A
nickel-catalyzed
reductive
1,4-alkylacylation
of
1,3-enynes
has
been
established
using
nonactivated
tertiary
alkyl
bromides
and
aromatic
anhydrides
as
dual
electrophiles.
This
protocol
enables
efficient
assembly
tetrasubstituted
allenyl
ketones
with
high
chemo-
regioselectivity.
Mechanistic
insights
reveal
the
radical
relay
process
involving
synergistic
interactions
nickel
zinc.
The
ketone
products
serve
modular
building
blocks,
particularly
for
constructing
fully
carbon-substituted
furans
via
Au-catalyzed
cycloisomerization
selective
1,2-aryl
migration,
enhancing
synthetic
practicality.
Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(9), С. 1332 - 1384
Опубликована: Март 14, 2023
Abstract
Conjugated
and
non‐conjugated
allenones
appear
as
recurring
motifs
in
organic
synthesis,
natural
products
mechanistic
investigations
showing
unique
properties
applications.
The
ability
of
to
build
cycles
has
provided
a
direct
access
strained
systems,
medium‐sized
rings,
arenes,
heterocycles
complex
polycycles.
In
addition,
have
served
models
catalysis.
critic
compilation
herein
presented
will
provide
an
exhaustive
overview
the
synthetic
possibilities
may
offer,
which
certainly
inspire
our
community
their
search
more
efficient
methodologies,
preparation
biological
pharmaceutical
targets,
improve
knowledge
theoretical
chemistry.
Great
part
this
review
discuss
aspects,
catalysis
innovation
insights
chemical
transformations
implying
allenone
motif.
many
examples
on
total
synthesis
pharmacologically
active
compounds
be
described.
We
hope
that
attractive
chemistry,
catalysis,
medicinal
chemistry
communities.
magnified
image
Abstract
Radical
N
‐heterocyclic
carbene
(NHC)
organocatalysis
has
progressed
significantly
in
recent
years,
enabling
various
incredible
transformations.
However,
prefunctionalized
substrates
bearing
a
redox
functionality
were
always
required.
As
result,
the
direct
functionalization
of
aliphatic
C−H
bonds
simple
remains
challenge.
This
situation
was
changed
once
hydrogen
transfer
atom
(HAT)
strategy
successfully
applied
radical
NHC
catalysis
very
recently.
concept
paper
focused
on
discussion
merging
with
classical
intramolecular
1,5‐HAT
process.
Moreover,
unprecedented
application
intermolecular
HAT
is
highlighted
as
novel
model
showing
great
synthetic
promise.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
10(4), С. 1047 - 1055
Опубликована: Янв. 1, 2023
Visible
light-mediated
NHC
and
photoredox
co-catalyzed
radical
1,2-sulfonylacylation
of
allenes
via
cross-coupling
between
an
allyl
NHC-stabilized
acyl
radical.
Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(13), С. 2092 - 2125
Опубликована: Май 16, 2023
Abstract
Fluorinated
alkyl
iodides
serve
as
a
convenient
and
inexpensive
source
of
fluoroalkyl
radicals
that
can
readily
undergo
addition
to
the
C−C
unsaturated
bonds
alkynes
alkenes
which
is
foundation
for
variety
useful
synthetic
protocols.
Since
2010
this
field
has
witnessed
huge
progress
in
several
respects.
First
portfolio
fluorinated
was
extended
beyond
only
simple
perfluoroalkyl
(C
n
F
2n+1
I).
In
particular,
employment
iododifluoro−methyl‐
carbonyls
phosphonates
enabled
facile
installation
medicinally
relevant
difluoromethylene
motif.
Secondly,
from
conceptual
point
view,
novel
strategies
activation
towards
radical
formation
have
been
introduced,
relying
on
electron
donor‐acceptor
(EDA)
complexes,
photoredox
catalysis,
frustrated
Lewis
pairs
transition
metal
complementing
prior
approaches
based
heat
UV
induced
C−I
homolysis,
initiators,
transfer
processes.
Based
these
range
fluoroalkylative
transformations
systems
added
classical
iodoperfluoroalkylation.
Broadly
applicable
protocols
fluoroalkylation
hydrofluoroalkylation,
well
more
sophisticated,
complexity‐building
methods
fluoroalkylation‐annulation
tandem
multicomponent
fluoroalkylations
with
concomitant
another
functionality
recently
disclosed.
This
review
summarizes
achieved
since
reactivity
emphasis
placed
above‐mentioned
advances.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
10(7), С. 1669 - 1674
Опубликована: Янв. 1, 2023
N
-Heterocyclic
carbene-catalyzed
difluorocyclopropanation
of
alkenes
with
aldehydes
and
CF
2
Br
for
a
facile
efficacious
synthesis
new
class
functionalized
gem
-difluorocyclopropanes
bearing
acyl
groups
was
developed.
Synthesis,
Год журнала:
2022,
Номер
54(15), С. 3307 - 3316
Опубликована: Апрель 11, 2022
Abstract
NHC-catalyzed
radical
cross-coupling
reactions
have
been
recently
developed;
they
provide
an
efficient
method
to
access
ketones
from
aldehydes
or
carboxylic
acid
derivatives
with
sp3-hybridized
carbon
precursors.
This
reaction
has
indirectly
solved
the
limitations
in
scope
of
coupling
partners
NHC
umpolung
catalyzed
aldehydes.
In
this
short
review,
we
present
some
recent
advances
reactions,
a
focus
on
construction
C–C(CO)
bond.
1
Introduction
2
Oxidative
Generation
NHC-Derived
Ketyl
Radical
2.1
NHPI
Redox-Active
Esters
2.2
Katritzky
Pyridinium
Salts
2.3
Alkyl
Halides
2.4
Aryl
2.5
Compounds
Containing
N–O
Bond
2.6
Diazo
2.7
Others
3
Reductive
3.1
Hantzsch
3.2
Sulfinates
3.3
Electron-Rich
Arenes
3.4
Amines
3.5
Organoborane
Reagents
4
Conclusion
Abstract
During
the
past
decades,
N
‐heterocyclic
carbene
(NHC)‐catalyzed
reactions
have
emerged
as
a
versatile
tool
in
synthetic
chemistry.
In
particular,
NHC‐catalyzed
cross‐coupling
reaction
has
been
significantly
developed
many
respects,
including
new
development
and
mechanistic
investigation.
This
concept
article
presents
recent
advances
towards
direct
of
aldehydes
with
alkyl
halides
enabled
by
NHC
organocatalysis.
