Chemistry - A European Journal,
Journal Year:
2023,
Volume and Issue:
29(58)
Published: July 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.
Chemical Reviews,
Journal Year:
2021,
Volume and Issue:
121(8), P. 4373 - 4505
Published: March 19, 2021
This
Review
compiles
the
evolution,
mechanistic
understanding,
and
more
recent
advances
in
enantioselective
Pd-catalyzed
allylic
substitution
decarboxylative
oxidative
substitutions.
For
each
reaction,
catalytic
data,
as
well
examples
of
their
application
to
synthesis
complex
molecules,
are
collected.
Sections
which
we
discuss
key
aspects
for
high
selectivity
a
comparison
with
other
metals
(with
advantages
disadvantages)
also
included.
asymmetric
substitution,
data
grouped
according
type
nucleophile
employed.
Because
prominent
position
use
stabilized
carbon
nucleophiles
heteronucleophiles,
many
chiral
ligands
have
been
developed.
To
better
compare
results,
they
presented
by
ligand
types.
reactions
mainly
promoted
PHOX
or
Trost
ligands,
justifies
organizing
this
section
chronological
order.
results
used.
Chemical Reviews,
Journal Year:
2021,
Volume and Issue:
121(7), P. 4084 - 4099
Published: Feb. 11, 2021
Asymmetric
allylic
alkylation
mediated
by
transition
metals
provides
an
efficient
strategy
to
form
quaternary
stereogenic
centers.
While
this
transformation
is
dominated
the
use
of
second-
and
third-row
(e.g.,
Pd,
Rh,
Ir),
recent
developments
have
revealed
potential
first-row
metals,
which
provide
not
only
a
less
expensive
potentially
equally
alternative
but
also
new
mechanistic
possibilities.
This
review
summarizes
examples
for
assembly
stereocenters
using
prochiral
substrates
hard,
achiral
nucleophiles
in
presence
copper
complexes
highlights
complementary
approaches
with
soft,
catalyzed
chiral
cobalt
nickel
complexes.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(7)
Published: Jan. 2, 2024
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.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(32), P. 12755 - 12765
Published: Aug. 5, 2021
Catalytic
generation
of
ambiphilic
π-allyl–metal
complexes
and
their
utility
in
enantioselective
transformations
constitutes
a
powerful
approach
for
introduction
allyl
groups
to
molecule.
Herein
an
unprecedented
cobalt-catalyzed
highly
site-,
diastereo-,
protocol
stereoselective
formation
nucleophilic
allyl–Co(II)
followed
by
addition
aldehydes
is
presented.
The
reaction
features
diastereo-
enantioconvergent
conversion
easily
accessible
allylic
alcohol
derivatives
diversified
enantioenriched
homoallylic
alcohols
with
remarkably
broad
scope
that
can
be
introduced.
Mechanistic
studies
indicated
radical
intermediates
were
involved
this
process.
These
new
discoveries
establish
strategy
development
through
capture
radicals
chiral
Co
complexes,
pushing
forward
the
frontier
catalysis.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(7), P. 2893 - 2898
Published: Feb. 14, 2022
Transition-metal-catalyzed
branched
and
enantioselective
allylic
substitution
of
monosubstituted
precursors
with
carbon,
nitrogen,
oxygen,
sulfur,
fluoride
nucleophiles
has
been
well-established.
However,
such
a
selective
carbon–phosphorus
bond
formation
not
realized
probably
due
to
the
catalyst
deactivation
by
strong
coordinating
nature
phosphinylating
reagents.
Herein,
we
report
Rh-catalyzed
highly
regio-
synthesis
phosphine
oxides
in
presence
chiral
bisoxazoline-phosphine
ligand.
The
application
α-hydroxylalkylphosphine
keep
low
concentration
secondary
is
essential
for
high
yields.
addition
diphenyl
phosphoric
acid
was
found
only
activate
alcohols
but
also
accelerate
formation.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(50), P. 23001 - 23009
Published: Dec. 8, 2022
A
new
regio-
and
stereoselective
reductive
coupling
of
alkynes
crotononitrile
has
been
developed
via
visible
light
organophotoredox
cobalt
dual
catalysis.
variety
enantioenriched
homoallylic
nitriles
bearing
a
stereodefined
trisubstituted
alkene
have
easily
synthesized
with
good
to
excellent
(up
>20:1
rr),
stereo-
(>20:1
E/Z),
enantioselectivity
98%
ee)
control
under
mild
conditions.
The
corresponding
nitrile
products
were
smoothly
converted
into
various
chiral
building
blocks.
Remarkably,
simple
organic
base
together
water
utilized
as
hydrogen
sources
in
this
photoinduced
reaction.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(7), P. 3897 - 3902
Published: Feb. 8, 2023
Rh/silane-cocatalyzed
regio-
and
enantioselctive
allylic
cyanomethylation
with
inert
acetonitrile
directly
has
been
developed.
Addition
of
a
catalytic
amount
neutral
silane
reagent
as
an
anion
carrier
is
essential
for
the
success
this
reaction.
The
synthesis
mono-
bis-allylation
products
can
be
switched
by
adjusting
size
substituents
on
silane,
ligands,
temperature.
Chiral
homoallylic
nitriles
could
synthesized
in
above
20:1
branch/linear
ratio,
up
to
98%
yield
>99%
ee.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(25)
Published: Jan. 22, 2024
β-Tertiary
amino
acid
derivatives
constitute
one
of
the
most
frequently
occurring
units
in
natural
products
and
bioactive
molecules.
However,
efficient
asymmetric
synthesis
this
motif
still
remains
a
significant
challenge.
Herein,
we
disclose
cobalt-catalyzed
enantioselective
reductive
addition
reaction
ketimine
using
α-chloro
carbonyl
compound
as
radical
precursor,
providing
expedient
access
to
diverse
array
enantioenriched
β-quaternary
analogues.
This
protocol
exhibits
outstanding
enantioselectivity
broad
substrate
scope
with
excellent
functional
group
tolerance.
Preliminary
mechanism
studies
rule
out
possibility
Reformatsky-type
confirm
involvement
species
stereoselective
process.
The
synthetic
utility
has
been
demonstrated
through
rapid
assembly
iterative
oligopeptide,
showcasing
its
versatile
platform
for
late-stage
modification
drug
candidates.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(33)
Published: May 31, 2024
Catalytic
enantioselective
alkenylation
of
aldehydes
with
easily
accessible
alkenyl
halides
promoted
by
a
chiral
cobalt
complex
derived
from
newly
developed
tridentate
bisoxazolinephosphine
is
presented.
Such
processes
represent
an
unprecedented
reaction
pathway
for
catalysis
and
general
approach
that
enable
rapid
construction
highly
diversified
enantioenriched
allylic
alcohols
containing
1,1-,
1,2-disubstituted
trisubstituted
alkene
as
well
axial
stereogenicity
in
up
to
99
%
yield
:
1
er
without
the
need
preformation
alkenyl-metal
reagents.
DFT
calculations
revealed
origin
enantioselectivity.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
60(37), P. 20204 - 20209
Published: July 2, 2021
Abstract
A
Co‐catalyzed
enantioselective
desymmetric
[2+2+2]
cycloaddition
for
synthesis
of
pyridines
with
all‐carbon
quaternary
carbon
centers
has
been
developed.
The
regio‐
and
enantioselectivities
are
controlled
by
the
inherent
nature
terminal
alkynes
substituents
on
bisoxazolinephosphine
ligands.
Pyridines
5‐substitutents
could
be
obtained
>20:1
regioselectivity
up
to
94
%
ee
when
alkyl,
alkenyl
or
silyl
DTBM/Ph‐based
NPN*
ligand
L6
were
used.
Terminal
aryl
Ph/Bn‐based
L4
leads
formation
6‐substitutents
in
99
.
