal Year:
2025,
Volume and Issue:
13(2), P. 41 - 41
Published: Feb. 1, 2025
Six
N^C^N
cyclometalated
Ni(II)
complexes
[Ni(N^C^N)Cl]
or
[Ni(N^C^N’)Br]
with
symmetric
non-symmetric
N^C^N’
ligands
in
which
the
peripheral
N-groups
were
varied
pyridine
(Py),
4-thiazole
(4Tz),
2-thiazole
(2Tz),
and
2-benzothiazole
(2Btz)
complementing
previously
reported
di(2-pyridyl)phenide
[Ni(Py(Ph)Py)X]
X
=
Cl
Br.
The
synthesized
from
NiBr2
N^CH^N’
protoligands
through
base-assisted
nickelation,
while
received
N^C(Cl)^N
[Ni(COD)2]
(COD
1,5-cyclooctadiene).
Introduction
of
4Tz
on
both
sides
shifted
electrochemical
gap
ΔEexp
Eox–Ered
long
wavelength
UV-vis
absorption
maxima
to
higher
energies,
2Tz
leads
a
shift
lower
energies.
When
introducing
only
one
as
groups,
remaining
PhPy
moiety
dominates
electronic
properties
electrochemistry
photophysics
are
very
similar
Py(Ph)Py
derivatives.
In
contrast
this,
introduction
2Btz
shifts
values
regardless
two
groups
character
frontier
molecular
orbitals
complexes,
DFT
calculations
show.
Long-wavelength
absorptions
vary
416
443
nm,
their
energies
correlate
well
first
reduction
potentials.
Negishi-type
C–C
cross-coupling
reactions
gave
total
yields
ranging
1
60%
44%.
reactivities
roughly
Facilitated
(E
around
–2
higher)
goes
generally
along
improved
performance,
making
thiazole-containing
interesting
candidates
for
such
catalysis.
We
report
herein
our
studies
on
the
direct
photoactivation
of
carbonyl
cyclopropanes
to
give
biradical
intermediates,
leading
selective
cleavage
more
substituted
carbon-carbon
bond.
Depending
substrate
structure,
extended
alkenes
were
isolated
or
directly
reacted
in
a
photo-Nazarov
process
bicyclic
products.
Based
these
results,
unified
reductive
ring-opening
reaction
was
developed
by
using
diphenyl
disulfide
as
HAT
reagent.
By
performing
sequential
cyclopropanation/selective
ring
opening
reaction,
we
achieved
CH2
insertion
into
,-
bond
both
acyclic
and
cyclic
un-saturated
compounds.
Our
protocol
therefore
provides
further
tool
for
framework-editing
carbocycles,
com-plementing
recent
progress
"skeletal
editing"
strategies.
We
report
herein
our
studies
on
the
direct
photoactivation
of
carbonyl
cyclopropanes
to
give
biradical
intermediates,
leading
selective
cleavage
more
substituted
carbon-carbon
bond.
Depending
substrate
structure,
extended
alkenes
were
isolated
or
directly
reacted
in
a
photo-Nazarov
process
bicyclic
products.
Based
these
results,
unified
reductive
ring-opening
reaction
was
developed
by
using
diphenyl
disulfide
as
HAT
reagent.
By
performing
sequential
cyclopropanation/selective
ring
opening
reaction,
we
achieved
CH2
insertion
into
alpha,beta-
bond
both
acyclic
and
cyclic
unsaturated
compounds.
Our
protocol
therefore
provides
further
tool
for
framework-editing
carbocycles,
complementing
recent
progress
"skeletal
editing"
strategies.
Organic Chemistry Frontiers,
Journal Year:
2024,
Volume and Issue:
11(23), P. 6712 - 6717
Published: Jan. 1, 2024
A
visible
light-promoted
synthesis
route
to
fused
tetracyclic
skeletons
with
rich
sp
3
carbons
through
stepwise
radical
cycloadditions
and
further
cyclization
of
the
final
intermediates
adjacent
aromatic
rings
was
developed.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 31, 2024
We
report
herein
our
studies
on
the
direct
photoactivation
of
carbonyl
cyclopropanes
to
give
biradical
intermediates,
leading
selective
cleavage
more
substituted
carbon-carbon
bond.
Depending
substrate
structure,
extended
alkenes
were
isolated
or
directly
reacted
in
a
photo-Nazarov
process
bicyclic
products.
Based
these
results,
unified
reductive
ring-opening
reaction
was
developed
by
using
diphenyl
disulfide
as
hydrogen
atom
transfer
(HAT)
reagent.
By
performing
sequential
cyclopropanation/selective
ring
opening
reaction,
we
achieved
CH
