Chemistry - A European Journal,
Journal Year:
2022,
Volume and Issue:
29(15)
Published: Dec. 3, 2022
When
mono-radical
ipso-cyclization
of
aryl
sulfonamides
tend
to
undergo
Smiles-type
rearrangement
through
aromatization-driven
C-S
bond
cleavage,
diradical-mediated
cyclization
must
perform
in
a
distinct
reaction
pathway.
It
is
interesting
meanwhile
challenging
tune
the
rate
cleavage
achieve
chemically
divergent
(hetero)
visible-light
induced
energy
transfer
(EnT)
pathway
involving
diradical
species.
Herein
based
on
designed
indole-tethered
(hetero)arylsulfonamides
reported
which
involves
and
controllable
an
inherent
bond.
The
combined
experimental
computational
results
have
revealed
that
these
substrates
can
be
controlled
by
tuning
heteroaryl
moieties:
a)
If
(hetero)aryl
thienyl,
furyl,
phenanthryl,
etc.,
radical
coupling
double
dearomative
diradicals
(DDDR)
precedes
over
afford
cyclobutene
fused
indolines
[2+2]-cycloaddition;
b)
if
phenyl,
naphthyl,
pyridyl,
indolyl
DDDR
favored
biaryl
products.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(44), P. 20207 - 20213
Published: Oct. 27, 2022
Synthesis
of
bicyclic
scaffolds
has
attracted
growing
interest
because
they
are
high
importance
in
modern
pharmaceutical
development.
Here
we
report
a
strategy
to
access
polysubstituted
2-oxabicyclo[2.1.1]hexanes
single
operation
from
readily
accessible
benzoylformate
esters
and
bicyclo[1.1.0]butanes
via
visible-light-induced
triplet
energy
transfer
catalysis.
The
process
is
proposed
involve
formal
[2π
+
2σ]
photocycloaddition/backbone
C-H
abstraction/aryl
group
migration
sequence.
A
diverse
range
(hetero)aryl
groups
successfully
underwent
the
backbone
(C2)
position
provide
previously
inaccessible
molecules,
ester
product
can
serve
as
handle
for
downstream
manipulation,
thus
offering
opportunities
rapidly
build
up
molecular
complexity
new
sp3-rich
chemical
space.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(8), P. 5232 - 5241
Published: Feb. 13, 2024
In
pursuit
of
potent
pharmaceutical
candidates
and
to
further
improve
their
chemical
traits,
small
ring
systems
can
serve
as
a
potential
starting
point.
Small
units
have
the
additional
merit
loaded
strain
at
core,
making
them
suitable
reactants
they
capitalize
on
this
intrinsic
driving
force.
With
introduction
cyclobutenone
strained
precursor
ketene,
photocycloaddition
with
another
unit,
bicyclo[1.1.0]butane
(BCB),
enables
reactivity
both
π-units
in
transient
ketene.
This
double
strain-release
driven
[2π+2σ]-photocycloaddition
promotes
synthesis
diverse
heterobicyclo[2.1.1]hexane
units,
pharmaceutically
relevant
bioisostere.
The
effective
under
catalyst-free
conditions
high
functional
group
tolerance
defines
its
synthetic
utility.
Experimental
mechanistic
studies
density
theory
(DFT)
calculations
suggest
that
takes
place
via
triplet
mechanism.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(14), P. 10142 - 10149
Published: March 27, 2024
Saturated
bicyclic
compounds
make
up
a
valuable
class
of
building
blocks
in
the
development
agrochemicals
and
pharmaceuticals.
Here,
we
present
synthesis
borylated
bicyclo[2.1.1]hexanes
via
crossed
[2
+
2]-cycloaddition.
Due
to
presence
C–B
bond,
variety
structures
can
be
easily
prepared
that
are
not
accessible
by
other
methods.
Moreover,
rare
photo-ene
reaction
is
also
disclosed,
allowing
for
diastereoselective
trisubstituted
cyclopentanes.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(38)
Published: June 24, 2022
Recently
the
fruitful
merger
of
organoboron
chemistry
and
photocatalysis
has
come
to
forefront
organic
synthesis,
resulting
in
development
new
technologies
access
complex
(non)borylated
frameworks.
Central
success
this
combination
is
control
boron
hybridisation.
Contingent
on
photoactivation
mode,
as
its
neutral
planar
form
or
tetrahedral
boronate
can
be
used
regulate
reactivity.
This
Minireview
highlights
current
state
art
photocatalytic
processes
utilising
compounds,
paying
particular
attention
role
hybridisation
for
target
transformation.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(39), P. 21576 - 21586
Published: Sept. 20, 2023
Alkenylboronates
are
versatile
building
blocks
for
stereocontrolled
synthesis
owing
to
the
traceless
nature
of
boron
group
that
can
be
leveraged
achieve
highly
selective
geometric
isomerization.
Using
thioxanthone
as
an
inexpensive
photocatalyst,
photoisomerization
these
species
continues
provide
expansive
platform
stereodivergent
synthesis,
particularly
in
construction
bioactive
polyenes.
Although
mechanistic
investigations
consistent
with
light-driven
energy
transfer,
direct
experimental
evidence
remains
conspicuously
absent.
Herein,
we
report
a
rigorous
investigation
using
two
widely
used
alkenylboronates
alongside
relevant
reference
compounds.
Through
combination
irradiation
experiments,
transient
absorption
spectroscopic
studies,
kinetic
modeling,
and
DFT
calculations
all
isomers
model
compounds,
it
has
been
possible
unequivocally
detect
characterize
perpendicular
triplet
generated
by
transfer.
Our
results
serve
not
only
blueprint
studies
challenging
organic
sensitizers,
but
guidelines
delineated
have
also
enabled
development
more
sustainable
reaction
conditions:
first
time,
efficient
organocatalytic
isomerization
under
sunlight
become
feasible.
ACS Catalysis,
Journal Year:
2023,
Volume and Issue:
13(14), P. 9806 - 9816
Published: July 11, 2023
Cyclopropanes
bearing
contiguous
all-carbon
quaternary
centers
continue
to
attract
attention
due
their
bioactivities.
However,
methods
obtain
cyclopropanes
with
remain
largely
unexplored
the
high
steric
hindrance
of
these
compounds.
Herein,
we
report
a
visible-light-mediated
energy-transfer
(EnT)
strategy
realize
in
situ
donor/donor
carbenes
from
readily
available
N-tosylhydrazones,
facilitating
synthesis
highly
congested
EWG-free
cyclopropanes.
Through
this
approach,
are
rapidly
installed
into
complex
bioactive
molecules,
fluorescent
and
other
useful
building
blocks
that
challenging
synthesize.
Detailed
mechanistic
reactions
DFT
studies
clearly
demonstrated
role
photosensitizer,
formation
carbenes,
necessity
light
base
system.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(25)
Published: April 11, 2024
Abstract
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
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
(HAT).
Mechanistic
deuterium‐labeling
studies
have
provided
insight
into
outcome
process.
addition,
cyclobutanes
then
demonstrated
useful
selective
oxidation
processes
resulting
cyclobutanones
γ‐lactones.
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 17, 2025
Rigid
bicyclic
hydrocarbons
have
emerged
as
important
building
blocks
in
the
drug
discovery
industry.
Despite
progress
this
general
area,
bicyclo[2.1.0]pentanes
(housanes)
are
an
understudied
class
of
molecules.
Herein
we
report
unconventional
synthesis
borylated
housanes.
Our
method
features
a
broad
scope
and
high
diastereoselectivities
versatile
intermediates.
The
route
involves
strain-release
diboration
bicyclo[1.1.0]butane
intramolecular
deborylative
alkylation.
versatility
bridgehead
boronic
ester
was
demonstrated
several
functionalizations.
Lastly,
mechanism
reaction
investigated,
unusual
stereospecific
diastereoselective
ring
expansion
uncovered.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(41), P. 18790 - 18796
Published: Oct. 6, 2022
A
strategy
for
the
photosensitized
cycloaddition
of
alkenylboronates
and
allylic
alcohols
by
a
temporary
coordination
is
presented.
The
process
allows
synthesis
diverse
range
cyclobutylboronates.
Key
to
development
these
reactions
alcohol
Bpin
unit.
This
not
only
reaction
proceed
in
an
intramolecular
manner
but
also
high
levels
stereo
regiocontrol.
key
aspect
studies
utility
cycloadducts
complex
natural
products
artochamin
J
piperarborenine
B.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(20), P. 11402 - 11414
Published: May 15, 2023
Sensitized
triplet–triplet
annihilation
upconversion
is
a
promising
strategy
to
use
visible
light
for
chemical
reactions
requiring
the
energy
input
of
UV
photons.
This
avoids
unsafe
ultraviolet
sources
and
can
mitigate
photo-damage
provide
access
reactions,
which
filter
effects
hamper
direct
excitation.
Here,
we
report
new
approach
make
blue-to-UV
more
amenable
photochemical
applications.
The
tethering
naphthalene
unit
cyclometalated
iridium(III)
complex
yields
bichromophore
with
high
triplet
(2.68
eV)
naphthalene-based
reservoir
featuring
lifetime
72.1
μs,
roughly
factor
20
longer
than
photoactive
excited
state
parent
complex.
In
combination
three
different
annihilators,
consistently
lower
thresholds
crossover
from
quadratic
into
linear
excitation
power
dependence
regime
were
observed
compared
system
composed
2,5-diphenyloxazole
annihilator
sufficiently
robust
under
long-term
blue
irradiation
continuously
high-energy
singlet-excited
that
drive
normally
light.
Both
photoredox
transfer
catalyses
feasible
using
this
concept,
including
reductive
N–O
bond
cleavage
Weinreb
amides,
C–C
coupling
reaction
based
on
aryl
debromination,
two
Paternò–Büchi
[2
+
2]
cycloaddition
reactions.
Our
work
seems
relevant
in
context
developing
strategies
driving
energetically
demanding
photochemistry
low-energy