A
Pd-catalyzed
asymmetric
Heck
cascade
reaction
involving
the
intramolecular
carbopalladation
of
unsaturated
hydrocarbons,
followed
by
nucleophilic
trapping
resulting
palladium
species,
is
a
powerful
approach
for
constructing
chiral
N-heterocycles.
However,
use
prochiral
nucleophiles
in
these
reactions
remains
significantly
underexplored.
Herein,
we
report
novel
Pd/Cu
catalytic
system
Heck/Tsuji–Trost
allenamides
and
aldimine
esters.
This
robust
method
allows
rapid
synthesis
wide
range
enantiopure
non-natural
α-substituted
tryptophans
high
yields
(up
to
99%
yield)
with
excellent
enantioselectivities
98%
ee).
Additionally,
synthetic
utility
this
protocol
demonstrated
through
scale-up
experiments
diverse
valuable
transformations.
The
stereodivergent
synthesis
of
δ-lactones,
which
are
prevalent
in
natural
product
frameworks,
from
simple
starting
materials
via
a
single
transformation
remains
significant
challenge.
Herein,
we
report
an
enantio-
and
diastereodivergent
cascade
reaction
for
the
modular
chiral
δ-lactones
bearing
two
nonadjacent
quaternary
tertiary
carbon
stereocenters.
This
approach
employs
bimetallic
Ru/Cu
relay
catalysis
between
allylic
alcohols
azaaryl
acetates.
method
integrates
Ru-catalyzed
asymmetric
borrowing
hydrogen
reaction,
Cu-catalyzed
Michael
addition,
rapid
lactonization
into
one-pot
process,
with
all
catalysts
substrates
introduced
at
outset.
By
orthogonal
permutation
metal
catalysts,
precise
control
over
relative
absolute
configurations
newly
formed
stereocenters
is
achieved,
allowing
selective
access
to
stereoisomers
δ-lactone
products
predictable
efficient
manner.
Advanced Science,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 25, 2024
The
development
of
efficient
methodologies
for
the
controlled
manufacture
specific
stereoisomers
bearing
quaternary
stereocenters
has
prompted
advances
in
a
variety
scientific
disciplines
including
pharmaceutical
chemistry,
materials
science,
and
chemical
biology.
However,
complete
control
absolute
relative
stereochemical
configurations
alkyne
derivatives
remains
an
unmet
synthetic
challenge.
Herein,
Ni/Cu
dual-catalyzed
asymmetric
propargylic
substitution
reaction
is
presented
to
produce
propargylated
products
with
all-carbon
high
yields
significant
diastereo-
enantioselectivities
(up
>20:1
dr,
>99%
ee).
synthesis
all
variants
methohexital,
widely
used
sedative-hypnotic
drug,
exemplifies
efficacy
stereodivergent
propargylation.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 2, 2024
Understanding
the
nature
of
a
transition-metal-catalyzed
process,
including
catalyst
evolution
and
real
active
species,
is
rather
challenging
yet
great
importance
for
rational
design
development
novel
catalysts,
this
even
more
difficult
bimetallic
catalytic
system.
Pd(0)/carboxylic
acid
combined
system-catalyzed
allylic
alkylation
reaction
alkynes
has
been
used
as
an
atom-economical
protocol
synthesis
products.
However,
asymmetric
version
still
limited,
in-depth
understanding
Pd
species
elusive.
Herein
we
report
enantioselective
coupling
between
readily
available
aldimine
esters
using
synergistic
Cu/Pd
system,
affording
diverse
set
α-quaternary
allyl
amino
ester
derivatives
in
good
yields
with
excellent
enantioselectivities.
Mechanistic
studies
indicated
that
it
most
likely
molecular
Cu
catalysis
nanoparticle
catalysis.
The
precursor
transformed
to
soluble
nanoparticles
Organic Letters,
Год журнала:
2024,
Номер
26(44), С. 9598 - 9603
Опубликована: Окт. 28, 2024
A
photoinduced
three-component
radical
addition-aminalization
cascade
was
accomplished,
enabling
rapid
assembly
of
a
wide
range
densely
functionalized
γ-lactams.
Key
to
this
transformation
is
the
electron-donor-acceptor
(EDA)
generation
enamine
and
in
situ
trapping
an
iminium
intermediate
with
bromodifluoroacetamide.
This
rationally
designed
protocol
fully
takes
advantage
polarity
crossover
(enamine-iminium)
process,
providing
modular
previously
inaccessible
scaffolds.
The
reaction
proceeds
under
mild
conditions
excellent
regio-
diastereoselectivity,
which
amenable
structurally
varied
substrates
pharmaceuticals.
Dual
catalysis
is
a
powerful
strategy
for
developing
new
organic
reactions
that
used
to
be
challenging
achieve
by
traditional
methods.
Whether
through
relay
or
synergistic
catalysis,
it
does
not
only
facilitate
complicated
multiple
bond
formations
but
also
enriches
the
toolbox
constructing
novel
molecules.
In
this
Thieme
Cheminar,
chaired
SYNTHESIS
Editor
Jung
Min
Joo,
our
speakers
will
present
their
latest
research
on
dual
catalysis.
Speaker
line-up:
•
Weiwei
Zi
(Nankai
University)
-
“Synergistic
Catalysis
Enabled
Stereodivergent
Csp3–Csp3
Coupling
Reactions”
Philip
Wai
Hong
Chan
(Monash
“Recent
adventures
at
intersection
of
Brønsted
acid,
gold
and
photoredox
catalysis”
Chun-Jiang
Wang
(Wuhan
with
Azomethine
Ylides”
This
Cheminar
particular
interest
chemistry
students,
graduates,
researchers
in
industry
academia.
Sign
up
now
save
your
spot!
Synergistic
Reactions
Vicinal
stereocenters
are
commonly
found
natural
products,
bioactive
molecules,
potential
drugs.
Constructing
vicinal
Csp3-Csp3
formation
significant
focus
asymmetric
Over
past
five
years,
group
has
concentrated
platform
stereodivergent
coupling
using
Pd-involved
We
have
integrated
nucleophile-activation
modes
into
Pd
allowing
us
pursue
series
dienes
(including
1,3-dienes,
alkoxyallenes,
allenamides)
various
carbon
nucleophiles,
such
as
aldimine
esters,
aldehydes,
oxindoles,
pentafluorophenyl
esters.
These
provide
quick
access
variety
chiral
scaffolds
containing
manner.
Recent
One
most
synthetic
tools
emerge
over
years
rapidly
molecular
complexity
from
readily
accessible
precursors
an
enantioselective
manner
catalysis.[1]
presentation,
we
disclose
recent
contributions
field
chemical
synthesis
acid
core
these
studies.[2–5]
highlight
study
realised
method
chemo-
assembly
1,8-dihydroindeno[2,1-b]pyrroles
pyrrol-2-yl
methanols
exploited
gold(I)-
“hidden”
acid-catalysed
*β*-amino-1,4-enynols.[2–4]
presence
*N*-triflyl
phosphoramide,
tandem
dehydrative
Nazarov-type
electrocyclisation/hydroamination
substrate
was
selectively
occur
afford
synthetically
useful
indeno-fused
pyrrole
derivative.[6]
On
other
hand,
changing
phosphoric
observed
result
hydroamination/enantioselective
formal
1,3-allylic
alcohol
isomerisation
cascade
give
1*H*-pyrrole.
An
electron-donor
acceptor
complex,
generated
Hantzsch
ester
*N*-(acyloxy)phthalimide
ester,
catalytic
system
enable
Minisci-type
C2-alkylation
quinolines,
isoquinolines
pyridines
under
blue
light
emitting
diode
(456
nm)
discussed.[5]
Ylides
emerged
reaction
development
Through
effect
between
different
systems,
simultaneous
activation
components
can
realized,
which
effectively
reduces
barriers
improves
activity
efficiency,
thus
realizing
transformations
impossible
inefficient
mono-catalysis,
especially
molecules
stereogenic
centers.
I
report
progress
metallated
azomethine
ylides
stereochemically
controllable
nucleophilic
reagents.
