Symmetry,
Год журнала:
2022,
Номер
14(5), С. 989 - 989
Опубликована: Май 12, 2022
The
intramolecular
halocyclization
of
alkenes
possessing
an
internal
heteroatom
nucleophile
leads
to
multifunctional
heterocycles
which
are
useful
versatile
intermediates
in
organic
synthesis.
asymmetric
chlorocyclisation
2-substituted
allylic
amides
gives
access
chiral
oxazolines
bearing
a
chloromethyl
moiety
for
further
synthetic
manipulation.
literature
reports
on
this
transformation
involve
complex
syntheses
the
and
cryogenic
temperatures
achieving
high
enantioselectivities
organocatalyzed
step.
Based
Heck
reaction
aryl
bromides
Boc-protected
allylamine
or
benzamides,
we
developed
practical
synthesis
that
does
not
require
chromatography
accomplished
their
with
24–92%ee
under
conditions
(5
°C,
CpME)
catalyzed
by
(S)-(+)-DTBM-SEGPHOS.
In
addition,
using
appropriately
substituted
substrates,
generated
Hammett
plots
formulated
consistent
mechanism
involves
two
competing
modes
formation
haliranium
intermediate
whose
relative
kinetics
governed
electronic
properties
substrate.
Nature Communications,
Год журнала:
2023,
Номер
14(1)
Опубликована: Янв. 23, 2023
Electricity-driven
asymmetric
catalysis
is
an
emerging
powerful
tool
in
organic
synthesis.
However,
induction
so
far
has
mainly
relied
on
forming
strong
bonds
with
a
chiral
catalyst.
Asymmetry
induced
by
weak
interactions
catalyst
electrochemical
medium
remains
challenging
due
to
compatibility
issues
related
solvent
polarity,
electrolyte
interference,
etc.
Enabled
properly
designed
phase-transfer
strategy,
here
we
have
achieved
two
efficient
electricity-driven
catalytic
bromocyclization
processes
ion-pairing
interaction.
The
combined
use
of
and
phosphate
catalyst,
together
NaBr
as
the
bromine
source,
constitutes
key
advantages
over
conventional
chemical
oxidation
approach.
Synergy
multiple
events,
including
anodic
oxidation,
ion
exchange,
phase
transfer,
bromination,
inhibition
Br2
decomposition
NaHCO3,
proved
critical
success.
Chemical Science,
Год журнала:
2024,
Номер
15(19), С. 7187 - 7197
Опубликована: Янв. 1, 2024
The
halolactonization
reaction
provides
rapid
access
to
densely
functionalized
lactones
from
unsaturated
carboxylic
acids.
endo/exo
regioselectivity
of
this
cyclization
is
primarily
determined
by
the
electronic
stabilization
alkene
substituents,
thus
making
it
inherently
dependent
on
substrate
structures.
Therefore
method
often
affords
one
type
halolactone
regioisomer
only.
Herein,
we
introduce
a
simple
and
efficient
for
regioselectivity-switchable
bromolactonization
reactions
mediated
HFIP
solvent.
Two
sets
conditions
were
developed,
each
forming
endo-products
or
exo-products
in
excellent
regioselectivity.
A
combination
computational
experimental
mechanistic
studies
not
only
confirmed
crucial
role
HFIP,
but
also
revealed
formation
under
kinetic
control
thermodynamic
control.
This
study
paves
way
future
work
use
perfluorinated
solvents
dictate
outcomes
organic
synthesis.
Chemical Science,
Год журнала:
2024,
Номер
15(16), С. 6130 - 6140
Опубликована: Янв. 1, 2024
The
halocyclization
reaction
represents
one
of
the
most
common
methodologies
for
synthesis
heterocyclic
molecules.
Many
efforts
have
been
made
to
balance
relationship
between
structure,
reactivity
and
selectivity,
including
design
new
electrophilic
halogenation
reagents
utilization
activating
strategies.
However,
discovering
universal
or
strategies
remains
challenging
due
case-by-case
practice
different
substrates
cyclization
models.
Here
we
report
an
intramolecular
chaperone-assisted
dual-anchoring
activation
(ICDA)
model
halocyclization,
taking
advantage
non-covalent
orientation
as
driving
force.
This
protocol
allows
a
practical,
catalyst-free
rapid
approach
access
seven
types
small-sized,
medium-sized,
large-sized
units
realize
polyene-like
domino
halocyclizations,
exemplified
by
nearly
90
examples,
risk-reducing
flow
gram-scale
synthesis.
DFT
studies
verify
crucial
role
ICDA
in
affording
suitable
preorganization
transition
state
stabilization
X
Advanced Synthesis & Catalysis,
Год журнала:
2022,
Номер
364(23), С. 3974 - 4005
Опубликована: Окт. 20, 2022
Abstract
Halogen
(fluorine,
chlorine,
bromine,
iodine)
or
chalcogen
(sulfur,
selenium)‐containing
heterocycles
are
widely
recognized
as
key
building
blocks
in
many
natural
products
and
bioactive
targets.
Catalytic
asymmetric
halogenation/chalcogenation
of
carbon‐carbon
unsaturated
bonds
via
onium
ion
transformations
efficient
methods
to
obtain
diverse
chiral
heterocyclic
backbones.
In
the
past
few
years,
catalytic
enantioselective
versions
halo/thio/seleno‐functionalizations
with
various
halogen
electrophiles
have
experienced
constant
development.
This
review
highlights
those
advances
preparing
functionalized
promoted
by
organocatalysts
metal‐based
catalysts.
magnified
image
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(36), С. 16490 - 16501
Опубликована: Сен. 2, 2022
Electrophilic
halogenation
of
alkenes
is
a
powerful
transformation
offering
convenient
route
for
the
construction
valuable
functionalized
molecules.
However,
as
highly
important
reaction
in
this
field,
catalytic
asymmetric
intermolecular
iodinative
difunctionalization
remains
formidable
challenge.
Herein,
we
report
that
an
efficient
Lewis
basic
chiral
sulfide-catalyzed
approach
enables
reaction.
By
approach,
challenging
substrates
such
γ,γ-disubstituted
allylic
sulfonamides
and
1,1-disubstituted
with
sulfonamide
unit
undergo
electrophilic
to
give
variety
iodine-functionalized
molecules
good
yields
excellent
enantio-
diastereoselectivities.
A
series
free
phenols
nucleophiles
are
successfully
incorporated
into
substrates.
Aside
from
phenols,
primary
secondary
alcohols,
fluoride,
azide
also
serve
nucleophiles.
The
obtained
iodinated
products
platform
molecule,
which
can
be
easily
transformed
various
compounds
α-aryl
ketones,
amines,
aziridines
via
rearrangement
or
substitution.
Mechanistic
studies
revealed
sulfide
catalyst
displays
superior
effect
on
control
reactivity
iodine
enantioselective
iodiranium
ion
intermediate
aggregates
might
formed
resting
state
reactions.
The Journal of Organic Chemistry,
Год журнала:
2025,
Номер
90(6), С. 2172 - 2179
Опубликована: Янв. 31, 2025
The
reaction
mechanism
and
the
enantioselectivity
of
Brønsted
acid/base
(trans-stilbene
diamine,
simplified
by
BAM)-catalyzed
CO2
fixation
with
homoallylic
amine
have
been
investigated
using
density
functional
theory
(DFT)
calculations.
proposed
involves
initial
activation
acid,
followed
nucleophilic
attack
on
to
form
a
carbamate
intermediate.
base
subsequently
deprotonates
intermediate
cyclic
product,
regenerating
acid
catalyst.
C-O
cyclization
is
enantio-determining
step.
hydrogen
bond
network
formed
catalyst
substrate,
similar
an
enzyme
pocket,
plays
key
role
in
stereoselectivity.
In
addition,
energy
decomposition
analysis
(EDA)
confirms
that
bonding
driven
orbital
electrostatic
attractions.
more
basic
BAM
(OMe
at
quinoline
7-position)
exhibits
enhanced
enantioselectivity.
Asymmetric
halogenation
for
efficient
construction
of
various
4H-3,1-benzoxazine
derivatives
with
excellent
functional
group
tolerance
using
readily
available
N-haloamides
as
the
halogen
source
and
ammonium
phosphate
salt
catalyst
under
mild
reaction
conditions
has
been
developed.
The
loading
could
be
reduced
to
1
mol
%
recycled
4
times
without
deterioration
in
reactivity
stereoselectivity.
Importantly,
this
process
features
a
column-purification-free
operation,
leading
green
atom-economical
preparation
chiral
benzoxazines
good
yields
high
enantioselectivities.
Abstract
The
catalytic
asymmetric
Friedel–Crafts
reactions
of
(hetero)arenes
represent
a
cornerstone
in
synthetic
chemistry
due
to
their
ability
efficiently
incorporate
aromatic
rings
into
complex
molecular
architectures.
This
account
presents
comprehensive
overview
recent
advancements
the
enantioselective
(hetero)arenes,
with
particular
focus
on
that
facilitate
introduction
multiple
C–C
bonds
via
iranium/irenium-ion-triggered
electrophilic
processes.
We
examine
detail
strategies
and
methodologies
employed
achieve
stereoselective
incorporation
unsaturated
bonds,
highlighting
construction
diverse
structural
scaffolds.
Additionally,
this
showcases
broad
range
applications
powerful
transformation
organic
synthesis.
1
Introduction
2
Catalytic
Enantioselective
Reactions
Thiiranium/Thiirenium
Ions
2.1
Arylthiiranium/Arylthiirenium-Ion-Triggered
2.2
Trifluoromethylthiiranium/Trifluoromethylthiirenium-Ion-Triggered
3
Haliranium
3.1
Chloriranium-Ion-Triggered
3.2
Bromiranium-Ion-Triggered
3.3
Iodiranium-Ion-Triggered
Asymmetric
Oxidative
Arylation
Alkenes
4
Conclusion
Outlook
