Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
62(7)
Опубликована: Дек. 21, 2022
Cyclobutenones
provide
a
straightforward
four-carbon
ring
platform
for
further
structural
elaborations
in
that
every
carbon
atom
of
the
could
be
potentially
functionalized.
We
report
here
nickel
catalyzed
enantioconvergent
Negishi
coupling
4-iodocyclobutenones
with
an
array
aryl
or
alkenyl
zinc
reagents
to
access
enantioenriched
4-substituted
cyclobutenones,
from
which
modular
approach
synthesis
1,2,3,4-tetrasubstituted
cyclobutanes
was
demonstrated.
Chemical Reviews,
Год журнала:
2021,
Номер
122(2), С. 1654 - 1716
Опубликована: Окт. 4, 2021
Asymmetric
catalysis
is
a
major
theme
of
research
in
contemporary
synthetic
organic
chemistry.
The
discovery
general
strategies
for
highly
enantioselective
photochemical
reactions,
however,
has
been
relatively
recent
development,
and
the
variety
photoreactions
that
can
be
conducted
stereocontrolled
manner
consequently
somewhat
limited.
photocatalysis
complicated
by
short
lifetimes
high
reactivities
characteristic
photogenerated
reactive
intermediates;
design
catalyst
architectures
provide
effective
enantiodifferentiating
environments
these
intermediates
while
minimizing
participation
uncontrolled
racemic
background
processes
proven
to
key
challenge
progress
this
field.
This
review
provides
summary
chiral
structures
have
studied
solution-phase
asymmetric
photochemistry,
including
sensitizers,
inorganic
chromophores,
soluble
macromolecules.
While
some
photocatalysts
are
derived
from
privileged
both
ground-state
transformations,
others
structural
designs
unique
offer
insight
into
logic
required
photocatalysis.
Chemical Society Reviews,
Год журнала:
2024,
Номер
53(3), С. 1068 - 1089
Опубликована: Янв. 1, 2024
Leveraging
light
energy
to
expose
the
‘dark’
reactive
states
describes
whole
essence
of
triplet–triplet
transfer.
This
offers
an
impressive
opportunity
conduct
a
multitude
diverse
reactions
and
access
sought-after
molecular
motifs.
Abstract
Visible‐light
photocatalysis
has
advanced
as
a
versatile
tool
in
organic
synthesis.
However,
attaining
precise
stereocontrol
photocatalytic
reactions
been
longstanding
challenge
due
to
undesired
photochemical
background
and
the
involvement
of
highly
reactive
radicals
or
radical
ion
intermediates
generated
under
conditions.
To
address
this
problem
expand
synthetic
utility
reactions,
number
innovative
strategies,
including
mono‐
dual‐catalytic
approaches,
have
recently
emerged.
Of
these,
exploiting
chiral
organocatalysis,
such
enamine
catalysis,
iminium‐ion
Brønsted
acid/base
N
‐heterocyclic
carbene
induce
chirality
transfer
widely
explored.
This
Review
aims
provide
current,
comprehensive
overview
asymmetric
enabled
by
organocatalysts
published
through
June
2021.
The
substrate
scope,
advantages,
limitations,
proposed
reaction
mechanisms
each
are
discussed.
review
should
serve
reference
for
development
visible‐light‐induced
promote
improvement
chemical
reactivity
stereoselectivity
these
reactions.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(18)
Опубликована: Фев. 25, 2022
Abstract
The
photochemical
synthesis
of
yet
unknown
2‐oxospiro[azetidine‐3,3′‐indolines]
(17
examples,
80–95
%
yield),
2,4‐dioxospiro[azetidine‐3,3′‐indolines]
(eight
87–97
and
1‐oxo‐1,3‐dihydrospiro[indene‐2,3′‐indolines]
85–97
yield)
is
described.
Starting
from
readily
accessible
3‐substituted
indoles,
a
dearomatization
the
indole
core
was
accomplished
upon
irradiation
at
λ=420
nm
in
presence
thioxanthen‐9‐one
(10
mol%)
as
sensitizer.
Based
on
mechanistic
evidence
(triplet
energy
determination,
deuteration
experiments,
by‐product
analysis)
it
proposed
that
reaction
proceeds
by
transfer
via
1,4‐
or
1,5‐diradical
intermediate.
latter
intermediates
are
formed
excited
state
hydrogen
atom
suitable
alkyl
groups
within
C3
substituent
to
C2
carbon
atom.
Subsequent
ring
closure
with
pronounced
diastereoselectivity
generate
4‐
5‐membered
spirocyclic
dearomatized
product
several
options
for
further
functionalization.
Nature Communications,
Год журнала:
2022,
Номер
13(1)
Опубликована: Май 23, 2022
Solid-state
photochemical
reactions
of
olefinic
compounds
have
been
demonstrated
to
represent
powerful
access
organic
cyclic
molecules
with
specific
configurations.
However,
the
precise
control
stereochemistry
in
these
remains
challenging
owing
complex
and
fleeting
configuration
transformations.
Herein,
we
report
a
unique
approach
regiospecific
configurations
C
=
groups
intermediates
by
varying
temperatures
multiple-step
thermal/photoinduced
reactions,
thus
successfully
realizing
reversible
ring
closing/opening
changes
using
single-crystal
coordination
polymer
platform.
All
stereochemical
transitions
are
observed
situ
X-ray
diffraction,
powder
diffraction
infrared
spectroscopy.
Density
functional
theory
calculations
allow
us
rationalize
mechanism
synergistic
This
can
be
generalized
analysis
possible
transformations
unravel
detailed
for
any
inorganic,
macromolecular
susceptible
incorporation
into
platforms.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(43), С. 23771 - 23780
Опубликована: Окт. 18, 2023
Given
the
importance
of
cyclic
frameworks
in
molecular
scaffolds
and
drug
discovery,
it
is
intriguing
to
precisely
forge
manipulate
ring
systems
synthetic
chemistry.
In
this
field,
intermolecular
synthesis
densely
substituted
cyclobutanes
with
precise
diastereocontrol
under
simple
reaction
conditions
remains
a
challenge.
Herein,
photoredox
strategy
for
difunctionalization
bicyclo[1.1.0]butanes
(BCBs)
high
regio-
syn-selectivity
disclosed.
C-S
σ-bond
cleavage
partially
unsaturated
sulfur-containing
bifunctional
reagents
an
overall
strain-release-driven
process
enables
thio-alkynylation,
-alkenylation,
-allylation
BCBs
mild
demonstrates
generality
protocol.
Mechanistic
studies
suggest
that
intermediacy
distonic
radical
cations
might
be
key
efficient
scission
σ-bonds
origin
diastereoselectivity.
Organic & Biomolecular Chemistry,
Год журнала:
2023,
Номер
21(17), С. 3477 - 3502
Опубликована: Янв. 1, 2023
This
review
article
presents
an
in-depth
analysis
of
the
strategies
and
methodologies
for
using
chiral
phosphoric
acids
as
organocatalysts
in
asymmetric
syntheses
from
recent
literature.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(28), С. 15054 - 15060
Опубликована: Июль 5, 2023
Radical
cations
show
a
unique
reactivity
that
is
fundamentally
different
from
of
conventional
and
have
thus
attracted
considerable
attention
as
alternative
cationic
intermediates
for
novel
types
organic
reactions.
However,
asymmetric
catalysis
to
promote
enantioselective
radical
cation
reactions
remains
major
challenge
in
contemporary
synthesis.
Here,
we
report
the
judicious
design
an
ion
pair
consisting
chiral
counteranion
induces
excellent
level
enantioselectivity.
This
strategy
was
applied
enantio-,
diastereo-,
regioselective
[2
+
2]
cycloadditions,
well
[4
by
using
iron(III)
photoredox
catalysis.
We
anticipate
this
has
potential
expand
use
several
mature
anions
develop
numerous
unprecedented
ACS Catalysis,
Год журнала:
2024,
Номер
14(10), С. 7321 - 7331
Опубликована: Апрель 25, 2024
In
the
recently
burgeoning
field
of
asymmetric
[2
+
2]
photocycloaddition,
a
challenging
hurdle
lies
in
achieving
multilevel
control
chemo-,
regio-,
diastereo-,
and
enantioselectivities
cross-coupling
photoreactions,
which
often
result
chaotic
outcomes
when
partners
show
similar
electronic
optical
properties.
Here,
we
introduce
biomimetic
cage-pocket
confined
photocatalytic
protocol
that
can
effectively
realize
bimolecular
recognition
manipulate
excited
triplet-state
dynamics
through
stereochemical
confinement.
This
approach
allows
for
highly
selective
synthesis
heterocoupled
syn-HH
(head-to-head)
enantiomers
from
two
photoactive
α,β-unsaturated
carbonyl
compounds,
are
typically
difficult
to
access
via
conventional
strategies
due
competitive
pathways.
We
find
cooperative
heteromolecular
binding
plays
critical
role
initial
chemoselective
successive
stereoselective
photoreactions.
Notably,
open
pockets
cage
reactor
display
tolerable
guest–host
match
but
products–host
mismatch
wide
scope
substrates,
overcoming
common
limitations
associated
with
enzyme-mimicking
reactors
such
as
guest
specificity
product
inhibition
against
catalytic
generality
turnover.