Organic Letters,
Journal Year:
2020,
Volume and Issue:
22(15), P. 5984 - 5989
Published: July 24, 2020
An
efficient,
photoredox-catalyst-free
radical
alkylation
of
quinoxalin-2(1H)-ones
has
been
described.
This
reaction
utilizes
4-alkyl-1,4-dihydropyridines
(R-DHPs)
as
alkyl
precursors
and
acetoxybenziodoxole
(BI-OAc)
an
electron
acceptor
to
undergo
single-electron
transfer
with
photoexcited
R-DHPs.
The
benign
conditions
allow
for
good
compatibility
in
the
scope
both
synthetic
value
protocol
was
also
demonstrated
by
successful
functionalization
natural
products
drug-based
complex
molecules
Chemical Society Reviews,
Journal Year:
2021,
Volume and Issue:
50(13), P. 7587 - 7680
Published: Jan. 1, 2021
Organic
compounds
that
show
Thermally
Activated
Delayed
Fluorescence
(TADF)
have
become
wildly
popular
as
next
generation
emitters
in
organic
light-emitting
diodes
(OLEDs),
but
since
2016,
received
significant
and
increasing
attention
photocatalysts.
Chemical Society Reviews,
Journal Year:
2020,
Volume and Issue:
50(2), P. 766 - 897
Published: Dec. 22, 2020
Recent
developments
and
future
prospects
of
visible-light
photocatalysis
in
the
late-stage
functionalization
pharmaceuticals
natural
bioactive
compounds.
ACS Catalysis,
Journal Year:
2020,
Volume and Issue:
10(12), P. 6862 - 6869
Published: June 8, 2020
N-Heterocyclic
carbene
(NHC)
organocatalysis
to
promote
so-called
umpolung
reactions
has
emerged
as
a
powerful
tool
for
modern
organic
synthesis.
NHC-bound
nucleophiles
known
Breslow
intermediates
can
be
obtained
by
reacting
an
NHC
catalyst
with
aldehyde
and
will
add
carbon–heteroatom
or
carbon–carbon
double
bonds.
On
the
other
hand,
substitution-type
cross-couplings
of
carbon
electrophiles
(that
is,
R–X
species)
generate
bonds
have
also
been
demonstrated
even
though
such
processes
are
difficult
less
mature
at
present.
This
Perspective
briefly
summarizes
NHC-based
catalysis
enabling
cross-coupling
reactions.
Three
types
systems
examined:
anionic,
hybrid,
radical
catalysis.
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(19), P. 11984 - 11999
Published: Sept. 19, 2022
Radical/radical
cross-coupling
reactions
represent
an
efficient
and
straightforward
approach
for
the
construction
of
chemical
bonds
accordingly
have
drawn
increasing
attention
over
past
decades.
In
order
to
achieve
synthetically
useful
transformations,
a
persistent
radical
should
be
coupled
with
transient
in
accordance
effect
(PRE).
However,
known
radicals
outnumber
by
far
types
free
radicals,
which
limits
widespread
application
PRE,
until
today.
Thus,
development
between
has
been
focus,
meanwhile
transition-metal
catalysis
successfully
implemented
artificially
prolong
lifetimes,
allowing
their
utilization
formal
radical/radical
cross-couplings.
Complementary
research
field
recently
uncovered
that
organocatalytically
generated
NHC-derived
ketyl
are
type
catalytically
radicals.
NHC-catalyzed
transformations
aldehydes
carboxylic
acid
derivatives
enabled
disclosure
ever-increasing
number
interesting
reactions,
different
from
traditional
ionic
processes,
offering
otherwise
inaccessible
activation
modes.
These
discoveries
opened
door
NHC
organocatalysis
manipulation
reactions.
Due
its
obvious
potential
synthetic
organic
chemistry,
it
is
timely
provide
perspective
on
this
emerging
field.
Angewandte Chemie International Edition,
Journal Year:
2020,
Volume and Issue:
59(45), P. 19956 - 19960
Published: July 23, 2020
Despite
the
great
potential
of
radical
chemistry
in
organic
synthesis,
N-heterocyclic
carbene
(NHC)-catalyzed
reactions
involving
intermediates
are
not
well
explored.
This
communication
reports
three-component
coupling
aroyl
fluorides,
styrenes
and
Langlois
reagent
(CF3
SO2
Na)
to
give
various
β-trifluoromethylated
alkyl
aryl
ketones
with
good
functional
group
tolerance
moderate
high
yields
by
cooperative
photoredox/NHC
catalysis.
The
alkene
acyltrifluoromethylation
proceeds
via
radical/radical
cross
ketyl
radicals
benzylic
C-radicals.
generated
SET
reduction
situ
formed
acylazolium
ions
whereas
derive
from
trifluoromethyl
addition
onto
styrenes.
Chemical Science,
Journal Year:
2020,
Volume and Issue:
11(39), P. 10605 - 10613
Published: Jan. 1, 2020
N-Heterocyclic
carbenes
(NHCs)
are
efficient
Lewis
basic
catalysts
for
the
umpolung
of
various
polarized
unsaturated
compounds
usually
including
aldehydes,
imines,
acyl
chlorides
and
activated
esters.
NHC
catalysis
involving
electron
pair
transfer
steps
has
been
extensively
studied;
however,
through
single-electron
(SET)
processes,
despite
having
potential
to
achieve
chemical
transformations
inert
bonds
using
green
reagents,
long
a
challenging
task
in
organic
synthesis.
In
parallel,
visible-light-induced
photocatalysis
photoexcitation
have
established
as
powerful
tools
facilitate
sustainable
synthesis,
they
enable
generation
reactive
radical
intermediates
under
extremely
mild
conditions.
Recently,
number
elegant
visible-light-induced,
NHC-catalyzed
were
developed
accessing
valuable
compounds.
As
result,
this
minireview
will
highlight
recent
advances
field.
