ACS Catalysis,
Год журнала:
2023,
Номер
13(9), С. 5949 - 5954
Опубликована: Апрель 17, 2023
Sulfones
are
building
blocks
in
organic
synthesis
and
pharmaceutical
chemistry.
Direct
α-alkylation
of
sulfones
using
alcohols
with
water
as
the
sole
byproduct
is
an
efficient
promising
method
for
their
structural
modifications.
However,
competitive
reactions
always
exist
this
transformation
that
influences
reaction
selectivity.
For
example,
addition
to
desired
α-alkylation,
Julia-type
olefination
α-alkenylation
frequently
observed,
especially
when
benzyl
alcohol
derivatives
were
used
alkylation
reagents.
Herein,
we
report
catalyzed
by
a
pincer
complex
earth-abundant
manganese.
The
Mn-PNN-bipyridyl
exhibited
good
performance
amount
base
also
had
important
influence
on
smooth
transformation.
Aromatic
aliphatic
suitable
reagents
at
low
metal
catalyst
loading
(0.5
mol
%),
highlighting
practicality
developed
system.
Organometallics,
Год журнала:
2023,
Номер
42(14), С. 1818 - 1831
Опубликована: Июнь 24, 2023
A
series
of
manganese
carbonyl
complexes
based
on
bis(imino)pyridine
ligands
the
type
R2NNN
(R
=
Cy,
iPr,
Ph,
p-FC6H4)
were
synthesized.
While
complex
appears
to
be
an
NN
bidentate-Mn(I)
triscarbonyl
species
in
solid
state,
solution,
there
is
a
gradual
loss
carbon
monoxide
leading
first
NNN
pincer-Mn(I)
biscarbonyl
complex,
which
finally
disproportionates
pincer-Mn(II)
dibromide
and
pincer-Mn(0)
complex.
Evidence
for
this
transformation
has
been
obtained
from
single-crystal
X-ray
diffraction,
IR,
EPR,
HRMS
analysis.
The
apparently
faster
with
cyclohexyl-substituted
than
others.
considered
(0.05
mol
%)
utilized
catalyzing
β-alkylation
secondary
alcohols
at
140
°C
air
under
conventional
heating
(12
h),
as
well
microwave
(2
h)
presence
2.5
%
NaOtBu.
Among
complexes,
catalyst
(p-FC6H4NNN)Mn(CO)2Br
was
found
highly
efficient.
heating,
maximum
92%
(1840
TON
153
TOs/h)
β-alkylated
product
obtained;
provided
85%
yield
(1700
850
just
2
h.
catalytic
system
successfully
implemented
alkylate
several
other
alcohols,
(35
examples).
analyses
indicate
intermediates
cycle
both
pincer-Mn(II)/Mn(0)
couple.
Deuterium
labeling
studies
point
involvement
C–H
bond
activation
rate-determining
step
(RDS)
kinetic
isotope
effect
(KIE)
9.0.
ChemSusChem,
Год журнала:
2020,
Номер
14(3), С. 860 - 865
Опубликована: Дек. 22, 2020
Abstract
The
implementation
of
non‐noble
metals
mediated
chemistry
is
a
major
goal
in
homogeneous
catalysis.
Borrowing
hydrogen/hydrogen
autotransfer
(BH/HA)
reaction,
as
straightforward
and
sustainable
synthetic
method,
has
attracted
considerable
attention
the
development
metal
catalysts.
Herein,
we
report
tungsten‐catalyzed
N
‐alkylation
reaction
anilines
with
primary
alcohols
via
BH/HA.
This
phosphine‐free
W(phen)(CO)
4
(phen=1,10‐phenthroline)
system
was
demonstrated
practical
easily
accessible
in‐situ
catalysis
for
broad
range
amines
(up
to
49
examples,
including
16
previously
undisclosed
products).
Notably,
this
tungsten
can
tolerate
numerous
functional
groups,
especially
challenging
substrates
sterically
hindered
substituents,
or
heteroatoms.
Mechanistic
insights
based
on
experimental
computational
studies
are
also
provided.
ACS Catalysis,
Год журнала:
2021,
Номер
11(17), С. 10796 - 10801
Опубликована: Авг. 16, 2021
The
direct
conversion
of
alcohols
into
long-chain
alkanes
is
an
attractive
but
extremely
challenging
approach
for
biomass
upgrading.
Here,
we
describe
the
highly
selective
deoxygenative
coupling
aryl
ethanols
with
primary
to
produce
alkanes,
using
a
bis-N-heterocyclic
carbene
iridium
(bis-NHC-Ir)
complex
as
catalyst.
Up
quantitative
yields
and
selectivity
broad
substrate
scope
are
attained
in
both
homo-
cross-coupling
reactions.
Mechanistic
studies
reveal
that
further
synergistic
hydrogenation
alkene
intermediates
by
formate
generated
situ
presence
bis-NHC-Ir
crucial
alkane
production.
New Journal of Chemistry,
Год журнала:
2021,
Номер
45(22), С. 10057 - 10062
Опубликована: Янв. 1, 2021
An
efficient
Ni-catalyzed
C3-alkylation
of
indoles
with
alcohols
via
a
borrowing
hydrogen
pathway
was
achieved
utilizing
an
N,O-donor
coordinated
nickel
complex
as
the
precatalyst.
ACS Catalysis,
Год журнала:
2023,
Номер
13(9), С. 5949 - 5954
Опубликована: Апрель 17, 2023
Sulfones
are
building
blocks
in
organic
synthesis
and
pharmaceutical
chemistry.
Direct
α-alkylation
of
sulfones
using
alcohols
with
water
as
the
sole
byproduct
is
an
efficient
promising
method
for
their
structural
modifications.
However,
competitive
reactions
always
exist
this
transformation
that
influences
reaction
selectivity.
For
example,
addition
to
desired
α-alkylation,
Julia-type
olefination
α-alkenylation
frequently
observed,
especially
when
benzyl
alcohol
derivatives
were
used
alkylation
reagents.
Herein,
we
report
catalyzed
by
a
pincer
complex
earth-abundant
manganese.
The
Mn-PNN-bipyridyl
exhibited
good
performance
amount
base
also
had
important
influence
on
smooth
transformation.
Aromatic
aliphatic
suitable
reagents
at
low
metal
catalyst
loading
(0.5
mol
%),
highlighting
practicality
developed
system.
