The Journal of Physical Chemistry A,
Год журнала:
2019,
Номер
123(47), С. 10263 - 10272
Опубликована: Окт. 30, 2019
The
ruthenium(II)-catalyzed
α-alkylation
reaction
of
arylmethyl
nitriles
(phenylacetonitrile)
using
alcohols
(ethanol)
in
toluene
has
been
extensively
investigated
by
means
SMD-M06-2X/6-311G(d,p)-LANL2dz
(LAnL2dz
for
Ru,
6-311G(d,p)
other
atoms)
calculations.
Detailed
mechanistic
schemes
have
proposed
and
discussed.
catalytically
active
Ru(II)
complex
was
generated
the
base-induced
KCl
elimination
from
catalyst
precursor
[(PNPPh)RuHCl(CO)].
overall
catalytic
cycle
consists
three
basic
processes:
(1)
ethanol-to-aldehyde
transformation
catalyzed
16-electron
unsaturated
ruthenium
pincer
catalyst;
(2)
a
condensation
nitrile
with
aldehyde,
which
leads
to
PhC(CN)=CHCH3;
(3)
hydrogenation
PhC(CN)=CHCH3,
formation
α-alkylated
product
(PhCH(CH2CH3)CN).
DFT
results
revealed
that
rate-determining
barrier
23.9
kcal/mol
H-transfer
step
third
process.
PhC(CN)=CHCH3
dihydride
Ru
complex,
is
process,
more
preferable
mechanism
than
vinyl
nitrile-Ru
H2.
Using
alcohol
as
reactant
not
only
fulfills
requirement
borrowing-H
strategy
but
also
lowers
barriers
H-migration
steps.
Organometallics,
Год журнала:
2019,
Номер
38(19), С. 3590 - 3601
Опубликована: Сен. 30, 2019
A
density
functional
theory
(DFT)
study
has
been
carried
out
to
gain
insight
into
the
acceptorless
dehydrogenative
coupling
(ADC)
reactions
of
primary
alcohols
with
hydrazine
afford
alkene
or
azine,
catalyzed
by
PNP-Mn
pincer
catalyst.
The
reaction
takes
place
via
three
stages:
alcohol
dehydrogenation
give
aldehyde
(stage
1),
hydrazone
2),
and
further
azine
3).
Stage
2
is
rate-determining
step
a
barrier
31.7
kcal/mol,
while
stage
3
determines
chemoselectivity.
In
3,
N–H
addition
gives
nucleophilic
[Mn]–N1H–N2═C1HR
intermediate
(i.e.,
IM7
IM7a)
featuring
two
sites
at
N1
C1.
attack
C1
leads
alkene,
azine.
kinetic
competition
between
pathways
controls
chemoselectivity
reaction.
If
aromatic
such
as
benzyl
alcohol,
then
pathway
initiated
kinetically
more
favorable,
leading
alkene.
For
aliphatic
wins,
resulting
in
N2
extrusion
involved
formation
dissociation
an
anionic
species
CHR–C(OH)HR,
8–/8a–)
from
resulted
C,C
coupling.
hydrazine,
originates
electron-withdrawing
effect
group
on
fragment,
which
lowers
for
dissociation.
We
expect
these
in-depth
mechanistic
insights
provide
valuable
guidance
understanding
help
develop
new
ADC
reactions.
Organometallics,
Год журнала:
2023,
Номер
42(13), С. 1615 - 1620
Опубликована: Июнь 3, 2023
Enyne
metathesis
reactions
involving
metallacyclobutene
intermediates
have
been
comprehensively
studied
and
utilized
in
numerous
synthetic
processes
catalytic
transformations.
We
describe
here
our
initial
results
toward
the
utilization
of
metalla-aromatic
classical
[2
+
2]
cycloaddition
that
η3-allyl
structures
are
formed
stoichiometrically
through
hydrogen-bonding-induced
between
several
propynol
a
ruthenabenzene
complex.
The
effect
intramolecular
hydrogen
bonding
interaction
was
analyzed
by
experimental
computational
studies.
Frontiers in Chemistry,
Год журнала:
2020,
Номер
8
Опубликована: Сен. 16, 2020
A
mild
ruthenium(II)-catalyzed
homocoupling
of
α-carbonyl
sulfoxonium
ylides
was
developed
and
the
detailed
mechanism
understood
based
on
DFT
calculations
in
current
report.
The
catalytic
system
utilizes
ylide
as
both
directing
group
for
ortho-2
sp
2
C-H
activation
acylmethylating
regent
C-C
coupling.
Various
substituents
are
compatible
transformation
a
variety
isocoumarin
derivatives
were
synthesized
at
room
temperature
without
any
protection.
theoretical
results
disclosed
that
full
cycle
contain
eight
elementary
steps,
all
which
cationic
Ru(II)
monomer
is
involved
active
species.
acid
additive
responsible
protonation
carbon
prior
to
intramolecular
nucleophilic
addition
bond
cleavage.
Interestingly,
intermediacy
free
acylmethylation
intermediate
or
its
enol
isomer
not
necessary
transformation.
The Journal of Physical Chemistry A,
Год журнала:
2019,
Номер
123(47), С. 10263 - 10272
Опубликована: Окт. 30, 2019
The
ruthenium(II)-catalyzed
α-alkylation
reaction
of
arylmethyl
nitriles
(phenylacetonitrile)
using
alcohols
(ethanol)
in
toluene
has
been
extensively
investigated
by
means
SMD-M06-2X/6-311G(d,p)-LANL2dz
(LAnL2dz
for
Ru,
6-311G(d,p)
other
atoms)
calculations.
Detailed
mechanistic
schemes
have
proposed
and
discussed.
catalytically
active
Ru(II)
complex
was
generated
the
base-induced
KCl
elimination
from
catalyst
precursor
[(PNPPh)RuHCl(CO)].
overall
catalytic
cycle
consists
three
basic
processes:
(1)
ethanol-to-aldehyde
transformation
catalyzed
16-electron
unsaturated
ruthenium
pincer
catalyst;
(2)
a
condensation
nitrile
with
aldehyde,
which
leads
to
PhC(CN)=CHCH3;
(3)
hydrogenation
PhC(CN)=CHCH3,
formation
α-alkylated
product
(PhCH(CH2CH3)CN).
DFT
results
revealed
that
rate-determining
barrier
23.9
kcal/mol
H-transfer
step
third
process.
PhC(CN)=CHCH3
dihydride
Ru
complex,
is
process,
more
preferable
mechanism
than
vinyl
nitrile-Ru
H2.
Using
alcohol
as
reactant
not
only
fulfills
requirement
borrowing-H
strategy
but
also
lowers
barriers
H-migration
steps.
