The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(12), С. 8836 - 8844
Опубликована: Июнь 5, 2024
The
photocatalytic
synthesis
of
thermodynamically
less-stable
Z-alkenes
has
received
considerable
research
attention
in
recent
years.
In
this
study,
a
recycling
photoreactor
was
applied
to
the
photoisomerization
E-alkenes
(cinnamamide
and
Weinreb
amide
derivatives)
produce
Z-alkenes.
closed-loop
system
comprises
an
immobilized
photosensitizer
achieve
rapid
high-performance
liquid
chromatography
instrument
for
separation
Z/E
diastereomers.
After
4–10
cycles,
desired
pure
were
obtained
efficiently.
system,
(thioxanthone)
covalently
on
silica
gel
via
bonding,
which
led
enhanced
activity
compared
parent
thioxanthone.
This
shows
promise
as
alternative
production
Herein,
we
report
the
use
of
isonitriles
as
alkyl
radical
precursors
in
light-mediated
hydro-
and
deuterodeamination
reactions.
The
reaction
is
scalable,
shows
broad
functional
group
compatibility
potential
to
be
used
late-stage
functionalization.
Importantly,
method
general
for
Cα-1º,
Cα-2º
Cα-3º
isonitriles.
For
most
examples,
high
yields
were
obtained
through
direct
visible-light
irradiation
isonitrile
presence
a
silyl
precursor.
Interestingly,
an
organic
photocatalyst
(4CzIPN)
dramatic
acceleration
was
observed.
In
depth
mechanistic
studies
using
UV-vis
absorption,
steady-state
time-resolved
photoluminescence,
transient
absorption
spectroscopy
suggest
that
excited
state
4CzIPN
able
sensitize
single
electron
transfer.
While
polyborylated
alkenes
are
being
recognized
for
their
elevated
status
as
highly
valuable
reagents
in
modern
organic
synthesis,
allowing
efficient
access
to
a
diverse
array
of
transformations,
including
the
formation
C–C
and
C–heteroatom
bonds,
potential
energy-transfer
reactive
groups
has
remained
unexplored.
Yet,
this
holds
key
generating
elusive
biradical
species,
which
can
be
captured
by
radophile
olefins,
thereby
leading
construction
new
highly-borylated
scaffolds.
Herein,
we
report
designed
strategy
photosensitized
[2+2]-cycloadditions
poly-borylated
with
various
olefins
enabling
regioselective
synthesis
cyclobutane
motifs,
1,1-di-,
1,1,2-tri-,
1,1,2,2-tetra-borylated
cyclobutanes.
In
fact,
these
compounds
belong
family
that
presently
lacks
synthetic
pathways.
Interestingly,
when
α-methylstyrene
was
used,
reaction
involves
an
interesting
1,5-hydrogen
atom
transfer.
Mechanistic
deuterium-labeling
studies
have
provided
insight
into
outcome
transfer
process.
addition,
cyclobutanes
then
demonstrated
useful
selective
oxidation
processes
resulting
cyclobutanones
γ-lactones.
Beilstein Journal of Organic Chemistry,
Год журнала:
2024,
Номер
20, С. 1236 - 1245
Опубликована: Май 28, 2024
Organic
photocatalysts
frequently
possess
dual
singlet
and
triplet
photoreactivity
a
thorough
photochemical
characterization
is
essential
for
efficient
light-driven
applications.
In
this
article,
the
mode
of
action
polyazahelicene
catalyst
(Aza-H)
was
investigated
using
laser
flash
photolysis
(LFP).
The
study
revealed
that
chromophore
can
function
as
singlet-state
photoredox
in
sulfonylation/arylation
styrenes
sensitizer
energy
transfer
catalysis.
lifetime
sufficiently
long
to
exploit
exceptional
excited
state
reduction
potential
activation
4-cyanopyridine.
Photoinduced
electron
generating
radical
cation
directly
observed
confirming
previously
proposed
mechanism
three-component
reaction.
Several
steps
cycle
were
separately,
providing
deep
insights
into
complex
mechanism.
triplet-excited
Aza-H,
which
studied
with
quantitative
LFP,
formed
quantum
yield
0.34.
pronounced
formation
exploited
isomerization
reaction
(
E
)-stilbene
Z
-isomer
cyclization
cinnamyl
chloride.
Catalyst
degradation
mainly
occurs
through
long-lived
Aza-H
(28
µs),
but
photostability
greatly
increased
when
efficiently
reacts
catalytic
such
turnover
numbers
exceeding
4400
are
achievable
organocatalyst.
Organic Letters,
Год журнала:
2024,
Номер
26(23), С. 4916 - 4920
Опубликована: Май 31, 2024
The
present
Letter
demonstrates
a
photoswitched
stereodivergent
synthesis
of
allylic
sulfones
from
sodium
sulfinates,
triphenylvinylphosphonium
chloride,
and
(hetero)aromatic
aldehydes
in
single
step.
Mechanistically,
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(12), С. 8836 - 8844
Опубликована: Июнь 5, 2024
The
photocatalytic
synthesis
of
thermodynamically
less-stable
Z-alkenes
has
received
considerable
research
attention
in
recent
years.
In
this
study,
a
recycling
photoreactor
was
applied
to
the
photoisomerization
E-alkenes
(cinnamamide
and
Weinreb
amide
derivatives)
produce
Z-alkenes.
closed-loop
system
comprises
an
immobilized
photosensitizer
achieve
rapid
high-performance
liquid
chromatography
instrument
for
separation
Z/E
diastereomers.
After
4–10
cycles,
desired
pure
were
obtained
efficiently.
system,
(thioxanthone)
covalently
on
silica
gel
via
bonding,
which
led
enhanced
activity
compared
parent
thioxanthone.
This
shows
promise
as
alternative
production
