Chemical Science,
Journal Year:
2024,
Volume and Issue:
15(27), P. 10392 - 10401
Published: Jan. 1, 2024
A
Pd-catalyzed
cross-coupling
system
has
been
developed
to
achieve
vicinal
diamination
of
9,10-dibromo-carborane
with
NH-heterocycles
and
anilines.
These
products
can
be
further
converted
carborane-fused
six-
seven-membered
heterocycles.
Accounts of Chemical Research,
Journal Year:
2021,
Volume and Issue:
54(21), P. 4065 - 4079
Published: Oct. 24, 2021
ConspectusCarboranes
are
a
class
of
polyhedral
carbon-boron
molecular
clusters
featuring
three-dimensional
aromaticity,
which
often
considered
as
3D
analogues
benzene.
Their
unique
structural
and
electronic
properties
make
them
invaluable
building
blocks
for
applications
ranging
from
functional
materials
to
versatile
ligands
pharmaceuticals.
Thus,
selective
functionalization
carboranes
has
received
tremendous
research
interest.
In
earlier
days,
the
vast
majority
works
in
this
area
were
focused
on
cage
carbon
via
facile
deprotonation
CH,
followed
by
reaction
with
electrophiles.
On
contrary,
B-H
activation
is
very
challenging
since
10
bonds
o-carborane
similar,
how
achieve
desired
transformation
at
specific
boron
vertex
long-standing
issue.As
more
electronegative
than
boron,
property
results
different
charges
cage,
follow
order
B(3,6)-H
≪
B(4,5,7,11)-H
<
B(8,10)-H
B(9,12)-H.
We
thought
that
difference
may
trigger
favorite
interaction
proper
transition
metal
complex
bond
carborane,
could
be
utilized
solve
selectivity
issue.
Accordingly,
our
strategy
described
follows:
(1)
electron-rich
catalysts
good
most
electron-deficient
(connected
both
C-H
vertices);
(2)
relatively
B(8,9,10,12)-H
(with
no
bonding
either
(3)
directing-group-assisted
catalysis
appropriate
only
one
vertex),
whose
lie
middle
range
bonds.
This
been
successfully
applied
laboratory
other
groups
development
series
synthetic
routes
catalytic
carborane
resulting
synthesis
large
number
cage-boron-functionalized
derivatives
regioselective
fashion.
Subsequently,
significant
progress
emerging
made.In
2013
we
reported
tetrafluorination
o-carboranes
using
an
Pd(II)
salt,
[Pd(MeCN)4][BF4],
catalyst.
2014
disclosed
first
example
carboxy-directed
alkenylation
B(4)
promoted
Ir(III)
2017
presented
Ir(I)-catalyzed
diborylation
also
uncovered
Pd-catalyzed
asymmetric
chiral-at-cage
2018.
These
proof-of-principle
studies
have
greatly
stimulated
activities
enabled
catalysts.
so
far
developed
toolbox
methods
B-olefination,
-arylation,
-alkenylation,
-alkynylation,
-oxygenation,
-sulfenylation,
-borylation,
-halogenation,
-amination.
recently
expanded
base
catalysis.
As
field
progresses,
expect
will
invented,
detailed
Account
promote
these
efforts.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(18), P. 8371 - 8378
Published: May 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,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 14, 2025
Carboranyl
amines
are
distinct
from
typical
organic
amines.
Due
to
the
electronic
influence
of
carborane
cage,
they
have
low
nucleophilicity
and
reluctant
alkylate.
Moreover,
asymmetric
synthesis
chiral
carboranes
is
still
in
its
infancy.
Herein
we
achieved
first
catalytic
N-alkylation
o-carboranyl
amine,
providing
general
access
diverse
secondary
with
high
efficiency
enantioselectivity
under
mild
conditions.
For
time,
organocatalysis
was
introduced
chemistry.
Key
success
use
situ
generated
(naphtho-)quinone
methides
as
alkylating
reagents
suitable
acid
catalysts.
This
protocol
also
applicable
S-alkylation
1-SH-o-C2B10H11.
Control
experiments
kinetic
studies
provided
important
insights
into
reaction
mechanism,
which
likely
involves
rate-determining
generation
quinone
methide
followed
by
fast
enantio-determining
nucleophilic
addition.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(23), P. 8552 - 8558
Published: May 13, 2021
The
three-dimensional
inorganic
analogues
of
9,10-diboraanthracene,
B2X2(C2B10H10)2
(X
=
Cl,
1;
X
Br,
2),
were
attained
by
salt
elimination
Li2C2B10H10
and
trihaloboranes.
methyl-
phenyl-substituted
compounds
B2Me2(C2B10H10)2
(3)
B2Ph2(C2B10H10)2
(4)
obtained
treating
1
or
2
with
the
corresponding
Grignard
reagents.
These
fully
characterized
NMR,
cyclic
voltammetry
(CV),
IR,
single-crystal
X-ray
diffraction
analyses.
Experimental
(CV
Gutmann–Beckett
method)
computational
(fluoride
ion
affinity,
hydride
affinity
LUMO
energy)
results
suggest
that
order
Lewis
acidity
is
>
4
3
SbF5.
Treatment
HSiEt3
gave
a
rare
neutral
borane–silane
adduct,
(Et3SiH)2B2H2(C2B10H10)2
(5).
equilibrium
5
in
solution
was
thoroughly
investigated
spectroscopy
quantum
calculations.
Organic Letters,
Journal Year:
2021,
Volume and Issue:
23(21), P. 8622 - 8627
Published: Oct. 18, 2021
Mechanochemistry
was
successfully
applied
to
the
functionalization
of
carboranes.
The
mechanochemical
iridium(III)-catalyzed
regioselective
B(3)-
and
B(4)-amidation
unsubstituted
o-carboranes
with
dioxazolones
developed.
In
addition,
substituted
demonstrated.
Because
B-amidation
proceeds
smoothly
without
organic
solvents
or
external
heating,
present
method
is
regarded
as
a
sustainable
environmentally
friendly
surrogate
for
typical
solvent-based
reactions.
Inorganic Chemistry,
Journal Year:
2022,
Volume and Issue:
61(13), P. 5326 - 5334
Published: March 21, 2022
The
B(9)-H
halogenation
of
o-carborane
and
m-carborane
was
achieved
with
excellent
selectivities
in
hexafluoroisopropanol
(HFIP)
under
simple
reaction
conditions:
single
reagent
[trichloroisocyanuric
acid
(TCCA),
tribromoisocyanuric
(TBCA)
or
N-iodosuccinimide
(NIS)],
catalyst-free,
air-/moisture-tolerant,
convenient
work-up.
With
this
method,
a
variety
9-halogenated
o-carboranes
m-carboranes
were
obtained
good
to
yields
broad
tolerance
functional
groups.
Organic Letters,
Journal Year:
2022,
Volume and Issue:
24(6), P. 1318 - 1322
Published: Feb. 7, 2022
A
highly
efficient
Ir-catalyzed
regioselective
cage
B(4)-H
acylmethylation
of
o-carboranyl
acids
using
sulfoxonium
ylides
as
alkylating
regents
has
been
developed,
leading
to
the
preparation
a
large
class
B(4)-acylmethylated
o-carboranes
in
good
excellent
yields
with
broad
substrate
scope
under
redox
neutral
conditions.
The
-COOH
moiety
serves
traceless
directing
group
and
controls
regioselectivity
monoselectivity.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(37)
Published: June 7, 2022
Functionalization
of
carboranes
in
a
vertex-specific
manner
is
perennial
challenge.
Here,
we
report
photocatalytic
B-C
coupling
for
the
selective
functionalization
at
boron
site
which
most
distal
to
carbon.
This
reaction
was
achieved
by
photo-induced
decarboxylation
carborane
carboxylic
acids
generate
vertex-centered
carboranyl
radicals.
Theoretical
calculations
also
demonstrate
that
more
easily
occurs
bearing
higher
electron
density
owing
lower
energy
barrier
single-electron
transfer
radical.
By
using
this
strategy,
number
functionalized
could
be
accessed
through
alkylation,
alkenylation,
and
heteroarylation
under
mild
conditions.
Moreover,
both
highly
efficient
blue
emitter
with
solid-state
luminous
efficiency
42
%
drug
candidate
neutron
capture
therapy
(BNCT)
containing
targeting
fluorine
units
were
obtained.
Organometallics,
Journal Year:
2022,
Volume and Issue:
41(12), P. 1480 - 1487
Published: June 2, 2022
Activation
of
atmospherically
abundant
dinitrogen
(N2)
under
mild
conditions
has
been
a
great
challenge
in
chemistry
for
decades
because
the
significantly
strong
N≡N
triple
bond.
The
traditional
strategy
N2
activation
was
mainly
limited
to
metallic
species
until
ground-breaking
achievement
by
two-coordinated
borylenes
achieved
experimentally
2018.
On
other
hand,
carborane
derivatives
have
attracted
considerable
interest
small-molecule
activation.
Still,
utilization
remains
elusive.
Here,
we
design
four
types
carborane-based
frustrated
Lewis
pairs
(FLPs)
probe
their
potential
systematical
density
functional
theory
calculations.
Interestingly,
all
these
FLPs
are
found
become
favorable
both
kinetically
and
thermodynamically
activating
with
low
reaction
barriers
(ranging
from
13.0
25.8
kcal
mol–1)
high
exothermicity,
ΔG
values
ranging
−37.5
−51.0
mol–1,
indicating
metal-free
conditions.
Our
study
opens
an
avenue
activation,
highlighting
importance
field
Advanced Synthesis & Catalysis,
Journal Year:
2022,
Volume and Issue:
364(24), P. 4174 - 4188
Published: Dec. 1, 2022
Abstract
Carboranes,
a
three‐dimensional
class
of
carbon‐boron
molecular
clusters
with
remarkable
electronic,
physical,
chemical
characteristics,
have
proved
as
useful
building
blocks
in
boron
neutron
capture
therapy
agents,
supramolecular
design,
optoelectronics,
nanomaterials
and
organometallic/coordination
chemistry.
Thus,
various
organic
modifications
the
B−H
C−H
functionalities
carboranes
been
developed.
These
methods
great
success
utilize
directing
groups,
such
carboxylic
acids,
to
achieve
selective
functionalization
carboranes.
The
carboxyl
group
can
be
easily
introduced
then
removed
after
reactions.
On
other
hand,
assisted
by
highly
regioselective
electrophilic
attack
at
electron‐rich
positions
B(4)
B(5)
cage
generates
five‐membered
metallacyclic
intermediates,
which
undergo
further
transformation.
In
this
review,
we
show
that
transition
metal‐catalyzed
decarboxylation
cross
coupling
reactions
offer
an
opportunity
for
direct
activation
magnified
image