The Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
87(21), P. 14125 - 14136
Published: Oct. 18, 2022
A
detailed
mechanistic
study
of
Co(III)-catalyzed
C4-alkenylation
3-acetylindole
(1a)
was
done
based
on
calculations
at
density
functional
theory
(DFT)
and
correlated
wave
function
levels.
The
whole
catalytic
cycle
consists
four
steps:
C-H
activation,
olefin
insertion,
β-hydride
elimination,
regeneration
the
catalyst.
theoretical
results
support
insertion
as
rate-determining
step
leading
to
experimentally
observed
regioselectivity
C4
site
over
C2
site.
By
analysis
three-dimensional
(3D)
geometries
NCl
plot,
preference
for
could
be
attributed
weaker
repulsive
interaction
between
indole
moiety
in
transition
states
former.
reliability
is
further
confirmed
through
DFT
calculation
other
related
derivatives
substrates.
Organic Chemistry Frontiers,
Journal Year:
2024,
Volume and Issue:
11(5), P. 1495 - 1622
Published: Jan. 1, 2024
A
general
and
authoritative
literature
overview
on
Pd-catalyzed
cross-dehydrogenative
coupling
reactions
of
(hetero)arenes
from
the
origins
to
2023,
where
not
only
synthetic
aspects
were
described
but
also
most
relevant
mechanistic
features.
Organic Letters,
Journal Year:
2022,
Volume and Issue:
24(32), P. 6000 - 6005
Published: Aug. 10, 2022
A
Rh-catalyzed
weak
chelation-guided
C4-alkylation
of
indoles
has
been
accomplished
using
cyclopropanols
as
an
alkylating
agent
via
the
cascade
C–H
and
C–C
bond
activation.
The
substrate
scope,
functional
group
tolerance,
late-stage
mutation
drug
molecules
are
important
practical
features.
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(5), P. 988 - 993
Published: Jan. 26, 2024
Palladium-catalyzed
weak-chelation-assisted
C4-selective
nitration
of
indoles
has
been
accomplished
employing
tert-butyl
nitrite
in
the
presence
oxone
under
molecular
oxygen
at
a
moderate
temperature.
Aerobic
conditions,
C4-selectivity,
substrate
scope,
conversion
to
valuable
aminated
indoles,
and
late-stage
natural
product
modifications
are
important
practical
features.
The Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
88(3), P. 1299 - 1318
Published: May 24, 2022
Pd(II)-catalyzed
C-H
arylations
of
free
(NH)
indoles
including
different
carbonyl
directing
groups
on
C3-position
with
aryl
iodides
are
demonstrated.
Importantly,
the
reactions
carried
out
using
same
catalyst
system
without
any
additional
transient
group
(TDG).
In
this
study,
formyl
as
a
gave
C4-arylated
versus
C2-arylation.
Using
system,
functionalization
3-acetylindoles
provided
domino
C4-arylation/3,2-carbonyl
migration
products.
This
transformation
involves
unusual
acetyl
to
C2-position
following
C4-arylation
in
one
pot.
Meanwhile,
could
be
simply
controlled
and
N-protected
afforded
products
group.
Functionalization
indole-3-carboxylic
acid
(or
methyl
ester)
present
Pd(II)-catalyst
resulted
decarboxylation
followed
by
formation
C2-arylated
indoles.
Based
control
experiments
literature,
plausible
mechanisms
proposed.
The
synthetic
utilities
these
acetylindole
derivatives
have
also
been
Remarkably,
acetylindoles
allowed
construction
functionalized
pityiacitrin
(a
natural
product).
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
89(9), P. 6564 - 6574
Published: April 17, 2024
Palladium-catalyzed
weak
chelation-assisted
oxidative
cross-dehydrogenative
coupling
of
arenes
has
been
accomplished.
The
use
medicinally
important
pyridones
as
the
intrinsic
directing
group,
regioselectivity,
2-fold
C–H
activation,
and
late-stage
modification
bioactive
compounds
are
practical
features.
The Journal of Organic Chemistry,
Journal Year:
2023,
Volume and Issue:
88(7), P. 4254 - 4263
Published: March 10, 2023
A
Pd(II)-catalyzed
dehydrogenative
remote
C4–H
coupling
of
indoles
with
unfunctionalized
arenes
at
room
temperature
was
reported.
The
weak
chelating
trifluoroacetyl
group
the
C3-position
served
as
a
directing
for
activation.
Arenes
wide
range
substituents
were
employed
partner
in
cross-coupling
reaction.
ChemCatChem,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 10, 2024
Abstract
Installing
fluoroalkyl
motifs
into
biorelevant
indoles
is
particularly
interesting
due
to
their
ubiquitous
presence
in
drug
molecules.
Herein,
we
demonstrate
the
regioselective
C4
fluoroalkoxylation
of
using
fluoroalcohols
via
palladium‐catalyzed
chelation‐assisted
C─H
activation.
The
weak
chelating
benzoyl
moiety
at
C3
position
acts
as
a
directing
group
for
remote
C(4)─H
diversely
substituted
indoles.
This
methodology
demonstrates
high
level
regioselectivity
and
tolerates
range
crucial
functional
groups,
yielding
diverse
trifluoroalkoxylated
moderate
good
yields.
Removal
directing/protecting
groups
further
functionalization
established
synthetic
utility
methodology.
A
preliminary
mechanistic
investigation
conducted
by
isolating
palladacycle
intermediate
performing
deuterium
scrambling
study.
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 20, 2024
The
Rh(III)-catalyzed
indole
C4-H
bond
addition
to
nitroalkenes
is
disclosed
under
mild
and
redox-neutral
reaction
conditions,
offering
straightforward
access
various
4-(2-nitroalkyl)indoles
(34
examples)
with
excellent
chemo-
regioselectivity.
Furthermore,
late-stage
diversifications
mechanistic
studies
were
also
performed.
European Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
2022(31)
Published: July 16, 2022
Abstract
Aerobic
oxidative
coupling
is
a
dehydrogenative
organic
transformation
in
which
molecular
oxygen
acts
as
re‐oxidant
for
the
catalyst
system.
Pd
has
emerged
one
of
most
popular
transition
metal
catalysts
such
reactions.
Combinations
with
other
can
also
provide
effective
catalytic
cycles
together
highly
atom‐
and
step‐economical
transformations.
A
synergic
system
promote
reactions
high
degree
efficiency
based
on
re‐oxidation
step
exhibiting
improved
kinetics
two
electrons
are
transferred
from
another
metal.
This
occurs
conjunction
lower
energy
barrier
than
that
associated
direct
by
oxygen.
review
highlights
recent
developments
aerobic
catalyzed
combinations
metals.
Highlighted
include
C−C
bond
formation
arylation
arenes,
heteroarenes,
alkenes
C−N
C−O
formations
unsaturated
hydrocarbons
alkenes,
1,3‐dienes
allenes.
Moreover,
mechanistic
insights
into
these
experimental,
computational
optical
studies
detailed.
Synlett,
Journal Year:
2022,
Volume and Issue:
34(07), P. 759 - 776
Published: Aug. 19, 2022
Abstract
C4-Functionalized
indole
scaffolds
are
ubiquitous
in
natural
products,
bioactive
compounds,
and
pharmaceuticals.
Much
effort
has
thus
been
made
to
develop
effective
synthetic
strategies
for
C4
functionalization
of
the
core.
Among
them,
chelation-assisted
approaches
using
transition-metal
catalysis
C4-selective
C–H
is
attractive.
This
account
highlights
progress
C4-carbon–carbon
bond
formation
directing-group-assisted
transition-metal-catalyzed
(up
May
2022).
These
studies
have
performed
Ru,
Rh,
Pd
Ir-based
catalytic
systems,
while
attention
focused
on
use
first-row
abundant
systems.
1
Introduction
2
Alkylation
3
Acylation
4
Alkenylation
5
Alkynylation
6
Allylation
7
Annulation
8
Arylation
9
Conclusion
Outlook
