Weak‐Chelation Assisted Regioselective Indole C(4)‐Alkynylation via Six‐Membered Cobaltacycle Intermediate
Advanced Synthesis & Catalysis,
Год журнала:
2024,
Номер
366(6), С. 1341 - 1347
Опубликована: Янв. 13, 2024
Abstract
Herein
a
regioselective
indole
C4‐alkynylation
has
been
uncovered
utilizing
an
earth‐abundant
cobalt(III)‐catalyst.
For
this
process,
(bromoethynyl)benzene
was
used
as
alkynylating
agent.
Also,
after
screening
various
amide‐protected
chelating
groups
we
found
dimethyl‐amide
is
optimal
for
the
in‐situ
generation
of
cobaltacycle
intermediate.
The
six‐membered
intermediate
detected
through
high‐resolution
mass
spectrometry
HRMS,
which
key
conversion.
Further,
mechanistic
studies
were
performed
such
KIE
experiments,
and
reactions
with
radical
scavengers,
based
on
results
plausible
mechanism
proposed.
Moreover,
to
show
application
methodology,
product
oxidized
diketone,
monoketone,
alkene,
alkane
further
derivatized
tricycle
derivative,
core
structure
many
natural
products.
Язык: Английский
Uncovering the Reactivity of Cobalt‐Catalyst Towards Regioselective Hydroarylation of 1,6‐Diyne via Weak‐Chelation Assisted C−H Bond Activation
Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(12), С. 1977 - 1982
Опубликована: Июнь 2, 2023
Abstract
Herein,
we
report
the
reactivity
of
cobalt(III)‐catalyst
towards
hydroarylative
functionalization
1,6‐diyne,
which
has
never
been
explored
before.
The
N
‐aryl
lactam
is
prime
substrate
that
undergoes
sp
2
C−H
bond
activation.
C−Co(III)
formation
occurs
through
weakly
coordinating
group.
reaction
mechanism
reveals
in‐situ
a
six‐membered
cobaltacycle
further
with
1,6‐diyne.
Also,
radical
quenching
experiments
suggest
involvement
ionic
pathway
for
this
conversion.
In
addition,
hydrogen
scrambling
and
kinetic
isotope
support
proposed
mechanism.
A
wide
range
electronically
biased
substrates
reacting
partners
work
well
method
in
highly
atom‐economical
fashion.
Язык: Английский
Co(III)-Catalyzed C6-Selective C–H Activation/Pyridine Migration of 2-Pyridones with Propiolates
Yuelu Zhu,
Na Zhao,
Xin-Long Fu
и другие.
Organic Letters,
Год журнала:
2023,
Номер
unknown
Опубликована: Дек. 21, 2023
A
versatile
Co(III)-catalyzed
C6-selective
C–H
activation/pyridine
migration
of
2-pyridones
with
available
propiolates
as
coupling
partners
was
demonstrated.
This
method
features
high
atom
economy,
excellent
regioselectivity,
and
good
functional
group
tolerance
by
employing
an
inexpensive
Co(III)
catalyst
under
mild
reaction
conditions.
Moreover,
gram-scale
synthesis
late-stage
modifications
pharmaceuticals
were
performed
to
prove
the
effectiveness
these
synthetic
approaches.
Язык: Английский
Co(III) or Ru(II)-Catalyzed Selective C–H Alkynylation of 2-Pyridones and Their Derivatives with Bromoalkynes
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 5, 2024
We
successfully
reported
selective
C–H
alkynylation
of
2-pyridones
with
bromoalkynes
under
the
catalysis
Co(III)
or
Ru(II).
The
reaction
used
easily
accessible
instead
high-valent
iodine
alkynes.
There
is
a
broad
substrate
scope
good
yields.
In
addition,
2-pyridone
can
be
as
weakly
directing
group
for
proximal
aryl
bond.
This
method
offers
an
efficient
approach
synthesizing
diverse
derivatives,
yielding
alkynylated
products
up
to
95%
yield
(>40
examples).
Язык: Английский