Synlett,
Год журнала:
2022,
Номер
33(18), С. 1819 - 1825
Опубликована: Окт. 14, 2022
Abstract
Vicinal
dihalides
not
only
emerge
as
reactive
intermediates
in
synthetic
organic
chemistry,
but
also
are
extensively
existing
bioactive
marine
natural
products.
The
dihalogenation
of
alkenes
is
the
most
direct
and
effective
method
for
synthesis
vicinal
dihalides.
Because
there
always
an
exchange
process
between
chiral
haloniums
unreacted
olefins
to
cause
racemization,
development
catalytic
enantioselective
great
difficulty.
Recently,
progress
has
been
made
asymmetric
manner.
However,
a
lack
related
review
discussions
mechanisms
reaction
systems.
This
aimed
at
summarizing
alkenes,
including
1,2-dichlorination,
1,2-dibromination,
1,2-difluorination,
which
expected
encourage
more
researchers
participate
this
field.
1
Introduction
2
Enantioselective
1,2-Dichlorination
1,2-Dibromination
Alkenes
2.1
Chiral-Boron-Complex-Promoted
2.2
Organocatalytic
Asymmetric
2.3
Chiral-Titanium-Complex-Catalyzed
1,2-Dihalogenation
3
Chiral-Iodide-Catalyzed
Oxidative
1,2-Difluorination
4
Summary
Outlook
Chemistry - A European Journal,
Год журнала:
2021,
Номер
27(69), С. 17341 - 17345
Опубликована: Окт. 14, 2021
The
first
example
for
the
electrochemical
cis-dichlorination
of
alkenes
is
presented.
reaction
can
be
performed
with
little
experimental
effort
by
using
phenylselenyl
chloride
as
catalyst
and
tetrabutylammoniumchloride
supporting
electrolyte,
which
also
acts
nucleophilic
reagent
S
Physical Chemistry Chemical Physics,
Год журнала:
2021,
Номер
23(45), С. 25572 - 25589
Опубликована: Янв. 1, 2021
Haliranium
ions
are
intermediates
often
involved
in
complex
cyclisations,
where
their
structure
allows
for
control
over
stereospecific
outcomes.
Extending
previous
studies
into
and
reactivity
the
gas
phase,
this
work
focuses
on
bimolecular
of
ethyl
bromiranium
iodiranium
with
cyclic
alkenes.
The
products
observed
via
mass
spectrometry
were
broadly
attributed
to
either
addition
by
cyclohexene
at
iranium
carbon
or
attack
heteroatom
undergo
associative
π-ligand
exchange.
model
proposed
was
supported
both
kinetic
experiments
DFT
calculations,
rate
parent
ion
consumption
proceeded
collision
(Br:
k2
=
1.25
×
10-9
I:
1.28
cm3
molecule-1
s-1)
subsequent
partitioning
dependent
relative
stability
initial
relatively
large
barriers
present
pathway.
Exploration
effect
cycloalkene
ring
strain
conducted
a
series
crossover
50
:
mixtures
cis-cyclooctene
styrene,
outcomes
competing
relief
gained
reaction
each
neutral.
nature
exchange
transition
state
determined
be
pseudocoarctate
following
natural
bond
orbital
(NBO)
anisotropy
induced
current
density
(ACID)
analysis.
The Journal of Physical Chemistry Letters,
Год журнала:
2023,
Номер
14(2), С. 460 - 467
Опубликована: Янв. 9, 2023
Whether
the
structure
of
C6H6X
(X
=
halogen),
an
intermediate
in
halogenation
benzene,
is
open
or
a
bridged
form
has
been
debated.
We
produced
Br
to
react
with
C6H6
upon
photolysis
situ
Br2/C6H6/p-H2
matrix
at
3.2
K.
In
contrast
C6H6Cl
σ-complex
reported
previously,
observed
infrared
spectrum
indicates
that
C6H6Br
open-form
π-complex.
Furthermore,
lines
two
CH
out-of-plane
bending
modes
associated
mainly
even-
and
odd-numbered
carbons,
predicted
near
672
719
cm–1,
merged
into
broad
line
697.3
indicating
these
become
nearly
equivalent
as
migrates
from
one
carbon
atom
another.
Quantum-chemical
calculations
support
benzene
ring
performs
bevel-gear-type
rotation
respect
Br.
Observation
only
trans-ortho-
trans-para-C6H6Br2
suggests
this
gear-type
motion
allows
additional
attack
opposite
side
C6H6Br.
Synlett,
Год журнала:
2022,
Номер
33(18), С. 1819 - 1825
Опубликована: Окт. 14, 2022
Abstract
Vicinal
dihalides
not
only
emerge
as
reactive
intermediates
in
synthetic
organic
chemistry,
but
also
are
extensively
existing
bioactive
marine
natural
products.
The
dihalogenation
of
alkenes
is
the
most
direct
and
effective
method
for
synthesis
vicinal
dihalides.
Because
there
always
an
exchange
process
between
chiral
haloniums
unreacted
olefins
to
cause
racemization,
development
catalytic
enantioselective
great
difficulty.
Recently,
progress
has
been
made
asymmetric
manner.
However,
a
lack
related
review
discussions
mechanisms
reaction
systems.
This
aimed
at
summarizing
alkenes,
including
1,2-dichlorination,
1,2-dibromination,
1,2-difluorination,
which
expected
encourage
more
researchers
participate
this
field.
1
Introduction
2
Enantioselective
1,2-Dichlorination
1,2-Dibromination
Alkenes
2.1
Chiral-Boron-Complex-Promoted
2.2
Organocatalytic
Asymmetric
2.3
Chiral-Titanium-Complex-Catalyzed
1,2-Dihalogenation
3
Chiral-Iodide-Catalyzed
Oxidative
1,2-Difluorination
4
Summary
Outlook
