This
study
investigated
the
catalytic
activities
of
two
Ru
complexes
with
bifunctional
metal-ligand
cooperativity,
named
1b
(containing
a
2-hydroxypyridyl
fragment
and
protic
NHC)
2b
(only
containing
NHC),
for
C-C
bond
formation
through
borrowing
hydrogen
process.
Surprisingly,
complex
2b,
which
lacks
fragment,
exhibited
comparable
activity
to
same
catalyst
loading
in
coupling
broad
range
primary
secondary
alcohols.
The
efficiency
this
straightforward
system
was
further
demonstrated
challenging
reaction
β-alkylation
1-phenylethanol
benzyl
alcohol,
minimal
0.0001
mol%.
highest
TOF
observed
cross-coupling
alcohols
13333
h-1.
Additionally,
found
be
effective
catalysing
aliphatic
double
C-alkylation
cyclopentanol.
finding
holds
promise
development
more
catalysts
reactions
Chemistry - A European Journal,
Год журнала:
2023,
Номер
30(1)
Опубликована: Окт. 9, 2023
Abstract
In
the
present
work,
several
manganese(I)
complexes
of
chelating
heteroditopic
ligands
Mn1–3
,
featuring
ImNHC
(imidazol‐2‐ylidene)
connected
to
a
1,2,3‐triazole‐N
or
tzNHC
(1,2,3‐triazol‐5‐ylidene)
donors
via
methylene
spacer,
with
possible
modifications
at
triazole
backbone
have
been
synthesized
and
completely
characterized.
Notably,
CO
stretching
frequencies,
electrochemical
analysis,
frontier
orbital
analysis
certainly
suggest
that
ImNHC‐tzNHC
stronger
donation
capabilities
than
related
ImNHC‐Ntz
ligand
in
complexes.
Moreover,
these
well‐defined
phosphine‐free
Mn(I)−NHC
found
be
effective
non‐bifunctional
catalysts
for
α‐alkylation
nitriles
using
alcohols
importantly,
catalyst
Mn1
containing
weaker
triazole‐N
donor
displayed
higher
activity
compared
Mn2
/
Mn3
an
unsymmetrical
bis‐carbene
(ImNHC
tzNHC).
A
wide
range
aryl
were
coupled
diverse
(hetero)aromatic
as
well
aliphatic
get
corresponding
products
good
excellent
yields
(32
examples,
up
95
%
yield).
The
detailed
mechanistic
studies
including
deuterium
labelling
experiments
reveal
reaction
follows
Borrowing
Hydrogen
pathway.
Catalysis Science & Technology,
Год журнала:
2022,
Номер
12(12), С. 4050 - 4056
Опубликована: Янв. 1, 2022
A
heteroditopic
Ru(
ii
)-bis-NHC
complex
in
combination
with
dppe
was
developed
as
an
effective
catalyst
system
(0.2
mol%
loading)
for
the
N
-alkylation
of
amides
and
selective
mono-/di-alkylation
4-aminobenzamide
derivatives
excellent
yields.
This
study
investigated
the
catalytic
activities
of
two
Ru
complexes
with
bifunctional
metal-ligand
cooperativity,
named
1b
(containing
a
2-hydroxypyridyl
fragment
and
protic
NHC)
2b
(only
containing
NHC),
for
C-C
bond
formation
through
borrowing
hydrogen
process.
Surprisingly,
complex
2b,
which
lacks
fragment,
exhibited
comparable
activity
to
same
catalyst
loading
in
coupling
broad
range
primary
secondary
alcohols.
The
efficiency
this
straightforward
system
was
further
demonstrated
challenging
reaction
β-alkylation
1-phenylethanol
benzyl
alcohol,
minimal
0.0001
mol%.
highest
TOF
observed
cross-coupling
alcohols
13333
h-1.
Additionally,
found
be
effective
catalysing
aliphatic
double
C-alkylation
cyclopentanol.
finding
holds
promise
development
more
catalysts
reactions
