Inorganic Chemistry,
Journal Year:
2021,
Volume and Issue:
60(15), P. 10958 - 10969
Published: July 16, 2021
The
mechanism
of
the
aluminum-mediated
hydroboration
terminal
alkynes
was
investigated
using
a
series
novel
aluminum
amidinate
hydride
and
alkyl
complexes
bearing
symmetric
asymmetric
ligands.
new
were
fully
characterized
found
to
facilitate
formation
(E)-vinylboronate
product,
with
rates
orders
reaction
linked
complex
size
stability.
Kinetic
analysis
stoichiometric
reactions
used
elucidate
mechanism,
which
we
propose
proceed
via
initial
an
Al-borane
adduct.
Additionally,
most
unstable
promote
decomposition
pinacolborane
substrate
borane
(BH3),
can
then
catalyze
reaction.
This
is
in
contrast
previously
reported
hydride-catalyzed
reactions,
are
proposed
acetylide,
or
by
hydroalumination
form
vinylboronate
ester
as
first
step
catalytic
cycle.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(5), P. 3065 - 3073
Published: Feb. 13, 2024
Facile
synthesis
of
vinyl
boronate
esters
via
dehydrogenative
borylation
terminal
alkenes
was
accomplished
by
employing
a
recyclable
cobalt-metal–organic
framework
(MOF)
catalyst
and
dimethylformamide
(DMF)
solvent
as
hydrogen
scavenger.
This
process
avoids
using
special
ligands,
high
temperatures,
long
reaction
time,
additional
acceptors
can
be
carried
out
in
air.
A
wide
range
mono-
disubstituted
aromatic
alkenes,
along
with
aliphatic
were
well
tolerated
under
mild
conditions.
The
synthetic
importance
demonstrated
installing
various
functionalities
into
the
vinylic
C–B
bond.
Importantly,
could
reused
up
to
5
times
without
significant
loss
activity.
proposed
catalytic
cycle
has
been
evaluated
based
on
stoichiometric
reactions
density
functional
theory
(DFT)
calculations.
The Journal of Organic Chemistry,
Journal Year:
2021,
Volume and Issue:
86(13), P. 9117 - 9133
Published: June 17, 2021
Hydroboration
reaction
of
alkynes
is
one
the
most
synthetically
powerful
tools
to
access
organoboron
compounds,
versatile
precursors
for
cross-coupling
chemistry.
This
type
has
traditionally
been
mediated
by
transition-metal
or
main
group
catalysts.
Herein,
we
report
a
novel
method
using
tropylium
salts,
typically
known
as
organic
oxidants
and
Lewis
acids,
promote
hydroboration
alkynes.
A
broad
range
vinylboranes
can
be
easily
accessed
via
this
metal-free
protocol.
Similar
reactions
alkenes
epoxides
also
efficiently
catalyzed
same
Experimental
studies
DFT
calculations
suggested
that
follows
an
uncommon
mechanistic
pathway,
which
triggered
hydride
abstraction
pinacolborane
with
ion.
followed
series
in
situ
counterion-activated
substituent
exchanges
generate
boron
intermediates
reaction.
Chemistry - A European Journal,
Journal Year:
2021,
Volume and Issue:
27(51), P. 13072 - 13078
Published: June 25, 2021
Bis-NHC
stabilized
germyliumylidenes
[RGe(NHC)2
]+
are
typically
Lewis
basic
(LB)
in
nature,
owing
to
their
lone
pair
and
coordination
of
two
NHCs
the
vacant
p-orbitals
germanium
center.
However,
they
can
also
show
acidity
(LA)
via
Ge-CNHC
σ*
orbital.
Utilizing
this
unique
electronic
feature,
we
report
first
example
bis-NHC-stabilized
germyliumylidene
[Mes
TerGe(NHC)2
]Cl
(1),
(Mes
Ter=2,6-(2,4,6-Me3
C6
H2
)2
H3
;
NHC=
IMe4
=1,3,4,5-tetramethylimidazol-2-ylidene)
catalyzed
reduction
CO2
with
amines
arylsilane,
which
proceeds
its
nature.
In
contrast,
acid
nature
1
is
utilized
hydroboration
cyanosilylation
carbonyls,
thus
highlighting
versatile
ambiphilic
bis-NHC
germyliumylidenes.
Dalton Transactions,
Journal Year:
2021,
Volume and Issue:
50(7), P. 2354 - 2358
Published: Jan. 1, 2021
A
very
simple
and
readily
accessible
lithium
compound
has
been
employed
to
catalyze
the
hydroboration
of
tertiary,
secondary,
primary
amides
corresponding
amines.
Chemistry - A European Journal,
Journal Year:
2023,
Volume and Issue:
29(38)
Published: April 20, 2023
A
fluorenyl-tethered
N-heterocyclic
carbene
LH
(LH=[(Flu)H-(CH2
)2
-NHCDipp
])
and
its
monoanionic
version
L-
are
explored
in
complexation
with
zinc
towards
the
hydroboration
of
N-heteroarenes,
carbonyl,
ester,
amide,
nitrile
under
ambient
condition.
The
N-heteroarenes
exhibit
high
1,2-regioselectivity
which
is
justified
by
computational
analyses.
relative
rates
differently
p-substituted
(electron
donating
vs.
withdrawing)
pyridines
also
addressed.
monodentate
offers
a
better
catalytic
activity
than
chelating
for
steric
reasons
despite
both
giving
three-coordinate
complexes.
mechanism
involves
Zn-H
species
at
heart
these
processes
trapped
Ph2
CO.
Computational
studies
suggest
that
barrier
to
form
hydride
complex
comparable
required
following
transfer
pyridine.
ChemCatChem,
Journal Year:
2022,
Volume and Issue:
15(2)
Published: Nov. 24, 2022
Abstract
This
review
discusses
the
immense
progress
made
over
recent
years
in
metal‐free
catalytic
hydroboration.
Reactions
with
several
unsaturated
functional
groups,
such
as
alkynes,
alkenes,
carbonyl
compounds,
carbon
dioxide,
carbodiimides,
imines,
allenes,
pyridines,
carboxylic
acid
derivatives
etc.,
have
been
explored.
Although
there
are
significant
developments
hydroboration
reactions
using
metal‐based
catalysts,
strategies
more
desirable
from
a
sustainability
perspective.
Considerable
effort
has
by
various
research
groups
on
catalysts
of
compounds.
Lewis
acid,
Brønsted
acid‐base
pairs,
and
frustrated
pairs
were
involved
sources
to
catalyze
sustainable
manner.
Detailed
mechanisms
pathways
also
discussed
this
review.
discussion
will
provide
an
overview
extent
work
carried
out
well
indicate
scope
for
future
research.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
62(2)
Published: Nov. 15, 2022
Building
up
new
and
efficient
methods
for
the
controlled
conversion
of
carboxylic
acids
to
aldehydes
is
important.
Herein,
we
report
a
rapid,
modular
scalable
method
using
pinacolborane
at
ambient
temperature,
in
which
triflylpyridinium
reagent
used.
The
acid
intermediate
acylpyridinium
by
new.
A
binary
pyridine-coordinated
boronium
complex
generated
after
reduction.
unprecedented
reduction
HBpin
opens
practically
direct
synthesis
from
acids.
Theoretical
studies
indicate
that
requires
lower
activation
free
energy
than
product
aldehyde.
synthetic
advantage
this
protocol
further
highlighted
aldehyde
via
continuous
flow
process.
Configuration
retention
chiral
are
presented
those
syntheses.
Chemistry - A European Journal,
Journal Year:
2022,
Volume and Issue:
28(63)
Published: Aug. 2, 2022
We
report
a
transition
metal-free,
regio-
and
stereo-selective,
phosphine-catalyzed
method
for
the
trans
hydroboration
of
1,3-diynes
with
pinacolborane
that
affords
(E)-1-boryl-1,3-enynes.
The
reaction
proceeds
excellent
selectivity
boron
addition
to
external
carbon
1,3-diyne
framework
as
unambiguously
established
by
NMR
X-ray
crystallographic
studies.
displays
broad
substrate
scope
including
unsymmetrical
diynes
generate
products
in
high
yield
(up
95
%).
Experimental
theoretical
studies
suggest
phosphine
attack
on
alkyne
is
key
process
catalytic
cycle.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(17)
Published: Feb. 23, 2023
1,3,2-diazaphospholene
hydrides
(DAP-H)
enable
smooth
conjugate
reduction
of
polarized
double
bonds.
The
transiently
formed
phosphorus-enolate
provides
a
potential
platform
for
reductive
α-functionalizations.
In
this
respect,
asymmetric
C-heteroatom
bond
forming
processes
are
synthetically
appealing
but
remain
elusive.
We
report
1,3,2-diazaphospholene-catalyzed
three-step
cascade
reaction
N-sulfinyl
acrylamides
comprised
reduction,
[2,3]-sigmatropic
aza-Mislow-Evans
rearrangement
and
subsequent
S-O
cleavage.
obtained
enantio-enriched
α-hydroxy
amides
in
good
yields
excellent
enantiospecificity.
stereo-defined
P-bound
N,O-ketene
aminal
ensures
an
transfer
chirality
from
the
sulfur
stereocenter
to
α-carbon.
transformation
operates
under
mild
conditions
at
ambient
temperature.
Moreover,
DAP-H
is
competent
reductant
cleavage
sulfenate
ester,
eliminating
extra
step
traditional
Mislow-Evans
processes.
