RSC Sustainability,
Journal Year:
2024,
Volume and Issue:
2(8), P. 2169 - 2189
Published: Jan. 1, 2024
This
review
describes
the
recent
advancements
in
visible
light-induced
bromine
radical
enhanced
hydrogen
atom
transfer
(HAT)
reactions
organic
synthesis.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(13), P. 7600 - 7611
Published: March 23, 2023
Catalytic
C(sp3)-H
functionalization
has
provided
enormous
opportunities
to
construct
organic
molecules,
facilitating
the
derivatization
of
complex
pharmaceutical
compounds.
Within
this
framework,
direct
hydrogen
atom
transfer
(HAT)
photocatalysis
becomes
an
appealing
approach
goal.
However,
viable
substrates
utilized
in
these
protocols
are
limited,
and
site
selectivity
shows
preference
activated
thermodynamically
favored
bonds.
Herein,
we
describe
development
undirected
iron-catalyzed
borylation,
thiolation,
sulfinylation
reactions
enabled
by
photoinduced
ligand-to-metal
charge
(LMCT)
process.
These
exhibit
remarkably
broad
substrate
scope
(>150
examples
total),
most
importantly,
all
three
show
unconventional
regioselectivity,
with
occurrence
preferentially
at
distal
methyl
position.
The
procedures
operationally
simple
readily
scalable
provide
access
high-value
products
from
hydrocarbons
one
step.
Mechanistic
studies
control
experiments
indicate
that
afforded
is
not
only
relevant
HAT
species
but
also
largely
affected
use
boron-
sulfone-based
radical
acceptors.
ACS Catalysis,
Journal Year:
2023,
Volume and Issue:
13(2), P. 1125 - 1132
Published: Jan. 9, 2023
Ligand-to-metal
charge
transfer
(LMCT)
photocatalysis
allows
the
activation
and
synthetic
utilization
of
halides
other
heteroatoms
in
metal
complexes.
Many
metals
are
known
to
undergo
LMCT
but
so
far
remain
underutilized
field
catalysis.
A
screening
assay
identifying
activity
helped
us
expand
this
catalysis
concept
application
bismuth
organic
radical
coupling
reactions.
We
demonstrate
its
for
generation
two
different
radicals
(chlorine
carboxyl)
net-oxidative
as
well
redox-neutral
photochemical
Detailed
investigation
model
Giese-type
revealed
BiCl4–
BiCl52–
catalytically
active
species
under
385
nm
irradiation.
Combined
cyclic
voltammetry
UV–vis
studies
gave
insight
into
reactivity
highly
reactive
bismuth(II)
catalyst
fragment.
Chemical Society Reviews,
Journal Year:
2024,
Volume and Issue:
53(14), P. 7309 - 7327
Published: Jan. 1, 2024
Oxidative
degradation
is
a
powerful
method
to
degrade
plastics
into
oligomers
and
small
oxidized
products.
While
thermal
energy
has
been
conventionally
employed
as
an
external
stimulus,
recent
advances
in
photochemistry
have
enabled
photocatalytic
oxidative
of
polymers
under
mild
conditions.
This
tutorial
review
presents
overview
degradation,
from
its
earliest
examples
emerging
strategies.
briefly
discusses
the
motivation
development
with
focus
on
underlying
mechanisms.
Then,
we
will
examine
modern
studies
primarily
relevant
catalytic
degradation.
Lastly,
highlight
some
unique
using
unconventional
approaches
for
polymer
such
electrochemistry.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(22), P. 15331 - 15344
Published: May 23, 2024
Within
the
context
of
Ni
photoredox
catalysis,
halogen
atom
photoelimination
from
has
emerged
as
a
fruitful
strategy
for
enabling
hydrogen
transfer
(HAT)-mediated
C(sp3)–H
functionalization.
Despite
numerous
synthetic
transformations
invoking
this
paradigm,
unified
mechanistic
hypothesis
that
is
consistent
with
experimental
findings
on
catalytic
systems
and
accounts
radical
formation
facile
C(sp2)–C(sp3)
bond
remains
elusive.
We
employ
kinetic
analysis,
organometallic
synthesis,
computational
investigations
to
decipher
mechanism
prototypical
Ni-catalyzed
photochemical
arylation
reaction.
Our
revise
previous
proposals,
first
by
examining
relevance
SET
EnT
processes
intermediates
relevant
HAT-based
investigation
highlights
ability
blue
light
promote
efficient
Ni–C(sp2)
homolysis
cationic
NiIII
reductive
elimination
bipyridine
NiII
complexes.
However
interesting,
rates
selectivities
these
do
not
account
productive
pathway.
Instead,
our
studies
support
involves
evolution
in
situ
generated
dihalide
intermediates,
capture
NiII(aryl)(halide)
resting
state,
key
C–C
NiIII.
Oxidative
addition
NiI,
opposed
Ni0,
rapid
NiIII/NiI
comproportionation
play
roles
process.
The
presented
herein
offer
fundamental
insight
into
reactivity
broader
catalysis.
ACS Catalysis,
Journal Year:
2025,
Volume and Issue:
unknown, P. 4665 - 4680
Published: March 5, 2025
Transition
metal
catalysis
is
an
indispensable
tool
for
organic
synthesis
that
has
been
harnessed,
modulated,
and
perfected
many
decades
by
careful
selection
of
centers
ligands,
giving
rise
to
synthetic
methods
with
unparalleled
efficiency
chemoselectivity.
Recent
developments
have
demonstrated
how
light
irradiation
can
also
be
recruited
as
a
powerful
dramatically
alter
the
outcome
catalytic
reactions,
providing
access
innovative
pathways
remarkable
potential.
In
this
context,
adoption
photochemical
conditions
mainstream
strategy
drive
reactions
unveiled
exciting
opportunities
exploit
rich
excited-state
framework
transition
metals
applications.
This
Perspective
examines
advances
in
application
complexes
standalone
photocatalysts,
exploiting
innate
reactivity
their
excited
states
beyond
common
use
photoredox
catalysts.
An
account
relevant
examples
dissected
provide
discussion
on
electronic
reorganization,
orbitals
involved,
associated
different
types
states.
analysis
aims
practitioners
fundamental
principles
guiding
strategies
understand,
design,
apply
light-activation
homogeneous
synthesis.
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(18), P. 11216 - 11225
Published: Sept. 1, 2022
A
strategy
for
both
cross-electrophile
coupling
and
1,2-dicarbofunctionalization
of
olefins
has
been
developed.
Carbon-centered
radicals
are
generated
from
alkyl
bromides
by
merging
benzophenone
hydrogen
atom
transfer
(HAT)
photocatalysis
silyl
radical-induced
halogen
(XAT)
subsequently
intercepted
a
nickel
catalyst
to
forge
the
targeted
C(sp3)-C(sp2)
C(sp3)-C(sp3)
bonds.
The
mild
protocol
is
fast
scalable
using
flow
technology,
displays
broad
functional
group
tolerance,
amenable
wide
variety
medicinally
relevant
moieties.
Mechanistic
investigations
reveal
that
ketone
catalyst,
upon
photoexcitation,
responsible
direct
activation
silicon-based
XAT
reagent
(HAT-mediated
XAT)
furnishes
radical
ultimately
involved
in
turnover
catalytic
cycle.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
145(2), P. 991 - 999
Published: Dec. 30, 2022
Herein,
we
present
a
comprehensive
study
on
the
use
of
N-heterocyclic
carbene
(NHC)-ligated
boryl
radicals
to
enable
C(sp3)–C(sp3)
bond
formation
under
visible-light
irradiation
via
Halogen-Atom
Transfer
(XAT).
The
methodology
relies
an
acridinium
dye
generate
boron-centered
from
corresponding
NHC-ligated
boranes
single-electron
transfer
(SET)
and
deprotonation.
These
subsequently
engage
with
alkyl
halides
in
XAT
step,
delivering
desired
nucleophilic
radicals.
strategy
is
very
mild
accommodates
broad
scope
halides,
including
medicinally
relevant
compounds
biologically
active
molecules.
key
role
operative
reaction
mechanism
has
been
elucidated
through
combination
experimental,
spectroscopic,
computational
studies.
This
stands
as
significant
advancement
chemistry
radicals,
which
had
long
restricted
radical
reductions,
enabling
C–C
photoredox
conditions.
Nature Communications,
Journal Year:
2022,
Volume and Issue:
13(1)
Published: Oct. 18, 2022
Photocatalytic
hydrogen
atom
transfer
(HAT)
processes
have
been
the
object
of
numerous
studies
showcasing
potential
homogeneous
photocatalyst
tetrabutylammonium
decatungstate
(TBADT)
for
functionalization
C(sp3)-H
bonds.
However,
to
translate
these
into
large-scale
industrial
processes,
careful
considerations
catalyst
loading,
cost,
and
removal
are
required.
This
work
presents
organic
solvent
nanofiltration
(OSN)
as
an
answer
reduce
TBADT
consumption,
increase
its
turnover
number
lower
concentration
in
product
solution,
thus
enabling
photocatalytic
HAT-based
transformations.
The
operating
parameters
a
suitable
membrane
recovery
acetonitrile
were
optimized.
Continuous
alkylation
amination
reactions
carried
out
with
in-line
via
two
OSN
steps.
Promisingly,
observed
yields
recycling
comparable
those
performed
pristine
TBADT,
therefore
highlighting
that
not
only
(>99%,
TON
>
8400)
is
possibility,
but
also
it
does
happen
at
expense
reaction
performance.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(36)
Published: July 17, 2023
Abstract
Despite
their
abundance
in
organic
molecules,
considerable
limitations
still
exist
synthetic
methods
that
target
the
direct
C−H
functionalization
at
sp
3
‐hybridized
carbon
atoms.
This
is
even
more
case
for
light
alkanes,
which
bear
some
of
strongest
bonds
known
Nature,
requiring
extreme
activation
conditions
are
not
tolerant
to
most
molecules.
To
bypass
these
issues,
chemists
rely
on
prefunctionalized
alkyl
halides
or
organometallic
coupling
partners.
However,
new
regioselectively
a
variety
different
scaffolds
would
be
great
added
value,
only
late‐stage
biologically
active
molecules
but
also
catalytic
upgrading
cheap
and
abundant
hydrocarbon
feedstocks.
Here,
we
describe
general,
mild
scalable
protocol
enables
C(sp
)−H
carbonylation
saturated
hydrocarbons,
including
natural
products
using
photocatalytic
hydrogen
atom
transfer
(HAT)
gaseous
monoxide
(CO).
Flow
technology
was
deemed
crucial
enable
high
gas‐liquid
mass
rates
fast
reaction
kinetics,
needed
outpace
deleterious
pathways,
leverage
safe
process.