Angewandte Chemie,
Journal Year:
2024,
Volume and Issue:
136(47)
Published: Aug. 10, 2024
Abstract
The
functionalization
of
pyridines
is
crucial
for
the
rapid
construction
and
derivatization
agrochemicals,
pharmaceuticals,
materials.
Conventional
approaches
have
primarily
focused
on
ortho
‐
para
‐positions,
while
achieving
precise
meta‐selective
functionalization,
particularly
at
C5
position
in
substituted
pyridines,
remains
a
formidable
challenge
due
to
intrinsic
electronic
properties
pyridines.
Herein,
we
present
new
strategy
meta
C5‐selective
C−H
sulfonylation
N
‐amidopyridinium
salts,
which
employs
transient
enamine‐type
intermediate
generated
through
nucleophilic
addition
salts.
This
process
harnesses
power
electron
donor‐acceptor
complexes,
enabling
high
selectivity
broad
applicability,
including
complex
bearing
valuable
sulfonyl
functionalities
under
mild
conditions
without
need
an
external
photocatalyst.
remarkable
selectivity,
combined
with
applicability
late‐stage
significantly
expands
toolbox
pyridine
unlocking
access
previously
unattainable
‐sulfonylated
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(15), P. 10899 - 10907
Published: April 3, 2024
In
the
long-standing
quest
to
synthesize
fundamental
building
blocks
with
key
functional
group
motifs,
photochemistry
in
recent
past
has
comprehensively
established
its
attractiveness.
Amino
alcohols
are
not
only
functionally
diverse
but
ubiquitous
biologically
active
realm
of
compounds.
We
developed
bench-stable
bifunctional
reagents
that
could
then
access
sparsely
reported
γ-amino
directly
from
feedstock
alkenes
through
energy
transfer
(EnT)
photocatalysis.
A
designed
1,3-linkage
across
is
made
possible
by
intervention
a
radical
Brook
rearrangement
takes
place
downstream
EnT-mediated
homolysis
our
reagent(s).
combination
experimental
mechanistic
investigations
and
detailed
computational
studies
(DFT)
indicates
chain
propagated
reaction
pathway.
ACS Catalysis,
Journal Year:
2025,
Volume and Issue:
15(3), P. 1854 - 1941
Published: Jan. 17, 2025
Over
the
past
decade,
visible-light-mediated
energy-transfer
(EnT)
catalysis,
particularly
triplet–triplet
(TTEnT)
has
emerged
as
a
mild
and
environmentally
friendly
approach
for
diverse
organic
synthetic
transformations.
In
contrast
to
photoredox
which
typically
requires
sacrificial
electron
donors
or
acceptors
complete
catalytic
cycle,
EnT
photocatalysis
generally
proceeds
with
high
atom
economy
while
minimizing
generation
of
wasteful
byproducts.
Furthermore,
successful
catalysis
is
contingent
upon
precise
control
redox
potentials
both
photocatalysts
substrates,
strategies
are
primarily
influenced
by
triplet
energy
compatibility
between
these
entities.
Considering
growing
importance
photocatalysis,
well
hydrofunctionalization
difunctionalization
reactions
in
synthesis,
this
review
systematically
summarizes
significant
advancements
EnT-enabled
unsaturated
compounds
via
sigma-bond
homolysis
over
decade.
Special
emphasis
placed
on
elucidating
substrate
scopes
mechanistic
scenarios.
Additionally,
discusses
versatile
applications
methodologies
addresses
current
challenges
opportunities
within
evolving
research
field.
This
structured
into
six
main
categories
based
different
types
sigma-bonds
undergoing
homolysis.
These
include
transformations
mediated
1)
N–O
bond
oxime
esters
other
N,O-radical
precursors;
2)
N–S
N-sulfonyl
imines
N,S-radical
3)
chalcogen–chalcogen
disulfides
oxy/thio/selenosulfonates;
4)
C–S
tri/difluoromethylated
sulfinates,
acetylenic
triflones,
arylsulfonium
salts;
5)
C–X
(X
=
halogen)
halides;
6)
acceptors.
Through
providing
theoretical
backgrounds
along
comprehensive
overview
currently
employed
acceptors,
photosensitizers,
contemporary
EnT-induced
compounds,
aims
serve
an
invaluable
resource
future
innovations
rapidly
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(10), P. 2108 - 2113
Published: March 5, 2024
A
metal-free
photosensitized
1,2-imino-sulfamoylation
of
olefins
by
employing
a
tailor-made
sulfamoyl
carbamate
as
the
difunctionalization
reagent
has
been
established.
This
protocol
exhibits
versatility
across
broad
substrate
scope,
including
aryl
and
aliphatic
alkenes,
leading
to
synthesis
diverse
β-imino
sulfonamides
in
moderate
good
yields.
method
is
characterized
its
reaction
system,
mild
conditions,
excellent
regioselectivity,
high
atom
economy,
serving
promising
platform
for
preparation
β-amino
sulfonamide-containing
molecules,
particularly
context
drug
discovery.
Advanced Synthesis & Catalysis,
Journal Year:
2024,
Volume and Issue:
366(7), P. 1517 - 1522
Published: Jan. 31, 2024
Abstract
A
photoredox‐catalyzed
three‐component
sulfonaminoformyloxylation
reaction
between
alkenes,
N
‐aminopyridinium
salts
and
DMF
has
been
developed,
which
avoids
the
usage
of
erosive
formic
acid
as
formyloxylation
reagent.
Besides
DMF,
alkyl
aryl
carboxylic
acids
proved
to
be
feasible
nucleophiles
afford
various
β
‐amino
esters.
The
robustness
this
method
was
further
demonstrated
by
its
applicability
in
late‐stage
modification
biological
molecules.
Control
experiments
suggested
that
a
sulfonamidyl
radical
involved
reaction.
Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(38), P. 7009 - 7013
Published: Sept. 14, 2023
The
1,2-iminylalkylation
of
diazenes
using
alkyl
iodides
in
combination
with
an
O-benzoyl
oxime
is
reported.
In
this
transformation,
acted
as
a
radical
precursor
and
XAT
mediator.
addition
to
common
iodides,
other
such
iodomethane,
iodomethane-d3,
trifluoroiodomethane,
ethyl
difluoroiodoacetate,
iodoalkanes
containing
unprotected
hydroxyl
amide
groups
can
also
serve
C-radical
precursors
the
electrophilic
acceptors.
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(17), P. 3661 - 3666
Published: April 24, 2024
Considering
the
ubiquitous
presence
of
pyridine
moieties
in
pharmaceutical
compounds,
it
holds
immense
value
to
develop
practical
and
straightforward
methodologies
for
accessing
heterocyclic
aromatic
hydrocarbons.
In
recent
years,
N-alkoxypyridinium
salts
have
emerged
as
convenient
radical
precursors,
enabling
generation
corresponding
alkoxy
radicals
through
single-electron
transfer.
Herein,
we
present
first
report
on
visible-light-mediated
intermolecular
alkoxypyridylation
alkenes
employing
N-alkoxylpyridinium
bifunctional
reagents
with
an
exceptionally
low
catalyst
loading
(0.5
mol
%).
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: July 19, 2024
Abstract
Visible-light
photocatalysis
has
evolved
as
a
powerful
technique
to
enable
controllable
radical
reactions.
Exploring
unique
photocatalytic
mode
for
obtaining
new
chemoselectivity
and
product
diversity
is
of
great
significance.
Herein,
we
present
photo-induced
chemoselective
1,2-diheteroarylation
unactivated
alkenes
utilizing
halopyridines
quinolines.
The
ring-fused
azaarenes
serve
not
only
substrate,
but
also
potential
precursors
halogen-atom
abstraction
pyridyl
generation
in
this
photocatalysis.
As
complement
metal
catalysis,
process
with
mild
redox
neutral
conditions
assembles
two
different
heteroaryl
groups
into
regioselectively
contribute
broad
substrates
scope.
obtained
products
containing
aza-arene
units
permit
various
further
diversifications,
demonstrating
the
synthetic
utility
protocol.
We
anticipate
that
protocol
will
trigger
advancement
alkyl/aryl
halides
activation.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(47)
Published: Aug. 10, 2024
Abstract
The
functionalization
of
pyridines
is
crucial
for
the
rapid
construction
and
derivatization
agrochemicals,
pharmaceuticals,
materials.
Conventional
approaches
have
primarily
focused
on
ortho
‐
para
‐positions,
while
achieving
precise
meta‐selective
functionalization,
particularly
at
C5
position
in
substituted
pyridines,
remains
a
formidable
challenge
due
to
intrinsic
electronic
properties
pyridines.
Herein,
we
present
new
strategy
meta
C5‐selective
C−H
sulfonylation
N
‐amidopyridinium
salts,
which
employs
transient
enamine‐type
intermediate
generated
through
nucleophilic
addition
salts.
This
process
harnesses
power
electron
donor‐acceptor
complexes,
enabling
high
selectivity
broad
applicability,
including
complex
bearing
valuable
sulfonyl
functionalities
under
mild
conditions
without
need
an
external
photocatalyst.
remarkable
selectivity,
combined
with
applicability
late‐stage
significantly
expands
toolbox
pyridine
unlocking
access
previously
unattainable
‐sulfonylated
