Advanced Science,
Journal Year:
2024,
Volume and Issue:
11(12)
Published: Jan. 17, 2024
Abstract
An
unprecedented
enantioselective
protonation
reaction
enabled
by
photoredox
catalytic
radical
coupling
is
developed.
Under
cooperative
dicynopyrazine‐derived
chromophore
(DPZ)
as
a
photosensitizer
and
chiral
phosphoric
acid
catalyst,
Hantzsch
ester
sacrificial
reductant,
the
transformations
between
α‐substituted
enones
cyanoazaarenes
or
2‐(chloromethyl)azaaren‐1‐iums
can
proceed
tandem
reduction,
coupling,
process
efficiently.
Two
classes
of
pharmaceutically
important
enantioenriched
azaarene
variants,
which
contain
synthetically
versatile
ketone‐substituted
tertiary
carbon
stereocenter
at
β
‐
γ
‐position
azaarenes,
are
synthesized
with
high
yields
ees.
SmartMat,
Journal Year:
2021,
Volume and Issue:
2(1), P. 17 - 32
Published: Feb. 16, 2021
Chirality
communications
between
inorganic
and
organic
compounds
bridge
the
gap
different
materials.
The
transfer
is
mainly
realized
by
material
hybridization
andasymmetric
synthesis,
while
recognition
usually
carried
out
in
form
of
enantioselective
adsorption
organics
on
inorganics.
can
enlarge
number
chiral
materials,
which
may
lead
to
new
applications
many
fields.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(9), P. 4114 - 4123
Published: Feb. 15, 2022
Whereas
photoinduced,
copper-catalyzed
couplings
of
nitrogen
nucleophiles
with
alkyl
electrophiles
have
recently
been
shown
to
provide
an
attractive
approach
achieving
a
variety
enantioselective
C–N
bond
constructions,
mechanistic
studies
these
transformations
lagged
the
advances
in
reaction
development.
Herein
we
insight
into
previously
reported
enantioconvergent
coupling
carbazole
nucleophile
racemic
tertiary
α-haloamide
electrophile.
Building
on
isolation
copper(II)
model
complex
whose
EPR
parameters
serve
as
guide,
independently
synthesize
two
key
intermediates
proposed
catalytic
cycle,
metalloradical
(L*CuII(carb′)2)
(L*
=
monodentate
chiral
phosphine
ligand;
carb′
carbazolide
ligand),
well
α-amide
organic
radical
(R·);
generation
and
characterization
R·
was
guided
by
DFT
calculations,
which
suggested
that
it
would
be
stable
homocoupling.
Continuous-wave
(CW)
pulse
studies,
along
corresponding
are
among
techniques
used
characterize
reactive
radicals.
We
establish
radicals
do
indeed
combine
furnish
product
good
yield
significant
enantiomeric
excess
(77%
yield,
55%
ee),
thereby
supporting
chemical
competence
intermediates.
calculations
consistent
initially
binding
via
dative
interaction
from
closed-shell
carbonyl
oxygen
atom
radical,
positions
α-carbon
for
direct
copper(II)-bound
N
atom,
generate
enantioselectivity,
without
formation
alkylcopper(III)
intermediate.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(36), P. 20141 - 20148
Published: Aug. 28, 2023
Chemodivergent
synthesis
has
been
achieved
in
asymmetric
photocatalysis.
Under
a
dual
catalyst
system
consisting
of
chiral
phosphoric
acid
and
DPZ
as
photosensitizer,
different
inorganic
bases
enabled
the
formation
two
sets
valuable
products
from
three-component
radical
tandem
transformations
2-bromo-1-arylenthan-1-ones,
styrenes,
quinoxalin-2(1H)-ones.
The
key
to
success
was
distinct
pKa
environment,
which
radicals
that
formed
on
quinoxalin-2(1H)-one
rings
after
addition
processes
underwent
either
single-electron
oxidation
or
reduction.
In
addition,
this
work
represents
first
use
quinoxalin-2(1H)-ones
photoredox
catalysis.
Advanced Science,
Journal Year:
2024,
Volume and Issue:
11(12)
Published: Jan. 17, 2024
Abstract
An
unprecedented
enantioselective
protonation
reaction
enabled
by
photoredox
catalytic
radical
coupling
is
developed.
Under
cooperative
dicynopyrazine‐derived
chromophore
(DPZ)
as
a
photosensitizer
and
chiral
phosphoric
acid
catalyst,
Hantzsch
ester
sacrificial
reductant,
the
transformations
between
α‐substituted
enones
cyanoazaarenes
or
2‐(chloromethyl)azaaren‐1‐iums
can
proceed
tandem
reduction,
coupling,
process
efficiently.
Two
classes
of
pharmaceutically
important
enantioenriched
azaarene
variants,
which
contain
synthetically
versatile
ketone‐substituted
tertiary
carbon
stereocenter
at
β
‐
γ
‐position
azaarenes,
are
synthesized
with
high
yields
ees.
