Research Square (Research Square),
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 19, 2024
Abstract
The
activation
of
C−C
bond
benzocyclobutenones
under
mild
reaction
conditions
remains
a
challenge.
We
herein
report
photoinduced
catalyst-free
regio-specific
C1−C8
cleavage
benzocyclobutenones,
enabling
the
generation
versatile
ortho-quinoid
ketene
methides
for
aza-[4
+
2]-cycloaddition
with
imines,
which
offers
facile
route
to
isoquinolinone
derivatives,
including
seven
family
members
protoberberine
alkaloids,
gusanlung
A,
B,
D,
8-oxotetrahydroplamatine,
tetrahydrothalifendine,
tetrahydropalmatine,
and
xylopinine.
Furthermore,
catalytic
enantioselective
version
this
strategy
was
realized
by
merging
synergistic
photocatalysis
chiral
Lewis
acid
catalysis.
Mechanistic
studies
provided
compelling
evidence
rationalize
photoisomerization/cycloaddition
cascade
process.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(15), С. 10857 - 10867
Опубликована: Апрель 8, 2024
The
asymmetric
cross-coupling
of
unsaturated
bonds,
hampered
by
their
comparable
polarity
and
reactivity,
as
well
the
scarcity
efficient
catalytic
systems
capable
diastereo-
enantiocontrol,
presents
a
significant
hurdle
in
organic
synthesis.
In
this
study,
we
introduce
highly
adaptable
photochemical
cobalt
catalysis
framework
that
facilitates
chemo-
stereoselective
reductive
cross-couplings
between
common
aldehydes
with
broad
array
carbonyl
iminyl
compounds,
including
N-acylhydrazones,
aryl
ketones,
aldehydes,
α-keto
esters.
Our
methodology
hinges
on
synergistic
mechanism
driven
photoredox-induced
single-electron
reduction
subsequent
radical–radical
coupling,
all
precisely
guided
chiral
catalyst.
Various
optically
enriched
β-amino
alcohols
unsymmetrical
1,2-diol
derivatives
(80
examples)
have
been
synthesized
good
yields
(up
to
90%
yield)
high
stereoselectivities
>20:1
dr,
99%
ee).
Of
particular
note,
approach
accomplishes
unattainable
transformations
disparate
partners
without
reliance
any
external
photosensitizer,
thereby
further
emphasizing
its
versatility
cost-efficiency.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(33), С. 23457 - 23466
Опубликована: Июль 12, 2024
Developing
novel
strategies
for
catalytic
asymmetric
dearomatization
(CADA)
reactions
is
highly
valuable.
Visible
light-mediated
photocatalysis
demonstrated
to
be
a
powerful
tool
activate
aromatic
compounds
further
synthetic
transformations.
Herein,
dearomative
[2
+
2]
photocycloaddition/ring-expansion
sequence
of
indoles
with
simple
alkenes
was
reported,
providing
facile
access
enantioenriched
cyclopenta[
ACS Catalysis,
Год журнала:
2024,
Номер
14(16), С. 12031 - 12041
Опубликована: Июль 29, 2024
Photocatalytic
enantioselective
Giese
radical
addition
with
inert
C(sp3)–H
bonds
represents
a
highly
efficient
and
economically
favorable
approach
to
synthesizing
diverse
value-added
chiral
molecules
from
abundant
feedstock.
Herein,
we
disclose
quinone-initiated
photocatalytic
asymmetric
of
α-substituted
acrylamides
by
applying
simple
quinones
as
HAT
photocatalysts
in
combination
N,N′-dioxide/praseodymium(III)
catalyst.
A
wide
array
ethers,
thioethers,
selenide,
amines,
alkanes
can
smoothly
transform
into
the
corresponding
α-aryl
amide
derivatives
satisfactory
enantioselectivities
(68
examples,
up
95%
ee)
under
mild
conditions.
Based
on
spectroscopy
studies
control
experiments,
catalytic
cycle
was
proposed,
DFT
calculations
revealed
that
interaction
between
quinone
Lewis
acid
essential
for
enantio-induction
back
hydrogen
atom
transfer
process.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
63(1)
Опубликована: Ноя. 21, 2023
The
direct
α-alkylation
of
acyclic
carbonyls
with
nonactivated
hydrocarbons
through
C(sp3
)-H
functionalization
is
both
extremely
promising
and
notably
challenging,
especially
when
attempting
to
achieve
enantioselectivity
using
iron-based
catalysts.
We
have
identified
a
robust
chiral
iron
complex
for
the
oxidative
cross-coupling
2-acylimidazoles
benzylic
allylic
hydrocarbons,
as
well
alkanes.
readily
available
tunable
N,N'-dioxide
catalysts
in
connection
oxidants
exhibit
precise
asymmetric
induction
(up
99
%
ee)
good
compatibility
moderate
yields
88
yield).
This
protocol
provides
an
elegant
straightforward
access
optically
active
carbonyl
derivatives
starting
from
simple
alkanes
without
prefunctionalization.
Density
functional
theory
(DFT)
calculations
control
experiments
were
made
gain
insight
into
nature
C-C
bond
formation
origin
enantioselectivity.
propose
radical-radical
process
enabled
by
immediate
interconversion
between
ferric
species
ferrous
species.
Chemical Science,
Год журнала:
2024,
Номер
15(39), С. 16050 - 16058
Опубликована: Янв. 1, 2024
We
have
synthesized
β-diaryl-β-hydroxyl-α-amino
acid
derivatives
through
radical
addition-type
aldol
reaction,
which
was
confirmed
by
spectroscopic
experiments,
control
and
DFT
calculations.
Abstract
Over
the
past
decades,
visible
light‐mediated
photocatalysis
has
found
a
mainstream
of
applications
in
synthetic
chemistry.
Organosilanes
have
been
proven
to
be
useful
class
electron
donors
generate
highly
active
radical
species
via
photoinduced
single
transfer
oxidation/fragmentation
sequence,
which
may
undergo
follow‐up
coupling
or
addition
process.
This
minireview
highlights
comprehensive
advances
organosilanes
photoredox
catalyzed
asymmetric
organic
synthesis,
with
particular
emphasis
placed
on
reaction
mechanisms.
We
hope
that
this
review
will
inspire
further
design
and
development
new
reactions
such
readily
accessible
reagents.
The
first
enantioconvergent
transition-metal-catalyzed
amination
of
racemic
α-tertiary
1,2-diols
providing
access
to
vicinal
β-amino
alcohols
is
disclosed.
iridium-catalyzed
reaction
proceeds
through
a
chiral
phosphoric
acid-mediated
borrowing
hydrogen
pathway
with
excellent
yields
and
enantioselectivities
for
range
amine
nucleophiles
1,2-diols.
An
array
were
obtained
high
(50
examples
up
91%
yield
99%
ee).
These
important
amino
alcohol
products
can
be
easily
converted
into
ligands
bioactive
skeletons.
Mechanistic
investigations
proposed
dynamic
kinetic
resolution
involving
imine
formation
then
reduction
as
the
enantiodetermining
step.
Organic Letters,
Год журнала:
2024,
Номер
26(23), С. 5037 - 5042
Опубликована: Июнь 5, 2024
An
enantioselective
hydroaminoalkylation
of
azaaryl
ketones
under
a
transition-metal-free
asymmetric
photoredox
catalysis
platform
is
reported.
A
series
valuable
azaarene-functionalized
1,2-amino
alcohols
featuring
attractive
quaternary
carbon
stereocenters
have
been
synthesized
in
high
yields
with
good
to
excellent
enantioselectivities.
The
viability
readily
accessible
N-aryl
glycines
as
reaction
partners
facilitates
the
conjugate
modification
these
products
into
important
derivatives,
thereby
enhancing
synthetic
utility
current
approach.
Nature Communications,
Год журнала:
2024,
Номер
15(1)
Опубликована: Дек. 30, 2024
The
activation
of
C-C
bond
benzocyclobutenones
under
mild
reaction
conditions
remains
a
challenge.
We
herein
report
photoinduced
catalyst-free
regio-specific
C1-C8
cleavage
benzocyclobutenones,
enabling
the
generation
versatile
ortho-quinoid
ketene
methides
for
aza-[4
+
2]-cycloaddition
with
imines,
which
offers
facile
route
to
isoquinolinone
derivatives,
including
seven
family
members
protoberberine
alkaloids,
gusanlung
A,
B,
D,
8-oxotetrahydroplamatine,
tetrahydrothalifendine,
tetrahydropalmatine,
and
xylopinine.
Furthermore,
catalytic
enantioselective
version
this
strategy
is
also
realized
by
merging
synergistic
photocatalysis
chiral
Lewis
acid
catalysis.
Mechanistic
studies
provide
compelling
evidence
rationalize
photoisomerization/cycloaddition
cascade
process.
