Chemistry - A European Journal,
Год журнала:
2023,
Номер
29(58)
Опубликована: Июль 19, 2023
In
recent
years,
there
has
been
a
concerted
drive
to
develop
methods
that
are
greener
and
more
sustainable.
Being
an
earth-abundant
transition
metal,
cobalt
offers
attractive
substitute
for
commonly
employed
precious
metal
catalysts,
though
reactions
engaging
still
less
developed.
Herein,
we
report
method
achieve
the
decarboxylative
allylation
of
nitrophenyl
alkanes,
nitroalkanes,
ketones
employing
cobalt.
The
reaction
allows
formation
various
substituted
allylated
products
in
moderate-excellent
yields
with
broad
scope.
Additionally,
synthetic
potential
methodology
is
demonstrated
by
transformation
into
versatile
heterocyclic
motifs.
Mechanistic
studies
revealed
situ
activation
Co(II)/dppBz
precatalyst
carboxylate
salt
generate
Co(I)-species,
which
presumed
be
active
catalyst.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
10(12), С. 2976 - 2987
Опубликована: Янв. 1, 2023
DFT
calculations
reveal
an
inner-sphere
C–N
reductive
elimination
pathway
for
the
cobalt/bisoxazolinephosphine-catalyzed
allylic
substitution
of
racemic
carbonates
with
amines.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(46)
Опубликована: Сен. 29, 2023
Abstract
Here,
we
report
the
development
of
cobalt(I)‐catalyzed
regioselective
allylic
alkylation
reactions
tertiary
allyl
carbonates
with
1,3‐dicarbonyl
compounds.
A
family
well‐defined
tetrahedral
cobalt(I)
complexes
bearing
commercially
available
bidentate
bis(phosphine)
ligands
[(P,P)Co(PPh
3
)Cl]
are
synthesized
and
explored
as
catalysts
in
reactions.
The
catalyst
[(dppp)Co(PPh
(dppp=1,3‐Bis(diphenylphosphino)propane)
enables
a
large
variety
high
yields
excellent
regioselectivity
for
branched
product.
Remarkably,
this
methodology
is
selective
activation
even
presence
secondary
carbonates.
This
contrasts
selectivity
observed
cobalt‐catalyzed
alkylations
enabled
by
visible
light
photocatalysis.
Mechanistic
insights
means
experimental
computational
investigations
support
Co(I)/Co(III)
catalytic
cycle.
Angewandte Chemie,
Год журнала:
2024,
Номер
136(7)
Опубликована: Янв. 2, 2024
Abstract
Chromium‐catalyzed
enantioselective
Nozaki–Hiyama–Kishi
(NHK)
reaction
represents
one
of
the
most
powerful
approaches
for
formation
chiral
carbon‐heteroatom
bond.
However,
construction
sterically
encumbered
tetrasubstituted
stereocenter
through
NHK
still
posts
a
significant
challenge.
Herein,
we
disclose
cobalt‐catalyzed
aza‐NHK
ketimine
with
alkenyl
halide
to
provide
convenient
synthetic
approach
manufacture
enantioenriched
α‐vinylic
amino
acid.
This
protocol
exhibits
excellent
functional
group
tolerance
99
%
ee
in
cases.
Additionally,
this
asymmetric
reductive
method
is
also
applicable
aldimine
access
trisubstituted
stereogenic
centers.
Chemistry - A European Journal,
Год журнала:
2023,
Номер
29(58)
Опубликована: Июль 19, 2023
In
recent
years,
there
has
been
a
concerted
drive
to
develop
methods
that
are
greener
and
more
sustainable.
Being
an
earth-abundant
transition
metal,
cobalt
offers
attractive
substitute
for
commonly
employed
precious
metal
catalysts,
though
reactions
engaging
still
less
developed.
Herein,
we
report
method
achieve
the
decarboxylative
allylation
of
nitrophenyl
alkanes,
nitroalkanes,
ketones
employing
cobalt.
The
reaction
allows
formation
various
substituted
allylated
products
in
moderate-excellent
yields
with
broad
scope.
Additionally,
synthetic
potential
methodology
is
demonstrated
by
transformation
into
versatile
heterocyclic
motifs.
Mechanistic
studies
revealed
situ
activation
Co(II)/dppBz
precatalyst
carboxylate
salt
generate
Co(I)-species,
which
presumed
be
active
catalyst.
