Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 8, 2024
The
2,2-difluoroethyl
group
is
an
important
lipophilic
hydrogen
bond
donor
in
medicinal
chemistry,
but
its
incorporation
into
small
molecules
often
challenging.
Herein,
we
demonstrate
electrophilic
2,2-difluoroethylation
of
thiol,
amine
and
alcohol
nucleophiles
with
a
hypervalent
iodine
reagent,
(2,2-difluoro-ethyl)(aryl)iodonium
triflate,
via
proposed
ligand
coupling
mechanism.
This
transformation
offers
complementary
strategy
to
existing
methods
allows
access
wide
range
2,2-difluoroethylated
nucleophiles,
including
the
drugs
Captopril,
Normorphine
Mefloquine.
Macromolecules,
Год журнала:
2022,
Номер
55(13), С. 5756 - 5765
Опубликована: Июнь 27, 2022
Cationic
polymerization
of
isobutyl
vinyl
ether
(IBVE)
was
investigated
using
Schreiner's
thiourea
(STU)
combined
with
Im-TEPB
bearing
a
2-iodoimidazolium
cation
and
noncoordinating
borate
anion.
Both
the
CF3CO2H
adduct
HCl
IBVE
had
ability
to
initiate
polymerization,
but
number-averaged
molecular
weight
rather
low
compared
theoretical
value
distribution
fairly
broad
(Mw/Mn
>
2.6).
On
other
hand,
fast
cationic
p-methoxystyrene
(pMOS,
50
equiv
relative
pMOS·HCl)
proceeded
STU/Im-TEPB
cocatalysts,
giving
rise
poly(pMOS)
Mn
=
4580
Mw/Mn
1.38.
STU/Im-TfO
exhibited
decreased
activity
due
coordination
trifluoromethanesulfonate
counteranion
NH
group
STU,
which
supported
by
NMR
spectrum,
DFT
calculation,
UV–vis
titration
experiment.
The
could
be
roughly
regulated
cocatalysis
between
2400
7500
monomer
feed
ratio
keeping
below
1.41,
although
these
values
were
lower
than
ones
probably
unignorable
chain-transfer
reaction.
kinetics
revealed
that
consumption
rate
depends
on
concentration
reveals
catalytic
function
STU/Im-TEPB.
Kinetic
data
based
on
1
H
NMR
monitoring
and
computational
studies
indicate
that
in
solution,
pyrazole-containing
iodonium
triflates
silver(I)
triflate
bind
to
each
other,
such
an
interplay
results
the
decrease
of
total
catalytic
activity
mixture
these
Lewis
acids
compared
separate
catalysis
Schiff
condensation,
imine-isocyanide
coupling,
or
nucleophilic
attack
a
triple
carbon-carbon
bond.
Moreover,
kinetic
cooperation
with
prevention
decomposition
salts
during
reaction
progress.
XRD
study
confirms
coordinates
center
via
pyrazole
N
atom
produce
rare
example
pentacoordinated
trigonal
bipyramidal
dinuclear
complex
featuring
cationic
ligands.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(5), С. 2916 - 2925
Опубликована: Фев. 19, 2024
Sulfonium,
selenonium,
telluronium,
and
iodonium
cyanoborohydrides
have
been
synthesized,
isolated,
fully
characterized
by
various
methods,
including
single-crystal
X-ray
diffraction
(XRD)
analysis.
The
quantum
theory
of
atoms
in
molecules'
analysis
based
on
the
XRD
data
indicated
that
hydride···σ-hole
short
contacts
observed
crystal
structures
each
compound
a
purely
noncovalent
nature.
telluronium
provide
significantly
higher
rate
model
reaction
imine
hydrogenation
compared
with
sodium
tetrabutylammonium
cyanoborohydrides.
Based
NMR
high-resolution
electrospray
ionization
mass
spectrometry
indicating
progress
is
accompanied
cation
reduction,
mechanism
involving
intermediate
formation
elusive
onium
hydrides
has
proposed
as
an
alternative
to
conventional
electrophilic
activation
moiety
its
ligation
cation's
σ-hole.
Abstract
The
experimentally
obtained
kinetic
data
has
indicated
the
existence
of
a
synergetic
cocatalytic
effect
provided
by
an
iodonium
salt
in
base‐catalyzed
Knoevenagel
condensation.
diphenyliodonium
triflate
serving
as
halogen
bond‐donating
Lewis
acid
provides
higher
than
zinc(II)
or
triflic
serving,
respectively,
metal
cation‐based
and
Brønsted
acid.
Such
remains
same
for
broad
scope
carbonyl
compounds
covering
aldehydes
featuring
electron‐withdrawing
electron‐donating
substituents,
well
ketone
involved
reaction.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 8, 2024
The
2,2-difluoroethyl
group
is
an
important
lipophilic
hydrogen
bond
donor
in
medicinal
chemistry,
but
its
incorporation
into
small
molecules
often
challenging.
Herein,
we
demonstrate
electrophilic
2,2-difluoroethylation
of
thiol,
amine
and
alcohol
nucleophiles
with
a
hypervalent
iodine
reagent,
(2,2-difluoro-ethyl)(aryl)iodonium
triflate,
via
proposed
ligand
coupling
mechanism.
This
transformation
offers
complementary
strategy
to
existing
methods
allows
access
wide
range
2,2-difluoroethylated
nucleophiles,
including
the
drugs
Captopril,
Normorphine
Mefloquine.
