Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(3), P. 533 - 537
Published: Jan. 13, 2023
The
difluoromethyl
group
(CF2H)
is
of
great
importance
in
medicinal
chemistry.
We
report
herein
an
efficient
method
for
the
synthesis
diversified
α-difluoromethyl
amines
through
copper-catalyzed
hydroamination
gem-difluoroalkenes,
where
C-N
bond
formed
via
a
α-CF2H
transition-metal
intermediate.
This
new
reaction
proceeds
Cu-H
insertion
to
gem-difluoroalkenes
and
gives
valuable
alkyl-CF2H-containing
compounds,
which
overcome
much
more
challenged
β-F
elimination
from
α-fluoroalkyl
organocopper
species.
exhibits
broad
substrate
scope
with
readily
available
starting
materials
commercial
catalysis.
Accounts of Chemical Research,
Journal Year:
2022,
Volume and Issue:
56(2), P. 169 - 186
Published: Dec. 26, 2022
ConspectusThe
past
decades
have
witnessed
tremendous
progress
on
radical
reactions.
However,
in
comparison
with
carbon,
nitrogen,
oxygen,
and
other
main
group
element
centered
radicals,
the
synthetic
chemistry
of
boron
radicals
was
less
studied,
mainly
due
to
high
electron-deficiency
instability
such
3-center-5-electron
species.
In
1980s,
Roberts
co-workers
found
that
coordination
a
Lewis
base
(amines
or
phosphines)
center
could
form
4-center-7-electron
boryl
(Lewis
base-boryl
LBRs)
are
be
more
stable.
only
limited
applications
were
developed.
2008,
Curran
achieved
breakthrough
discovery
N-heterocyclic
carbene
(NHC)
which
enable
range
reduction
polymerization
Despite
these
exciting
findings,
powerful
valuable
LBRs
would
expected,
given
structures
reactivities
easily
modulated,
provide
ample
opportunities
discover
new
this
Account,
summary
our
key
contributions
LBR-enabled
borylation
reactions
selective
activation
inert
carbon-heteroatom
bonds
will
presented.Organoboron
compounds
shown
versatile
chemical
society,
their
syntheses
rely
principally
ionic
The
development
mechanistically
different
allows
synthesizing
products
inaccessible
by
traditional
methods.
For
purpose,
we
progressively
developed
series
NHC-boryl
mediated
chemo-,
regio-,
stereoselective
alkenes
alkynes,
wide
variety
structurally
diverse
organoboron
molecules
successfully
prepared.
utility
borylated
also
demonstrated.
Furthermore,
disclosed
photoredox
protocol
for
oxidative
generation
enabled
useful
defluoroborylation
arylboration
reactions.Selective
bond
is
an
ideal
way
convert
simple
starting
materials
value-added
products,
while
cleavage
bonds,
particular
chemoselectivity
control
when
multiple
identical
present
similar
environments,
remains
long-standing
challenge.
We
envisaged
finely
tuning
properties
might
solution
address
Recently,
4-dimethylaminopyridine
(DMAP)-boryl
promoted
sequential
C-F
functionalization
trifluoroacetic
acid
derivatives,
α-C-F
selectively
snipped
via
spin-center
shift
mechanism.
This
strategy
enables
facile
conversion
abundantly
available
highly
mono-
difluorinated
molecules.
Encouraged
finding,
further
three-step
sequence
construct
all-carbon
quaternary
centers
from
trichloromethyl
groups,
where
three
C-Cl
cleaved
rational
choice
suitable
precursors
each
step.
dehydroxylative
alkylation
α-hydroxy
carboxylic
derivatives
achieved,
allowing
efficient
some
biomass
platform
value
products.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(3), P. 1300 - 1310
Published: Jan. 11, 2024
Directly
utilizing
abundant
and
inexpensive
sources
of
aliphatic
carboxylic
acids
is
highly
attractive
for
the
synthesis
CF2H-
CH3-containing
compounds.
Herein,
we
report
a
versatile
photoinduced
iron-catalyzed
platform
hydrodifluoromethylation
hydromethylation
alkenes
without
need
additional
stoichiometric
oxidants.
These
two
transformations
are
accomplished
by
visible-light-induced
ligand-to-iron
charge
transfer
open-shell
activation
system
using
industrial
chemical
difluoroacetic
acetic
as
precursors
postulated
to
operate
via
difluoromethyl
methyl
radical-mediated
decarboxylation
mechanism.
Experimental
results
show
that
strategy
also
applicable
difunctionalization
unactivated
alkenes.
Meanwhile,
this
provides
viable
route
pharmaceutically
active
molecules
containing
deuterated
units.
The
protocol
exhibits
several
features,
including
mild
reaction
conditions,
divergent
radical
precursors,
operational
simplicity
scalability,
good
chemo-
regioselectivity,
scalability
supported
continuous
flow
technology,
ability
provide
high-value
building
blocks
applications
in
one
step.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
145(2), P. 991 - 999
Published: Dec. 30, 2022
Herein,
we
present
a
comprehensive
study
on
the
use
of
N-heterocyclic
carbene
(NHC)-ligated
boryl
radicals
to
enable
C(sp3)–C(sp3)
bond
formation
under
visible-light
irradiation
via
Halogen-Atom
Transfer
(XAT).
The
methodology
relies
an
acridinium
dye
generate
boron-centered
from
corresponding
NHC-ligated
boranes
single-electron
transfer
(SET)
and
deprotonation.
These
subsequently
engage
with
alkyl
halides
in
XAT
step,
delivering
desired
nucleophilic
radicals.
strategy
is
very
mild
accommodates
broad
scope
halides,
including
medicinally
relevant
compounds
biologically
active
molecules.
key
role
operative
reaction
mechanism
has
been
elucidated
through
combination
experimental,
spectroscopic,
computational
studies.
This
stands
as
significant
advancement
chemistry
radicals,
which
had
long
restricted
radical
reductions,
enabling
C–C
photoredox
conditions.
Chemical Society Reviews,
Journal Year:
2023,
Volume and Issue:
52(17), P. 6120 - 6138
Published: Jan. 1, 2023
In
recent
years,
the
activation
of
unactivated
alkyl
chlorides
through
light-induced
processes
has
emerged
as
a
promising
field
in
radical
chemistry,
and
led
to
new
transformations
organic
synthesis.
Direct
utilization
C(sp3)-hybridized
electrophiles
enables
facile
construction
carbon-carbon
carbon-heteroatom
bonds.
Furthermore,
studies
medicinal
chemistry
indicate
that
their
presence
is
associated
with
high
levels
success
clinical
trials.
This
review
summarizes
advances
photoinduced
discusses
mechanistic
aspects
underlying
these
reactions.
We
anticipate
this
will
serve
valuable
resource
for
researchers
chemical
bond
functionalization,
inspire
considerable
developments
drug
synthesis,
materials
science
other
related
disciplines.
Chemical Science,
Journal Year:
2023,
Volume and Issue:
14(12), P. 3229 - 3234
Published: Jan. 1, 2023
Reagents
for
the
activation
of
C–Cl
bond
via
XAT
process
are
described.
The
reaction
efficiency
is
based
on
stereoelectronic
effects.
method
applied
to
chlorofluorocarbons.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(13), P. 7638 - 7647
Published: March 22, 2023
The
efficient
and
selective
functionalization
of
icosahedral
carboranes
(C2B10H12)
at
the
boron
vertexes
is
a
long-standing
challenge
owing
to
presence
10
inert
B-H
bonds
in
similar
chemical
environment.
Herein,
we
report
new
reaction
paradigm
for
direct
via
homolysis
enabled
by
nitrogen-centered
radical-mediated
hydrogen
atom
transfer
(HAT)
strategy.
Both
HAT
process
carborane
bond
resulting
boron-centered
carboranyl
radical
intermediate
have
been
confirmed
experimentally.
occurs
most
electron-rich
vertex
with
lowest
dissociation
energy
(BDE).
Using
this
strategy,
diverse
derivatization,
including
thiolation,
selenation,
alkynylation,
alkenylation,
cyanation,
halogenation,
achieved
satisfactory
yields
under
photoinitiated
condition
metal-free
redox-neutral
fashion.
Moreover,
synthetic
utility
current
protocol
was
also
demonstrated
both
scale-up
construction
carborane-based
functional
molecules.
Therefore,
methodology
opens
pathway
functionalization,
which
distinct
from
heterolytic
mechanism
traditional
strategies.
Molecules,
Journal Year:
2023,
Volume and Issue:
28(16), P. 6127 - 6127
Published: Aug. 18, 2023
The
functionalisation
of
C–H
bonds
has
been
an
enormous
achievement
in
synthetic
methodology,
enabling
new
retrosynthetic
disconnections
and
affording
simple
equivalents
for
synthons.
Hydrogen
atom
transfer
(HAT)
is
a
key
method
forming
alkyl
radicals
from
substrates.
Classic
reactions,
including
the
Barton
nitrite
ester
reaction
Hofmann–Löffler–Freytag
reaction,
among
others,
provided
early
examples
HAT.
However,
recent
developments
photoredox
catalysis
electrochemistry
have
made
HAT
powerful
tool
capable
introducing
wide
range
functional
groups
into
bonds.
Moreover,
greater
mechanistic
insights
stimulated
development
increasingly
site-selective
protocols.
Site-selectivity
can
be
achieved
through
tuning
electron
density
at
certain
using
additives,
judicious
choice
reagent,
solvent
system.
Herein,
we
describe
latest
methods
functionalizing
C–H/Si–H/Ge–H
indirect
between
2018–2023,
as
well
critical
discussion
reagents,
aspects,
substrate
scopes,
background
contexts
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(11), P. 7191 - 7197
Published: March 5, 2024
Photoenzymatic
intermolecular
hydroalkylations
of
olefins
are
highly
enantioselective
for
chiral
centers
formed
during
radical
termination
but
poorly
selective
set
in
the
C–C
bond-forming
event.
Here,
we
report
evolution
a
flavin-dependent
"ene"-reductase
to
catalyze
coupling
α,α-dichloroamides
with
alkenes
afford
α-chloroamides
good
yield
excellent
chemo-
and
stereoselectivity.
These
products
can
serve
as
linchpins
synthesis
pharmaceutically
valuable
motifs.
Mechanistic
studies
indicate
that
formation
occurs
by
exciting
charge-transfer
complex
templated
protein.
Precise
control
over
orientation
molecules
within
potentially
accounts
observed
The
work
expands
types
motifs
be
prepared
using
photoenzymatic
catalysis.
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(10), P. 2062 - 2067
Published: March 7, 2024
The
use
of
readily
available
and
diverse
sulfamoyl
chlorides
for
synthesizing
sulfonamide
compounds
presents
an
intriguing,
yet
significantly
underexplored
strategy.
Activating
via
single-electron
reduction
poses
challenges
due
to
their
high
potential.
Alternatively,
the
SO2–Cl
bond
in
could
be
cleaved
by
XAT.
However,
existing
methodologies
have
been
limited
either
photocatalyst
or
monofunctionalization
activated
alkenes.
Here,
we
report
a
regioselective
sulfamoyl-oximation
alkenes
involving
activation
through
HAT
XAT
relay
strategy
photocatalyst-free
way.
key
this
success
lies
dual
roles
tert-butyl
nitrite
(TBN),
which
not
only
serves
as
source
oximes
but
also
acts
reagent
generate
crucial
reactive
species.
exclusion
metal
catalysts
photosensitizers
utilizing
light
energy
renders
protocol
versatile
universally
applicable
broad
range
structurally
oxime-containing
alkyl
sulfonamides.