Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(14), С. 2377 - 2384
Опубликована: Июнь 21, 2023
Abstract
N
,
’‐Diaryl
ethylenediamines
are
common
feedstocks
in
organic
synthesis
and
important
structural
motifs
medicinal
chemistry.
Whereas
the
C−N
formation
reactions
based
on
anilines
aryl
halides
most
direct
methods
to
access
’‐diaryl
ethylenediamines,
photocatalytic
synthetic
version
remains
undeveloped.
Herein
we
describe
dual
nickel/photoredox‐catalyzed
amination
reaction
using
nitroarenes
trimethylamine
as
substrates.
This
cascade
transformation
hinges
multiple
C−C
coupling
events
nitrogen
radical
α‐aminomethyl
derived
from
nitroarene
trimethylamine,
respectively.
A
variety
of
‐formyl
can
be
obtained
under
protocol.
Subsequent
hydrolysis
offers
for
further
derivatizations.
ACS Catalysis,
Год журнала:
2024,
Номер
14(10), С. 8005 - 8012
Опубликована: Май 9, 2024
We
report
intra-
and
intermolecular
γ-amino
C(sp3)–H
functionalization
of
aliphatic
amines
using
a
vinylsulfone-based
HAT
(hydrogen
atom
transfer)
auxiliary
triple
catalysis,
which
is
composed
photoredox,
cobalt,
Brønsted
acid
catalysts
under
visible
light
irradiation.
The
process
accomplishes
four
elementary
steps:
(i)
electrophilic
carbon-centered
radical
formation
on
the
via
MHAT
(metal
hydride
hydrogen
reaction,
(ii)
generation
through
1,6-HAT
(iii)
single-electron
oxidation
to
carbocation
equivalents,
(iv)
nucleophilic
substitution
with
internal
or
external
nucleophiles.
As
result,
this
afforded
γ-amino-functionalized
products,
such
as
azetidines,
1,3-diamine,
1,3-aminoalcohol
derivatives.
Abstract
New
methods
and
strategies
for
the
direct
oxidation
of
benzylic
C−H
bonds
are
highly
desirable,
owing
to
importance
ketone
motifs
in
significant
organic
transformations
synthesis
valuable
molecules,
including
pharmaceuticals,
pesticides,
fine
chemicals.
Herein,
we
describe
an
electrochemical
strategy
ketones
using
MeOH
as
oxygen
source.
Inexpensive
safe
KBr
serves
both
electrolyte
a
bromide
radical
precursor
reaction.
This
transformation
also
offers
several
advantages
such
mild
conditions,
broad
functional
group
tolerance,
operational
simplicity.
Mechanistic
investigations
by
control
experiments,
scavenging
electron
paramagnetic
resonance
(EPR),
kinetic
studies,
cyclic
voltammetry
(CV),
in‐situ
Fourier
transform
infrared
(FTIR)
spectroscopy
support
pathway
involving
formation
benzyl
methyl
ether
via
hydrogen
atom
transfer
(HAT)
single‐electron
(SET).
The
practical
application
our
is
highlighted
successful
five
namely
lenperone,
melperone,
diphenhydramine,
cinnarizine,
flunarizine.
ACS Omega,
Год журнала:
2024,
Номер
9(24), С. 26708 - 26718
Опубликована: Июнь 4, 2024
Y–H
bond
functionalization
has
always
been
the
focus
of
research
interest
in
area
organic
synthesis.
Direct
hydrogen
atom
transfer
(HAT)
from
is
one
most
efficient
and
practical
methods
to
activate
bond.
Recently,
nitrogen
centered
radical
cations
were
broadly
utilized
as
H-abstraction
catalysts
bonds
via
HAT
process.
As
a
type
catalyst,
H-affinity
significant
thermodynamic
parameter
quantitatively
evaluate
potentials
cations.
In
this
work,
pKa
values
120
protonated
N-containing
compounds
acetonitrile
(AN)
are
predicted,
H-affinities
AN
derived
reduction
using
Hess'
law.
This
work
focuses
on
abilities
enrich
molecule
library
novel
or
H-abstractors
provides
valuable
guidelines
for
application
functionalization.
Nature Communications,
Год журнала:
2024,
Номер
15(1)
Опубликована: Авг. 8, 2024
Site-selective
C(sp3)–H
arylation
is
an
appealing
strategy
to
synthesize
complex
arene
structures
but
remains
a
challenge
facing
synthetic
chemists.
Here
we
report
the
use
of
photoredox-mediated
hydrogen
atom
transfer
(HAT)
catalysis
accomplish
site-selective
α-C(sp3)–H
dialkylamine-derived
ureas
through
1,4-radical
aryl
migration,
by
which
wide
array
benzylamine
motifs
can
be
incorporated
medicinally
relevant
systems
in
late-stage
installation
steps.
In
contrast
previous
efforts,
this
C–H
protocol
exhibits
specific
site-selectivity,
proforming
predominantly
on
sterically
more-hindered
secondary
and
tertiary
α-amino
carbon
centers,
while
functionalization
less-hindered
N-methyl
group
effectively
circumvented
most
cases.
Moreover,
diverse
range
multi-substituted
piperidine
derivatives
obtained
with
excellent
diastereoselectivity.
Mechanistic
computational
studies
demonstrate
that
rate-determining
step
for
methylene
initial
H
abstraction,
whereas
radical
ipso
cyclization
bears
highest
energy
barrier
functionalization.
The
relatively
lower
activation
free
energies
compared
methylic
bond
lead
exceptional
site-selectivity.
authors
migration.
A
photocatalytic
hydroamidomethylation
of
azobenzenes
with
N,N-dimethylamides
has
been
developed.
Using
tetrabutylammonium
decatungstate
(TBADT)
as
a
photocatalyst,
an
array
and
reacted
smoothly
under
visible
light
irradiation,
affording
previously
unreported
N-amidomethyl-N,N′-diarylhydrazines
in
generally
high
yields.
Mechanistic
studies
indicate
that
the
reaction
is
enabled
by
TBADT-mediated
hydrogen
atom
transfer
(HAT)
photocatalysis.
This
work
fundamentally
different
from
reported
N,N-dimethylformamide
azobenzenes.
Organic Letters,
Год журнала:
2023,
Номер
25(6), С. 987 - 991
Опубликована: Фев. 3, 2023
Piperazines
are
important
heterocycles
in
drug
compounds.
We
report
the
asymmetric
synthesis
of
arylpiperazines
by
photocatalytic
decarboxylative
arylation
(metallaphotoredox
catalysis)
then
kinetic
resolution
using
n-BuLi/(+)-sparteine.
This
gave
a
range
piperazines
with
very
high
enantioselectivities.
Further
functionalizations
enantioenriched
2,2-disubstituted
piperazines,
and
either
N-substituent
can
be
removed
selectively.
Late-stage
piperazine
derivatives
were
demonstrated,
including
compound
glycogen
synthase
kinase
(GSK)-3β
inhibitor
activity
potential
for
treating
Alzheimer's
disease.
ACS Catalysis,
Год журнала:
2024,
Номер
14(19), С. 14574 - 14585
Опубликована: Сен. 16, 2024
A
class
of
in-situ
generated
Lewis
acid
(LA)
activated
acridine
complexes
is
reported,
which
act
as
potent
photochemical
catalysts
for
the
oxidation
a
variety
protected
secondary
amines.
Acridine/LA
exhibit
tunable
excited
state
reduction
potentials
ranging
from
+2.07
to
2.38
V
vs.
SCE.
The
ytterbium
triflate
complex
3,6-di-t-butyl-9-mesitylacridine
catalyzes
Giese-type
reaction
Boc-protected
amines
with
challenging
conjugate
acceptors
such
acrylates,
that
are
inaccessible
analogous
acridinium
(t-Bu-Mes-Acr⊕)
catalyzed
reaction.
mechanism
this
was
investigated
using
suite
physical
organic
probes
including
intramolecular
13C
kinetic
isotope
effects
(KIEs),
variable
time
normalization
analysis
(VTNA)
kinetics,
determination
redox
potentials,
and
computational
studies.
In
by
t-Bu-Mes-Acr⊕,
mechanistic
studies
consistent
single-electron
transfer
(SET)
ground-state
reduced
t-Bu-Mes-Acr•
α-keto
radical
intermediate
first
irreversible
step
in
catalytic
cycle.
Intriguingly,
we
find
acridine/LA
better
ground
reductants
(-0.72
-0.74
vs
SCE)
relative
(-0.59
predict
increased
substrate
reactivity
stems
lower
energy
barrier
key
SET
event.
Advanced Synthesis & Catalysis,
Год журнала:
2023,
Номер
365(14), С. 2377 - 2384
Опубликована: Июнь 21, 2023
Abstract
N
,
’‐Diaryl
ethylenediamines
are
common
feedstocks
in
organic
synthesis
and
important
structural
motifs
medicinal
chemistry.
Whereas
the
C−N
formation
reactions
based
on
anilines
aryl
halides
most
direct
methods
to
access
’‐diaryl
ethylenediamines,
photocatalytic
synthetic
version
remains
undeveloped.
Herein
we
describe
dual
nickel/photoredox‐catalyzed
amination
reaction
using
nitroarenes
trimethylamine
as
substrates.
This
cascade
transformation
hinges
multiple
C−C
coupling
events
nitrogen
radical
α‐aminomethyl
derived
from
nitroarene
trimethylamine,
respectively.
A
variety
of
‐formyl
can
be
obtained
under
protocol.
Subsequent
hydrolysis
offers
for
further
derivatizations.
