Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(26), С. 11888 - 11896
Опубликована: Июнь 23, 2022
Ketone–olefin
coupling
reactions
are
common
methods
for
the
formation
of
carbon–carbon
bonds.
This
reaction
class
typically
requires
stoichiometric
or
super
quantities
metal
reductants,
and
catalytic
variations
limited
in
application.
Photoredox
catalysis
has
offered
an
alternative
method
toward
ketone–olefin
reactions,
although
most
scope
to
easily
reducible
aromatic
carbonyl
compounds.
Herein,
we
describe
a
mild,
metal-free
using
excited-state
acridine
radical
reductant
as
photoredox
catalyst.
We
demonstrate
both
intramolecular
intermolecular
couplings
aliphatic
ketones
aldehydes.
Mechanistic
evidence
is
also
presented
supporting
"olefin
first"
mechanism.
Angewandte Chemie International Edition,
Год журнала:
2019,
Номер
59(1), С. 74 - 108
Опубликована: Май 22, 2019
Abstract
Radical–radical
couplings
are
mostly
nearly
diffusion‐controlled
processes.
Therefore,
the
selective
cross‐coupling
of
two
different
radicals
is
challenging
and
not
a
synthetically
valuable
transformation.
However,
if
have
lifetimes
they
generated
at
equal
rates,
will
become
dominant
process.
This
high
cross‐selectivity
based
on
kinetic
phenomenon
called
persistent
radical
effect
(PRE).
In
this
Review,
an
explanation
PRE
supported
by
simulations
simple
model
systems
provided.
Radical
stabilities
discussed
within
context
their
lifetimes,
various
examples
PRE‐mediated
radical–radical
in
synthesis
summarized.
It
shown
that
restricted
to
coupling
with
transient
radical.
If
one
partner
longer‐lived
than
other
radical,
operates
achieved.
important
point
expands
scope
chemistry.
The
Review
divided
into
parts,
namely
1)
or
organic
2)
“radical–metal
crossover
reactions”;
here,
metal‐centered
species
more
generally
transition‐metal
complexes
able
react
discussed—a
field
has
flourished
recently.
Chemical Science,
Год журнала:
2019,
Номер
10(36), С. 8285 - 8291
Опубликована: Янв. 1, 2019
The
concept
of
reductive
radical-polar
crossover
(RRPCO)
reactions
has
recently
emerged
as
a
valuable
and
powerful
tool
to
overcome
limitations
both
radical
traditional
polar
chemistry.
Journal of the American Chemical Society,
Год журнала:
2019,
Номер
141(16), С. 6726 - 6739
Опубликована: Апрель 3, 2019
Historically
accessed
through
two-electron,
anionic
chemistry,
ketones,
alcohols,
and
amines
are
of
foundational
importance
to
the
practice
organic
synthesis.
After
placing
this
work
in
proper
historical
context,
Article
reports
development,
full
scope,
a
mechanistic
picture
for
strikingly
different
way
forging
such
functional
groups.
Thus,
carboxylic
acids,
once
converted
redox-active
esters
(RAEs),
can
be
utilized
as
formally
nucleophilic
coupling
partners
with
other
derivatives
(to
produce
ketones),
imines
benzylic
amines),
or
aldehydes
alcohols).
The
reactions
uniformly
mild,
operationally
simple,
and,
case
ketone
synthesis,
broad
scope
(including
several
applications
simplification
synthetic
problems
parallel
synthesis).
Finally,
an
extensive
study
synthesis
is
performed
trace
elementary
steps
catalytic
cycle
provide
end-user
clear
understandable
rationale
selectivity,
role
additives,
underlying
driving
forces
involved.
Journal of the American Chemical Society,
Год журнала:
2019,
Номер
141(19), С. 7709 - 7714
Опубликована: Апрель 29, 2019
Metal-hydride
hydrogen
atom
transfer
(MHAT)
functionalizes
alkenes
with
predictable
branched
(Markovnikov)
selectivity.
The
breadth
of
these
transformations
has
been
confined
to
π-radical
traps;
no
sp3
electrophiles
have
reported.
Here
we
describe
a
Mn/Ni
dual
catalytic
system
that
hydroalkylates
unactivated
olefins
alkyl
halides,
yielding
aliphatic
quaternary
carbons.
ACS Catalysis,
Год журнала:
2019,
Номер
10(2), С. 1621 - 1627
Опубликована: Дек. 18, 2019
The
direct
conversion
of
feedstock
chemicals
into
value-added
products
is
broad
interest
in
chemical
research.
Herein,
we
present
a
regioselective
and
diastereoselective
three-component
dialkylation
1,3-dienes
with
Hantzsch
esters
aldehydes
for
the
synthesis
homoallylic
alcohols.
reaction
enabled
by
dual
photoredox
chromium
catalysis
can
also
be
performed
enantioselectively
employing
chromium-bisoxazoline
complexes.
ACS Catalysis,
Год журнала:
2021,
Номер
11(9), С. 5572 - 5585
Опубликована: Апрель 22, 2021
Atom-efficient
processes
that
occur
via
addition,
redistribution
or
removal
of
hydrogen
underlie
many
large
volume
industrial
and
pervade
all
segments
chemical
industry.
Although
carbonyl
addition
is
one
the
oldest
most
broadly
utilized
methods
for
C-C
bond
formation,
delivery
non-stabilized
carbanions
to
compounds
has
relied
on
premetalated
reagents
metallic/organometallic
reductants,
which
pose
issues
safety
challenges
vis-à-vis
implementation.
Catalytic
reductive
couplings
promoted
hydrogenation,
transfer
hydrogenation
auto-transfer
allow
abundant
unsaturated
hydrocarbons
serve
as
substitutes
organometallic
reagents,
enabling
formation
in
absence
stoichiometric
metals.
This
perspective
(a)
highlights
past
milestones
catalytic
auto-transfer,
(b)
summarizes
current
enantioselective
couplings,
(c)
describes
future
opportunities
based
patterns
reactivity
animate
transformations
this
type.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(18), С. 7953 - 7959
Опубликована: Апрель 27, 2022
We
demonstrate
Markovnikov
hydroalkoxylation
of
unactivated
alkenes
using
alcohols
through
a
triple
catalysis
consisting
photoredox,
cobalt,
and
Brønsted
acid
catalysts
under
visible
light
irradiation.
The
realizes
three
key
elementary
steps
in
single
catalytic
cycle:
(1)
Co(III)
hydride
generation
by
photochemical
reduction
Co(II)
followed
protonation,
(2)
metal
hydrogen
atom
transfer
(MHAT)
hydride,
(3)
oxidation
the
alkyl
complex
to
Co(IV).
precise
control
protons
electrons
allows
elimination
strong
acids
external
reductants/oxidants
that
are
required
conventional
methods.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(9), С. 5363 - 5369
Опубликована: Фев. 21, 2023
Over
the
past
decade,
bicyclo[1.1.1]pentane
(BCP)
motifs
have
come
to
fore
as
valuable
pharmaceutical
bioisosteres
of
para-disubstituted
benzenes.
However,
limited
approaches
and
requisite
multistep
syntheses
useful
BCP
building
blocks
are
hampering
early
discovery
research
in
medicinal
chemistry.
Herein
we
report
development
a
modular
strategy
for
divergent
preparation
functionalized
alkylamines.
In
this
process,
general
method
introduce
fluoroalkyl
groups
scaffolds
using
readily
available
easy-to-handle
sulfinate
salts
was
also
developed.
Moreover,
can
be
extended
S-centered
radicals
incorporation
sulfones
thioethers
into
core.
Overall,
multicomponent
enables
rapid
construction
BCP-type
applications
drug
discovery.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(4), С. 2351 - 2357
Опубликована: Янв. 17, 2024
Cross-coupling
catalysts
typically
react
and
unite
functionally
distinct
partners
via
sequential
inner-sphere
elementary
steps:
coordination,
migratory
insertion,
reductive
elimination,
etc.
Here,
we
report
a
single
catalyst
that
cross-couples
styrenes
benzyl
bromides
iterative
outer-sphere
metal–ligand-carbon
interactions.
Each
partner
forms
stabilized
radical
intermediate,
yet
heterocoupled
products
predominate.
The
system
is
redox-neutral
and,
thus,
avoids
exogenous
oxidants,
resulting
in
simple
scalable
conditions.
Numerous
variations
of
alkene
hydrobenzylation
are
made
possible,
including
access
to
the
privileged
heterodibenzyl
(1,2-diarylethane)
motif
challenging
quaternary
carbon
variants.
