ChemCatChem,
Journal Year:
2023,
Volume and Issue:
15(21)
Published: Aug. 16, 2023
Abstract
Visible
light‐induced
photocatalysis
has
been
widely
investigated,
which
offers
exciting
opportunities
to
build
new
catalytic
platforms
that
are
unattainable
under
ground
state
conditions.
Asymmetric
a
longstanding
challenge
due
the
high
reactivity
of
photogenerated
intermediates
leading
strong
background
reaction.
Carbonyl
group
is
an
important
fundamental
scaffold
in
organic
synthesis.
The
photocatalytic
asymmetric
transformations
carbonyl
compounds
for
synthesizing
enantioenriched
secondary
and
tertiary
alcohols
significant
value
but
remain
problematic.
Even
so,
series
intriguing
works
concerning
this
topic
have
reported
recent
year.
This
review
summarizes
advances
area,
mainly
dividing
into
single
synergetic
catalyst
systems,
mechanism
each
reaction
discussed.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(19), P. 8870 - 8882
Published: May 9, 2022
In
contrast
to
the
extensive
but
non-recyclable
use
of
tetraalkoxydiboron(4)
compounds
as
stoichiometric
reagents
in
diverse
reactions,
this
article
reports
an
atom-economical
reaction
using
a
commercial
diboron(4)
catalyst.
The
key
success
was
designing
catalytic
cycle
for
radical
[3
+
2]
cycloaddition
involving
pyridine
cocatalyst
generate
from
catalyst
and
reversibly
mediate
transfer
boronyl
radicals.
comparison
with
known
transition
metal-based
catalysts,
current
features
not
only
metal-free
conditions,
inexpensive
stable
simple
operation
also
remarkably
broadened
substrate
scope.
particular,
previously
unusable
cyclopropyl
ketones
without
activating
group
and/or
alkenes
1,2-disubstitution
1,1,2-trisubstitution
patterns
were
successfully
used
first
time.
Consequently,
challenging
cyclopentane
various
levels
substitution
(65
examples,
57
new
products,
up
six
substituents
at
all
five
ring
atoms)
readily
prepared
generally
high
excellent
yield
diastereoselectivity.
applied
concise
formal
synthesis
anti-obesity
drug
building
natural
product-like
complex
bridged
or
spirocyclic
compounds.
Mechanistic
experiments
computational
investigation
support
proposed
relay
catalysis
featuring
pyridine-assisted
Overall,
work
demonstrates
approach
catalysts
may
lead
development
new,
green,
efficient
metal-like
boron-catalyzed
organic
reactions.
Nature Communications,
Journal Year:
2022,
Volume and Issue:
13(1)
Published: July 6, 2022
Abstract
Unsymmetrical
disulfides
are
widely
found
in
the
areas
of
food
chemistry,
pharmaceutical
industry,
chemical
biology
and
polymer
science.
Due
importance
such
various
fields,
general
methods
for
nondirected
intermolecular
disulfuration
C-H
bonds
highly
desirable.
In
this
work,
conversion
aliphatic
C(sp
3
)-H
aldehydic
2
into
corresponding
C-SS
with
tetrasulfides
(RSSSSR)
as
radical
reagents
is
reported.
The
decatungstate
anion
([W
10
O
32
]
4−
)
photocatalyst
used
C-radical
generation
via
hydrogen
atom
transfer
combination
cheap
sodium
persulfate
(Na
S
8
oxidant.
Herein
a
series
valuable
acyl
alkyl
disulfides,
important
precursors
RSS-anions,
unsymmetrical
dialkyl
synthesized
using
direct
approach.
To
demonstrate
potential
method
late-stage
functionalization,
approved
drugs
natural
products
were
successfully
functionalized.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(48), P. 22140 - 22149
Published: Nov. 22, 2022
Photocatalysis
opens
up
a
new
window
for
carbonyl
chemistry.
Despite
multitude
of
photochemical
reactions
compounds,
visible
light-induced
catalytic
asymmetric
transformations
remain
elusive
and
pose
formidable
challenge.
Accordingly,
the
development
simple,
efficient,
economic
systems
is
ideal
pursuit
chemists.
Herein,
we
report
an
enantioselective
radical
photoaddition
to
ketones
through
Lewis
acid-enabled
photoredox
catalysis
wherein
in
situ
formed
chiral
N,N'-dioxide/Sc(III)-ketone
complex
serves
as
temporary
photocatalyst
trigger
single-electron
transfer
oxidation
silanes
generation
nucleophilic
species,
including
primary,
secondary,
tertiary
alkyl
radicals,
giving
various
enantioenriched
aza-heterocycle-based
alcohols
good
excellent
yields
enantioselectivities.
The
results
electron
paramagnetic
resonance
(EPR)
high-resolution
mass
spectrum
(HRMS)
measurements
provided
favorable
evidence
stereocontrolled
addition
process
involved
this
reaction.
Chemical Science,
Journal Year:
2022,
Volume and Issue:
13(20), P. 5973 - 5981
Published: Jan. 1, 2022
The
pinacol
coupling
reaction,
a
reductive
of
carbonyl
compounds
that
proceeds
through
the
formation
ketyl
radicals
in
presence
an
electron
donor,
affords
corresponding
1,2-diols
one
single
step.
photoredox
version
this
transformation
has
been
accomplished
using
different
organic
dyes
or
photoactive
metal
complexes
sacrificial
donors
such
as
tertiary
amines
Hantzsch's
ester.
Normally,
homo-coupling
reactive
is
neither
diastereo-
nor
enantio-selective.
Herein,
we
report
highly
diastereoselective
reaction
aromatic
aldehydes
promoted
by
5
mol%
non-toxic,
inexpensive
and
available
Cp2TiCl2
complex.
key
feature
allows
complete
control
diastereoselectivity
employment
red-absorbing
dye
redox-active
titanium
Taking
advantage
well-tailored
potential
dye,
selective
reduction
Ti(iv)
to
Ti(iii)
achieved.
These
conditions
enable
d,l
(syn)
diastereoisomer
favored
product
(d.r.
>
20
:
1
most
cases).
Moreover,
employing
simply
prepared
chiral
SalenTi
complex,
new
gave
diastereoselection
for
diastereoisomer,
high
enantiocontrol
(up
92%
enantiomeric
excess).
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(37), P. 20169 - 20175
Published: Sept. 7, 2023
Herein,
we
report
a
new
class
of
electrophotocatalysts,
polycyclic
aromatic
hydrocarbons,
that
promote
the
reduction
unactivated
carbonyl
compounds
to
generate
versatile
ketyl
radical
intermediates.
This
catalytic
platform
enables
previously
challenging
intermolecular
coupling
reactions,
including
those
classic
reductants
(e.g.,
SmI2/HMPA)
have
failed
promote.
More
broadly,
this
study
outlines
an
approach
fundamentally
expand
array
reactive
intermediates
can
be
generated
via
electrophotocatalysis
by
obviating
need
for
rapid
mesolytic
cleavage
following
substrate
reduction.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(32), P. 22829 - 22839
Published: Aug. 1, 2024
The
molecular
editing
of
ketones
represents
an
appealing
strategy
due
to
its
ability
maximize
the
structural
diversity
ketone
compounds
in
a
straightforward
manner.
However,
developing
efficient
methods
for
arbitrary
modification
ketonic
molecules,
particularly
those
integrated
within
complex
skeletons,
remains
significant
challenge.
Herein,
we
present
unique
recasting
that
involves
radical
acylation
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(4), P. 2463 - 2471
Published: Feb. 3, 2022
A
simple
procedure
is
reported
for
the
nickel-catalyzed
defluorinative
alkylation
of
unactivated
aliphatic
aldehydes.
The
process
involves
catalytic
reductive
union
trifluoromethyl
alkenes
with
aldehydes
using
a
nickel
complex
6,6'-disubstituted
bipyridine
ligand
zinc
metal
as
terminal
reductant.
protocol
distinguished
by
its
broad
substrate
scope,
mild
conditions,
and
setup.
Reaction
outcomes
are
consistent
intermediacy
an
α-silyloxy(alkyl)nickel
intermediate
generated
low-valent
catalyst,
silyl
electrophile,
aldehyde
substrate.
Mechanistic
findings
cyclopropanecarboxaldehyde
provide
insights
into
nature
reactive
intermediates
illustrate
fundamental
reactivity
differences
that
governed
subtle
changes
in
structure.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(34)
Published: July 11, 2022
Herein,
we
report
a
reductive
cross-coupling
reaction
of
α-oxy
halides,
simply
generated
from
aldehydes,
with
series
C(sp2
)-
and
C(sp)-electrophiles.
A
wide
range
aryl
heteroatom
vinyl
bromides,
alkynyl
acyl
chlorides
react
unhindered
hindered
aldehyde-derived
halides
by
providing
protected
alcohols
as
well
α-hydroxy
ketones.
Noteworthy,
the
couplings
are
achieved
not
only
through
thermal
catalysis
use
metal
reductants
but
also
photocatalysis,
electrochemistry,
mechanochemistry.
The
unrestricted
interchange
four
strategies
indicates
their
underlying
mechanistic
similarities.
generation
NiI
intermediate
is
proposed
to
be
key
point
for
ketyl
radical
formation
via
single-electron
transfer
(SET)
event,
which
was
rationalized
an
array
control
experiments
density
functional
theory
(DFT)
calculations.