The Chemical Record,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 19, 2024
N-heterocyclic
carbene
(NHC)
organocatalysis
has
been
developed
as
a
powerful
tool
in
modern
synthetic
chemistry.
NHC
catalytic
activation
of
ynals
and
alkynoic
acid
derivatives
provided
versatile
reactions
that
involve
acetylenic
Breslow
and/or
acylazolium
key
intermediates,
diverse
transformations
have
established
for
access
to
molecules
with
unique
skeletons
efficient
fashions.
Herein
we
summarize
the
recent
achievements
NHC-catalyzed
involving
intermediates.
Different
belonging
three
modes,
including
(1)
conjugate
additions
derived
α,β-unsaturated
(2)
β-umpolung
via
(3)
are
emphasized
examples
plausible
mechanisms
cited
guide
better
understanding.
Chemistry - An Asian Journal,
Journal Year:
2024,
Volume and Issue:
19(9)
Published: March 7, 2024
N-Heterocyclic
carbenes
(NHCs)
catalysts
have
been
employed
as
effective
tools
in
the
development
of
various
reactions,
which
made
notable
contributions
developing
diverse
reaction
modes
and
generating
significant
functionalized
molecules.
This
review
provides
an
overview
recent
advancements
chemo-
regioselective
activation
different
aldehydes
using
NHCs,
categorized
into
five
parts
based
on
modes.
A
brief
conclusion
outlook
is
provided
to
stimulate
novel
for
accessing
functional
The Journal of Physical Chemistry A,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 5, 2025
A
theoretical
study
on
the
mechanism,
regioselectivity,
and
enantioselectivity
of
NHC-catalyzed
dearomatizing
annulation
benzoxazoles
with
enals
has
been
conducted
using
density
functional
theory
calculations.
Our
calculated
results
indicate
that
favored
mechanism
occurs
through
eight
reaction
steps:
initial
binding
NHC
to
enals,
followed
by
formation
Breslow
intermediate
via
proton
transfer.
Subsequent
oxidation
generates
α,β-unsaturated
acylazolium
intermediate,
which
can
undergo
Michael
addition
benzoxazoles.
Sequential
protonation/deprotonation/cyclization
produces
six-membered
cyclic
undergoes
catalyst
elimination,
leading
final
product.
DABCO·H+
was
found
play
important
roles
in
transfer
cyclization.
Without
DABCO·H+,
energy
barrier
up
44.2
kcal/mol
for
step
2
is
too
high
be
accessible.
With
corresponding
value
lowered
18.6
kcal/mol.
The
cyclization
7.4
DABCO·H+.
determines
both
regioselectivity.
According
NCI
analysis,
controlled
strong
interactions
(such
as
C-H···O,
C-H···N,
π···π)
between
We
also
discuss
solvent
substituent
effects
role
NHC.
mechanistic
insights
obtained
present
would
help
improving
current
systems
or
designing
new
synthetic
routes.
Asian Journal of Organic Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 3, 2025
Abstract
NHC‐Catalyzed
enantioselective
conversion
of
ynals
remains
challenging
through
nucleophilic
NHC‐allenolate
intermediates.
Herein,
we
present
an
NHC‐catalyzed
highly
asymmetric
intramolecular
[3+2]
annulation
cyclohexadienone‐tethered
ynals.
This
reaction
enables
a
rapid
and
efficient
construction
6,5,5‐tricyclic
frameworks
bearing
three
contiguous
stereocenters
in
excellent
enantioselectivities.
Additionally,
the
synthetic
utility
is
elaborated
gram‐scale
experiment
several
downstream
transformations.
Organic Chemistry Frontiers,
Journal Year:
2024,
Volume and Issue:
11(23), P. 6627 - 6641
Published: Jan. 1, 2024
Blue
to
yellow-emitting
2-oxo-pyrano[2,3-
b
]indolizines,
which
are
efficiently
prepared
in
two
steps
from
pyridinium
salts,
have
strong
emission
across
the
solvent
polarity
scale.
Chemical Society Reviews,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 18, 2024
This
tutorial
review
provides
an
overview
of
various
important
structural
features
and
reactivity
modes
NHCs
delves
deep
into
the
recent
advances
in
NHC-organocatalysis.
The Journal of Physical Chemistry A,
Journal Year:
2024,
Volume and Issue:
128(22), P. 4483 - 4492
Published: May 24, 2024
To
elucidate
the
mechanism
and
origins
of
chemo-
enantioselectivities
reaction
between
aliphatic
aldehydes
hydrazones
catalyzed
by
triazolium-derived
NHC,
density
functional
theory
computations
have
been
performed.
According
to
our
calculated
results,
whole
catalytic
cycle
for
formation
dihydropyridazinones
proceeds
via
initial
nucleophilic
addition
NHC
an
aldehyde,
followed
concerted
intramolecular
proton
transfer
C-Cl
bond
cleavage.
Subsequent
deprotonation
generates
enolate
intermediate.
The
intermediate
then
undergoes
1,4-addition
hydrazone
construct
a
new
carbon-carbon
bond.
following
ring-closure
would
lead
six-membered
ring
intermediate,
which,
upon
release
affords
final
product
dihydropyridazinone.
computation
results
reveal
that
is
significantly
promoted
Brønsted
acid
DIPEA·H
The Chemical Record,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 17, 2024
Abstract
As
a
significant
variant
of
the
Michael
reaction,
1,6‐addition
reaction
has
undergone
considerable
development
over
past
decade.
This
effective
strategy
enables
synthesis
variety
novel
and
potentially
bioactive
functional
molecules.
In
this
review,
we
summarize
recent
progress
in
NHC‐catalyzed
reactions,
highlighting
their
efficiency
rapid
complex
We
also
provide
our
perspectives
on
future
dynamic
highly
active
research
area.
