Visible
light
photocatalysis
is
now
recognized
as
a
cornerstone
to
drive
radical-based
transformations
with
good
efficiency
and
versatility
under
environmentally
friendly
reaction
conditions.
However,
the
high
reactivity
of
photogenerated
intermediates
imparts
several
challenges
for
controlling
stereoselectivity
process.
This
chapter
provides
an
overview
on
major
achievements
in
asymmetric
photoredox
catalysis.
Specifically,
two
types
enantioselective
photocatalytic
strategies
are
outlined.
The
first
one
involves
synergistic
merger
achiral
photocatalyst
chiral
co-catalyst.
part
divided
according
mode
catalysis
including
Lewis
base
catalysis,
hydrogen-bond
Brønsted
or
acid
catalyzes,
phase
transfer
second
strategy
deals
employment
single
organophotocatalyst
organometallic
photocatalyst.
The Journal of Organic Chemistry,
Год журнала:
2020,
Номер
85(4), С. 2385 - 2394
Опубликована: Янв. 13, 2020
A
novel
and
convenient
visible
light-catalyzed
tandem
radical
cyclization
of
N-propargylindoles
with
acyl
chlorides
for
accessing
2-acyl-9H-pyrrolo[1,2-a]indoles
is
established.
This
transformation
involves
sequential
addition
the
to
carbon-carbon
triple
bond,
intramolecular
2-position
indole,
isomerization
double
bond.
The
experimental
results
show
that
this
reaction
contains
a
pathway
chain
process
not
major
formation
products.
The Journal of Organic Chemistry,
Год журнала:
2022,
Номер
87(5), С. 3788 - 3793
Опубликована: Фев. 21, 2022
A
novel
tetrahydroxydiboron
and
nickel
chloride
cocatalyzed
radical
cyclization
cascade
with
a
broad
substrate
scope
an
ultrashort
reaction
time
was
developed.
The
mechanistic
investigation
indicated
that
the
might
involve
homocleavage
of
hydride
intermediates.
This
approach
enables
simple
efficient
synthesis
series
heteropolycycles.
Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(19), С. 3182 - 3210
Опубликована: Авг. 1, 2023
Abstract
Heterocyclic
scaffolds
are
beneficial
structural
architects
in
a
wide
range
of
pharmaceuticals,
agrochemicals,
biological
and
also
functional
materials.
In
this
regard,
several
investigations
have
been
performed
to
synthesize
them.
Among
these,
visible
light‐induced
difunctionalization
cyclization
strategy
provides
attractive
solutions
by
adopting
greener
routes,
breaking
the
monopoly
conventional
thermal
processes.
A
review
on
these
methodologies
is
desirable
as
unsaturated
aliphatics,
especially
alkenes
one
cheapest
feedstocks
available.
They
offer
diverse
options
modifications
generate
different
products,
including
heterocycles,
which
highly
sought
after
due
their
applications
various
sectors.
To
account
for
advancements
strategy,
we
summarized
light
induced
strategies
that
directly
lead
synthesis
heterocyclic
from
C−C
bonds.
We
categorized
relevant
reaction
schemes
into
four
mechanistically
distinct
sections
namely
(i)
Two
component
oxidative
annulations
(ii)
Radical
mediated
(iii)
Polar
radical
crossover
(iv)
Three
annulations.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(49)
Опубликована: Окт. 19, 2023
Four-membered
carbocycles
are
important
structural
motifs
found
in
several
natural
products
and
drugs.
Amongst
those,
cyclobutenes
attractive
intermediates
because
the
residual
olefin
can
be
manipulated
selectively
into
various
saturated
unsaturated
analogs.
Few
methods
exist
to
access
chiral
tri-
tetra-C-substituted
they
generally
limited
terms
of
diversification.
Herein,
a
divergent
synthetic
strategy
was
developed
where
single
optically
enriched
scaffold
is
diversified
variety
derivatives
with
different
substitution
patterns.
To
this
end,
enantioselective
desymmetrization
prochiral
1,2-dibromocyclobutene
imides
enabled
by
dual
Ir/Ni-catalyzed
photoredox
C(sp2
)-C(sp3
)
cross-coupling
an
alkyltrifluoroborate
salt
install
convertible
carbon
fragment
good
yields
>90
%
enantiomeric
excess.
Exceptional
mono-coupling
selectivity
observed
resulting
bromocyclobutene
serves
as
common
that
transformed
manner
valuable
1,2,3,4-tetra-C-substituted
cyclobutane
while
maintaining
optical
purity.
Catalysis Reviews,
Год журнала:
2020,
Номер
64(4), С. 679 - 715
Опубликована: Окт. 25, 2020
In
the
past
three
decades,
rare-earth
metal
triflates
including
scandium
triflate,
yttrium
and
lanthanide
(La−Lu)
were
widely
employed
in
organic
chemistry,
such
as
cyclization,
C-H
bond
functionalization
types
of
reactions.
Recently,
approaches
using
catalysts
have
been
mainly
focusing
on
(1)
achieving
high
regioselectivity
stereoselectivity
with
effective
ligands
(2)
further
extending
reaction
scope
by
cooperation
other
transition
catalysts.
This
review
focuses
recent
advances
triflates-catalyzed
reactions
from
2017
to
2019.
also
emphasis
transformations
related
mechanisms
show
general
readership
about
capabilities,
challenges
well
potential
applications.
Abstract
Polycyclic
indoles
are
prevailed
in
natural
products,
pharmaceuticals
and
biologically
active
compounds.
Herein
is
described
photo‐induced
difluoromethylation‐cyclization
of
N
‐alkene
tethered
to
synthesis
tetrahydropyrido[1,2‐
a
]indole
using
5‐((difluoromethyl)sulfonyl)‐1‐phenyl‐1H‐tetrazole
as
CF
2
H
radical
source.
This
photochemical
reaction
tolerates
an
array
functional
groups
like
ester,
cyano,
ketone,
halide,
ether,
aldehyde
heteocycles.
Mechanistic
experiments
indicated
that
the
difluoromethyl
single
electron
transfer
were
involved.
European Journal of Organic Chemistry,
Год журнала:
2021,
Номер
2022(3)
Опубликована: Ноя. 9, 2021
Abstract
The
redox‐neutral
palladium‐catalyzed
dicarbofunctionalization
of
unactivated
alkenes
with
a
variety
functionalized
difluoromethyl
and
perfluoroalkyl
halide
is
presented
here.
This
transformation
proceeds
smoothly
at
low
temperatures
enables
the
assembly
diversified
fluoroalkylated
pyrrolo[1,2‐a]indole
derivatives
one
all‐carbon
quaternary
center
in
high
regioselectivity.
Mechanistic
studies
suggested
an
operative
radical
mechanism
initiation
inner‐sphere
single
electron
transfer
between
dual
phosphine
ligand‐coordinated
palladium(0)
species
halides.
Journal of Heterocyclic Chemistry,
Год журнала:
2024,
Номер
61(8), С. 1248 - 1260
Опубликована: Май 29, 2024
Abstract
Visible‐light‐mediated
formation
of
tetrahydrobenzofuranone
by
direct
oxidative
[3
+
2]
cycloaddition
via
coupling
between
dimedone
and
chalcone
using
eosin‐Y
as
a
photoredox
catalyst
has
been
reported.
The
reaction
takes
place
radical
pathway
evidenced
from
our
experiments
literature.
developed
method
involves
the
utilization
visible‐light
catalysis
for
C‐C
C‐O
bond
abstraction
methylinic
hydrogen
β
‐carbon
well
carbonyl
group
α‐carbon
in
one‐pot
procedure.
present
protocol
shows
significant
advantages
such
application
visible
light
clean
source
energy,
green
solvent,
mild
conditions,
cost
effectiveness,
short
time,
metal
free
synthesis,
easy
operation,
high
atom
economy,
broad
substrate
scope
with
functional
tolerance.
Moreover,
outstanding
yield
product
obtained
up
to
82%.
Chemical Communications,
Год журнала:
2022,
Номер
58(52), С. 7277 - 7280
Опубликована: Янв. 1, 2022
The
photocatalytic
generation
of
α-amino
radicals
is
combined
with
chiral
isothiourea
derived
α,β-unsaturated
acyl
ammonium
intermediates.
reaction
proceeds
VIA
a
[3+2]
radical-polar
crossover
mechanism
to
generate
γ-lactams
in
good
yields
and
enantioselectivities.
enantioselective
radical
conjugate
addition
was
carried
out
under
batch
flow
conditions.
Chemical Communications,
Год журнала:
2021,
Номер
57(57), С. 7047 - 7050
Опубликована: Янв. 1, 2021
A
metal-free
dearomative
[5+2]/[2+2]
cycloaddition
of
1H-indoles
with
ortho-(trimethylsilyl)aryl
triflates
at
room
temperature
was
developed
for
the
synthesis
N-heterocycles.
