The Chemical Record,
Год журнала:
2023,
Номер
23(7)
Опубликована: Март 14, 2023
Abstract
Over
the
recent
decades,
due
to
special
electronic
characteristics
and
diverse
reactivities,
N‐heterocyclic
carbene
(NHC)
has
received
significant
interest
in
organocatalyzed
reactions.
The
formation
of
Breslow
intermediates
by
NHC
can
convert
into
acyl
anion
equivalent,
enolates,
homoenolate,
azolium,
vinyl
enolate
etc
.,
cycloaddition
reactions
these
species
attracted
lots
attention.
In
this
review,
we
focus
on
summry
development
NHC‐activation
carbonyl
carbon
(or
imine
carbon)
situ
,
α‐,
β‐,
γ‐,
beyond,
reaction
species.
Asian Journal of Organic Chemistry,
Год журнала:
2023,
Номер
12(9)
Опубликована: Июль 25, 2023
Abstract
The
reactivity
of
N‐Heterocyclic
carbene
(NHC)‐bound
alkynyl
acyl
azoliums
is
underexplored
in
chemistry.
We
herein
reported
an
NHC‐catalyzed
[3+3]
annulation
with
β
‐keto
esters.
strategy
features
mild
reaction
conditions
and
exhibits
broad
substrates
scope,
delivering
a
wide
range
tri‐substituted
α
‐pyrones
moderate
to
excellent
yields
(up
95%).
This
approach
extends
the
esters
binucleophiles.
Molecules,
Год журнала:
2022,
Номер
27(22), С. 7990 - 7990
Опубликована: Ноя. 17, 2022
N-heterocyclic
carbene
(NHC)
has
been
widely
used
as
an
organocatalyst
for
both
umpolung
and
non-umpolung
chemistry.
Previous
works
mainly
focus
on
species
including
Breslow
intermediate,
azolium
enolate
homoenolate
alkenyl
acyl
etc.
Notably,
the
NHC-bound
alkynyl
emerged
effective
intermediate
to
access
functionalized
cyclic
molecular
skeleton
until
very
recently.
In
this
review,
we
summarized
generation
reactivity
of
intermediates,
which
covers
efforts
advances
in
synthesis
achiral
axially
chiral
scaffolds
via
intermediates.
particular,
mechanism
related
is
discussed
detail.
The Chemical Record,
Год журнала:
2023,
Номер
23(7)
Опубликована: Июнь 12, 2023
Abstract
The
ease
with
which
simple
starting
materials
can
be
transformed
into
highly
functionalized
products
has
made
oxidative
N‐heterocyclic
carbene
(NHC)
catalysis
an
area
of
significant
interest.
However,
the
use
stoichiometric
amounts
high
molecular
weight
oxidants
in
most
reactions
generates
undesired
equivalent
amount
waste.
To
address
this
issue,
oxygen
as
terminal
oxidant
NHC
been
developed.
Oxygen
is
attractive
due
to
its
low
cost,
weight,
and
ability
generate
water
sole
by‐product.
challenging
a
reagent
organic
synthesis
unreactive
ground
state,
often
requires
run
at
temperatures
results
formation
kinetic
side‐products.
This
review
covers
development
aerobic
catalysis,
including
NHC‐catalyzed
oxygen,
strategies
for
activation,
selectivity
issues
under
conditions.