Organometallics,
Год журнала:
2024,
Номер
43(10), С. 1077 - 1084
Опубликована: Май 16, 2024
Nucleophilic
substitution
of
B–H
is
an
important
strategy
for
the
synthesis
carborane
derivatives.
Although
intermolecular
nucleophilic
has
been
widely
explored,
intramolecular
rarely
reported.
Herein,
we
synthesized
a
novel
carborane-fused
N-heteroaromatic
through
transition-metal-free
reaction
between
carboranyl
lithium
and
2,3-dichloroquinoxaline.
Two
C–Cl
substitutions
one
with
were
involved
in
this
transformation.
Instead
most
electron-deficient
B(3)–H
vertex,
selectively
occurred
on
B(4)–H
vertex.
This
method
provides
new
ring
compounds.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(18), С. 8371 - 8378
Опубликована: Май 2, 2022
Amination
of
carboranes
has
a
good
application
prospect
in
organic
and
pharmaceutical
synthesis.
However,
the
current
methods
used
for
this
transformation
suffer
from
limitations.
Herein,
we
report
practical
method
highly
regioselective
formation
B-N
bond
by
Pd(II)-catalyzed
B(9)-H
amination
o-
m-carboranes
hexafluoroisopropanol
(HFIP)
with
different
nitrogen
sources
under
air
atmosphere.
The
silver
salt
HFIP
solvent
play
critical
roles
present
protocol.
mechanistic
study
reveals
that
acts
as
Lewis
acid
to
promote
electrophilic
palladation
step
forming
heterobimetallic
active
catalyst
PdAg(OAc)3;
strong
hydrogen-bond-donating
ability
low
nucleophilicity
enhance
Pd(II).
It
is
believed
these
N-containing
are
potentially
great
importance
synthesis
new
pharmaceuticals.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(13), С. 7331 - 7342
Опубликована: Март 24, 2023
Herein,
we
present
a
chemically
robust
and
efficient
synthesis
route
for
B(9)-OH-o-carboranes
by
the
oxidation
of
o-carboranes
with
commercially
available
68%
HNO3
under
assistance
trifluoromethanesulfonic
acid
(HOTf)
hexafluoroisopropanol
(HFIP).
The
reaction
is
highly
wide
scope
carboranes,
selectivity
B(9)/B(8)
up
to
98:2.
success
this
transformation
relies
on
strong
electrophilicity
oxidizability
HNO3,
promoted
through
hydrogen
bonds
Brønsted
HOTf
solvent
HFIP.
Mechanism
studies
reveal
that
o-carborane
involves
an
initial
electrophilic
attack
atom
at
most
electronegative
B(9)
o-carborane.
In
transformation,
B-H
bond
nucleophilic
site,
which
different
from
substitution
reaction,
where
boron
site.
Therefore,
oxidation-reduction
mild
conditions
in
N(V)
→
N(III)
H(-I)
H(I).
derivatization
9-OH-o-carborane
was
further
examined,
carboranyl
group
successfully
introduced
amino
acid,
polyethylene
glycol,
biotin,
deoxyuridine,
saccharide.
Undoubtedly,
approach
provides
selective
way
rapid
incorporation
carborane
moieties
into
small
molecules
application
neutron
capture
therapy,
requires
targeted
delivery
boron-rich
groups.
Nature Communications,
Год журнала:
2024,
Номер
15(1)
Опубликована: Апрель 8, 2024
Abstract
Icosahedral
carboranes,
C
2
B
10
H
12
,
have
long
been
considered
to
be
aromatic
but
the
extent
of
conjugation
between
these
clusters
and
their
substituents
is
still
being
debated.
m
-
p
-Carboranes
are
compared
with
-phenylenes
as
conjugated
bridges
in
optical
functional
chromophores
a
donor
an
acceptor
here.
The
absorption
fluorescence
data
for
both
carboranes
from
experimental
techniques
(including
femtosecond
transient
absorption,
time-resolved
broadband
upconversion)
show
that
emission
processes
involve
strong
intramolecular
charge
transfer
via
carborane
cluster.
From
quantum
chemical
calculations
on
systems,
process
depends
relative
torsional
angles
groups
where
overlap
two
frontier
orbitals
exists
bridging
Chemical Science,
Год журнала:
2024,
Номер
15(13), С. 4839 - 4845
Опубликована: Янв. 1, 2024
A
range
of
novel
o
-carboranyl
substituted
boron
compounds
have
been
synthesized
through
reactions
between
an
-carborane-fused
aminoborirane
and
various
organic
azides.
The
reaction
selectivity
mechanisms
were
studied
using
DFT
calculations.
Inorganic Chemistry,
Год журнала:
2022,
Номер
61(23), С. 8879 - 8886
Опубликована: Июнь 1, 2022
The
iminoboryl
o-carboranes
(Me3Si)-Cb-B≡N-R
(Cb
=
B10C2H10,
3a,
R
SiMe3;
3b,
tBu)
have
been
successfully
synthesized
by
tetrahydrofuran
(THF)-promoted
isomerization
from
the
corresponding
o-carborane-fused
aminoboriranes
Cb{BN(SiMe3)R}
(2).
synthetic
protocol
of
previously
reported
borirane
2a
was
optimized.
Cb{BN(SiMe3)tBu}
(2b)
and
iminoboranes
3a
3b
were
fully
characterized
NMR,
IR,
single-crystal
X-ray
diffraction
analyses.
isomerizes
more
readily
than
2b.
kinetics
study
revealed
a
bimolecular
mechanism
between
THF,
which
is
in
good
agreement
with
computationally
proposed
reaction
pathway.
title
compounds
are
thermally
robust,
but
compound
dimerized
presence
catalytic
amount
tBuNC
to
give
cyclodimer
4.
Quick
equilibrium
4
isonitrile
adduct
4·tBuNC
observed
solution.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(36)
Опубликована: Июнь 17, 2022
Abstract
Herein,
we
report
the
facile
synthesis
of
a
three‐dimensional
(3D)
inorganic
analogue
9,10‐diazido‐9,10‐dihydrodiboraantracene,
which
turned
out
to
be
monomer
in
both
solid
and
solution
state,
thermally
stable
up
230
°C,
representing
rare
example
azido
borane
with
boosted
Lewis
acidity
stability
one.
Apart
from
classical
acid‐base
Staudinger
reactions,
E−H
bond
activation
(E=B,
Si,
Ge)
was
investigated.
While
reaction
B−H
(9‐borabicyclo[3.3.1]nonane)
led
directly
1,1‐addition
on
N
α
upon
2
elimination,
Si−H
(Et
3
SiH,
PhMe
SiH)
proceeded
stepwise
via
1,2‐addition,
key
intermediates
5
int
6
being
isolated
characterized.
In
contrast,
cooperative
Ge−H
reversible
stayed
at
1,2‐addition
step.
Inorganic Chemistry,
Год журнала:
2022,
Номер
61(45), С. 18275 - 18284
Опубликована: Ноя. 4, 2022
Three-dimensional
(3D)
analogues
of
9-borafluorenes,
(C2B10H10)2BR
(R
=
Cl
(1),
Br
(2),
H
(3,
merely
as
ether
or
silane
adduct),
phenyl
(4),
mesityl
(5)),
were
synthesized
and
fully
characterized.
Gutmann–Beckett
computational
fluoride/hydride
ion
affinity
(FIA/HIA)
studies
confirmed
the
Lewis
superacidity
1–4,
with
acidity
1–3
being
higher
than
that
corresponding
3D
9,10-diboraanthracenes
(DBA).
The
group
C4B
borole
unit
are
nearly
coplanar
in
solid
state,
while
rotation
5
is
hindered,
forcing
to
adopt
a
large
C4B/Mes
dihedral
angle,
which
leads
distinct
properties:
air-stable
bluish-violet
fluorescence
arising
from
intramolecular
charge-transfer
(ICT)
transition.
29Si
NMR
spectra
indicated
high
silylium
cation
character
3·Et3SiH.
reaction
4
Ph3CBr
yielded
(Ph3C)+[(C2B10H10)2B(Ph)Br]−
(6).
4/PPh3
pair
was
capable
splitting
dihydrogen
Si–H
bond
triethylsilane.
