Angewandte Chemie,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 4, 2024
Abstract
The
recent
development
of
photoredox
and
energy
transfer
catalysis
has
led
to
a
significant
expansion
visible‐light‐driven
chemical
transformations.
These
methods
have
demonstrated
exceptional
efficiency
in
converting
wide
range
substrates
into
radical
intermediates
generating
open‐shell
catalytic
species.
However,
the
simplification
systems
direct
generation
highly
reactive
organocatalysts
through
visible‐light
irradiation
from
stable
precatalysts
remains
largely
an
unrealized
goal.
This
challenge
is
mainly
due
limited
availability
that
are
responsive
visible
light.
Herein,
we
introduce
new
class
bench‐stable
dicationic
disulfuranes,
which
release
thiyl
radicals
upon
blue‐light
excitation.
Spectroscopic
computational
studies
reveal
this
reactivity
arises
combination
structural
features
intermolecular
interactions.
family
molecules
been
employed
catalyze
cascades
previously
incompatible
with
conditions,
enabling
efficient
formation
1,2‐dioxolanes
1,3‐hydroxyketones
excellent
yields
short
reaction
times.
Science,
Год журнала:
2023,
Номер
382(6674), С. 1056 - 1065
Опубликована: Ноя. 30, 2023
The
development
of
functionally
distinct
catalysts
for
enantioselective
synthesis
is
a
prominent
yet
challenging
goal
synthetic
chemistry.
In
this
work,
we
report
family
chiral
N-heterocyclic
carbene
(NHC)-ligated
boryl
radicals
as
that
enable
catalytic
asymmetric
radical
cycloisomerization
reactions.
can
be
generated
from
easily
prepared
NHC-borane
complexes,
and
the
broad
availability
NHC
component
provides
substantial
benefits
stereochemical
control.
Mechanistic
studies
support
cycle
comprising
sequence
addition,
hydrogen
atom
transfer,
cyclization,
elimination
catalyst,
wherein
subunit
determines
enantioselectivity
cyclization.
This
catalysis
allows
construction
valuable
heterocyclic
products
simple
starting
materials.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
11(4), С. 1232 - 1250
Опубликована: Дек. 28, 2023
Recent
advances
in
HAT-induced
C(sp
3
)–H
functionalizations
triggered
by
radical
addition
to
alkynes,
including
5-
exo-trig
,
endo-trig
4-
and
6-
cyclization
cascades,
intermolecular
functionalizations,
are
summarized.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(25)
Опубликована: Апрель 9, 2024
Abstract
Cascade
radical
cyclization
constitutes
an
atom‐
and
step‐economic
route
for
rapid
assembly
of
polycyclic
molecular
skeletons.
Although
array
redox‐active
metal
catalysts
has
recently
shown
robust
applications
in
enabling
various
catalytic
cascade
processes,
the
use
free
organic
as
catalyst,
which
is
capable
triggering
strategically
distinct
cascades,
rarely
been
developed.
Here,
we
disclosed
that
benzimidazolium‐based
N
‐heterocyclic
carbene
(NHC)‐boryl
catalyzing
reactions
both
intra‐
intermolecular
pathways,
assembling
[5,5]
fused
bicyclic
[6,6,6]
tricyclic
molecules,
respectively.
The
start
with
chemo‐
regioselective
addition
boryl
catalyst
to
a
tethered
alkene
or
alkyne
moiety,
followed
by
either
intramolecular
formal
[3+2]
[2+2+2]
cycloaddition
process
construct
bicyclo[3.3.0]octane
tetrahydrophenanthridine
skeletons,
Eventually,
β‐elimination
occurs
release
completing
cycle.
High
excellent
diastereoselectivity
achieved
under
substrate
control.
Organic Letters,
Год журнала:
2024,
Номер
26(25), С. 5341 - 5346
Опубликована: Июнь 14, 2024
An
unprecedented
VCP-CP
(vinylcyclopropane-cyclopentene)
rearrangement
approach
has
been
established
herein
by
virtue
of
the
pyridine-boronyl
radical
catalyzed
intramolecular
ring
expansions.
This
metal-free
pathway
harnesses
readily
available
catalysts
and
unactivated
vinylcyclopropane
starting
materials,
providing
an
array
cyclopentene
derivatives
chemoselectively
under
relatively
mild
conditions.
Mechanistic
studies
support
idea
that
boronyl
engages
in
generation
allylic/ketyl
species,
thus
inducing
opening
cyclopropanes
following
cyclization
processes.
Abstract
Transition‐metal‐catalyzed
radical
relay
cross‐coupling
reactions
of
1,3‐dienes
have
recently
emerged
as
one
the
most
powerful
methods
for
construction
structurally
diverse
allylic
compound
in
a
single
chemical
step.
However,
there
still
has
been
limited
success
expanding
substrate
scope
precursors
and
coupling
partners,
well
exploring
catalytic
asymmetric
variants.
Herein,
we
report
copper‐catalyzed
enantioselective
three‐component
1,2‐alkylesterification
using
cycloalkyl
hydroperoxides
carbonyl‐containing
alkyl
sources
carboxylic
acids
O‐nucleophiles
under
mild
redox‐neutral
conditions.
This
protocol
features
broad
good
functional
group
tolerance
with
respect
to
each
component,
providing
practical
access
variety
distally
keto‐functionalized
esters
high
enantioselectivity.
Mechanistic
studies
suggest
involvement
sequential
C−O
this
reaction.
Angewandte Chemie,
Год журнала:
2024,
Номер
136(25)
Опубликована: Апрель 9, 2024
Abstract
Cascade
radical
cyclization
constitutes
an
atom‐
and
step‐economic
route
for
rapid
assembly
of
polycyclic
molecular
skeletons.
Although
array
redox‐active
metal
catalysts
has
recently
shown
robust
applications
in
enabling
various
catalytic
cascade
processes,
the
use
free
organic
as
catalyst,
which
is
capable
triggering
strategically
distinct
cascades,
rarely
been
developed.
Here,
we
disclosed
that
benzimidazolium‐based
N
‐heterocyclic
carbene
(NHC)‐boryl
catalyzing
reactions
both
intra‐
intermolecular
pathways,
assembling
[5,5]
fused
bicyclic
[6,6,6]
tricyclic
molecules,
respectively.
The
start
with
chemo‐
regioselective
addition
boryl
catalyst
to
a
tethered
alkene
or
alkyne
moiety,
followed
by
either
intramolecular
formal
[3+2]
[2+2+2]
cycloaddition
process
construct
bicyclo[3.3.0]octane
tetrahydrophenanthridine
skeletons,
Eventually,
β‐elimination
occurs
release
completing
cycle.
High
excellent
diastereoselectivity
achieved
under
substrate
control.
Organic Chemistry Frontiers,
Год журнала:
2024,
Номер
11(23), С. 6712 - 6717
Опубликована: Янв. 1, 2024
A
visible
light-promoted
synthesis
route
to
fused
tetracyclic
skeletons
with
rich
sp
3
carbons
through
stepwise
radical
cycloadditions
and
further
cyclization
of
the
final
intermediates
adjacent
aromatic
rings
was
developed.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 4, 2024
Abstract
The
recent
development
of
photoredox
and
energy
transfer
catalysis
has
led
to
a
significant
expansion
visible‐light‐driven
chemical
transformations.
These
methods
have
demonstrated
exceptional
efficiency
in
converting
wide
range
substrates
into
radical
intermediates
generating
open‐shell
catalytic
species.
However,
the
simplification
systems
direct
generation
highly
reactive
organocatalysts
through
visible‐light
irradiation
from
stable
precatalysts
remains
largely
an
unrealized
goal.
This
challenge
is
mainly
due
limited
availability
that
are
responsive
visible
light.
Herein,
we
introduce
new
class
bench‐stable
dicationic
disulfuranes,
which
release
thiyl
radicals
upon
blue‐light
excitation.
Spectroscopic
computational
studies
reveal
this
reactivity
arises
combination
structural
features
intermolecular
interactions.
family
molecules
been
employed
catalyze
cascades
previously
incompatible
with
conditions,
enabling
efficient
formation
1,2‐dioxolanes
1,3‐hydroxyketones
excellent
yields
short
reaction
times.
