Controlling hydrogen transfer dynamics in adaptive semihydrogenation of alkynes: Unveiling and directing outer- vs. inner-sphere mechanisms
Chem Catalysis,
Год журнала:
2024,
Номер
4(9), С. 101078 - 101078
Опубликована: Авг. 20, 2024
Язык: Английский
Zinc-Catalyzed Hydroboration of Carbon Dioxide Amplified by Borane-Tethered Heteroscorpionate Bis(Pyrazolyl)methane Ligands
Inorganic Chemistry,
Год журнала:
2024,
Номер
63(18), С. 8244 - 8256
Опубликована: Апрель 24, 2024
The
borane-functionalized
(BR2)
bis(3,5-dimethylpyrazolyl)methane
(LH)
ligands
1a
(BR2:
9-borabicyclo[3.3.1]nonane
or
9-BBN),
1b
BCy2),
and
1c
B(C6F5)2)
were
synthesized
by
the
allylation–hydroboration
of
LH.
Metalation
1a,b
with
ZnCl2
yielded
heteroscorpionate
dichloride
complexes
[(1a,b)ZnCl2]
3a,b.
reaction
ZnEt2
led
to
formation
zwitterionic
complex
[Et(1a)ZnEt(THF)]
5.
3a
two
equivalents
KHBEt3
under
a
carbon
dioxide
(CO2)
atmosphere
gave
rise
dimeric
bis(formate)
[(1a)Zn(OCHO)2]2
8,
in
which
its
borane
moieties
intermolecularly
stabilize
formate
opposite
metal
centers.
allylated
precursor
Lallyl
zinc
dichloride,
diethyl
[(Lallyl)ZnCl2]
2,
[(Lallyl)ZnEt2]
4,
[(Lallyl)Zn(OCHO)2]
7
also
isolated.
catalyst
systems
composed
1
mol
%
3b
hydroborated
CO2
at
bar
pinacolborane
(HBPin)
methanol-level
product
H3COBPin
(and
PinBOBPin)
yields
42
86%,
respectively.
using
unfunctionalized
[(LH)ZnCl2]
6
KHBEt3/nOctBR2
9-BBN
BCy2)
but
2.5-
6-fold
lower
activities
than
those
exhibited
3a,b/KHBEt3.
hydroboration
8
as
39–43%,
comparable
obtained
3a/KHBEt3.
results
confirmed
that
catalytic
intermediates
benefit
from
incorporated
boranes'
intra-
intermolecular
stabilizations.
Язык: Английский
1,4-Diphosphorinane Synthesis at a Cationic Aluminum(III) Center
Organometallics,
Год журнала:
2024,
Номер
44(1), С. 148 - 157
Опубликована: Дек. 18, 2024
Lewis
acidic
group
13
cations
are
useful
mediators
of
small-molecule
and
catalytic
reactivity
alike.
Previous
work
has
elaborated
on
the
use
bulky
β-diketiminate
Al(III)
for
cycloaddition
intermolecular
coupling
alkene
substrates,
giving
new
[Al]–C
bonds.
Motivated
by
a
desire
to
prepare
aluminum/phosphorus-containing
ambiphilic
ligands,
here
we
probe
intramolecular
mono-
diphosphines
bearing
pendent
group.
Despite
drive
Al–P
bond
formation
(as
shown
control
experiments),
reaction
specialized
allyl-appended
diphosphine
results
in
rapid
cyclization,
producing
an
aluminum-bound
1,4-diphosphorinane
(six-membered
ring).
Together,
this
contribution
offers
complementary
route
toward
class
molecule
emphasizes
importance
substrate
design
characteristics
such
as
phosphorus/alkene(β-carbon)
linker
length
accessing
productive
cyclization.
The
subsequent
heterocycle,
including
coordination
chemistry
with
gold(I),
additionally
shared.
Язык: Английский
A Catalytic Collaboration: Pairing Transition Metals and Lewis Acids for Applications in Organic Synthesis
Dalton Transactions,
Год журнала:
2024,
Номер
53(32), С. 13298 - 13307
Опубликована: Янв. 1, 2024
The
use
of
metal
catalysts
to
accelerate
an
organic
transformation
has
proven
indispensable
for
access
structural
motifs
having
applications
across
medicinal,
polymer,
materials
chemistry,
and
more.
Most
catalytic
approaches
have
cast
transition
metals
in
the
"leading
role";
these
players
mediate
important
reactions
such
as
C-C
cross
coupling
hydrogenation
unsaturated
bonds.
These
may
require
collaboration,
featuring
Lewis
acidic
or
basic
additives
promote
a
desired
reaction
outcome.
acids
can
serve
by
way
substrate
stabilization
and/or
activation,
such,
are
valuable
optimizing
transformations.
A
burgeoning
area
chemical
research
which
unifies
concepts
thus
sought
develop
complexes
ambiphilic
(containing
unit)
ligands.
This
approach
takes
advantage
metal-ligand
cooperativity
increase
efficiency
given
transformation,
leveraging
intramolecular
interactions
between
adjacent
secondary
ligand
site.
While
this
shown
significant
potential
facilitate
challenging
transformations,
there
remains
unexplored
depth
creativity
future
advancement.
Язык: Английский