Nature Communications,
Journal Year:
2023,
Volume and Issue:
14(1)
Published: May 22, 2023
We
herein
describe
an
asymmetric
α-allylic
allenylation
of
β-ketocarbonyls
and
aldehydes
with
1,3-enynes.
A
synergistic
chiral
primary
amine/Pd
catalyst
was
identified
to
facilitate
the
utilization
1,3-enynes
as
atom-economic
achiral
allene
precursors.
The
catalysis
enables
construction
all-carbon
quaternary
centers-tethered
allenes
bearing
non-adjacent
1,3-axial
central
stereogenic
centers
in
high
level
diastereo-
enantio-selectivity.
By
switching
configurations
ligands
aminocatalysts,
diastereodivergence
can
be
achieved
any
four
diastereoisomers
accessed
enantio-
selectivity.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(32), P. 12622 - 12632
Published: Aug. 5, 2021
In
contrast
to
the
widely
explored
methods
for
asymmetric
synthesis
of
molecules
bearing
a
single
stereocenter
or
adjacent
stereocenters,
concurrent
construction
1,3-stereogenic
centers
in
an
enantio-
and
diastereoselective
manner
remains
challenge,
especially
acyclic
systems.
Herein,
we
report
diastereodivergent
1,3-nonadjacent
stereocenters
allenyl
axial
central
chirality
through
synergistic
Pd/Cu-catalyzed
dynamic
kinetic
allenylation
with
racemic
allenylic
esters.
The
protocol
is
suitable
wide
range
substrates
including
challenging
esters
less
sterically
bulky
substituents
provided
chiral
products
high
levels
diastereoselectivities
(up
>20:1
dr
>99%
ee).
Furthermore,
several
representative
transformations
involving
axial-to-central
transfer
were
conducted,
affording
useful
structural
motifs
containing
nonadjacent
manner.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(45)
Published: Aug. 2, 2022
Abstract
Bimetallic
catalysis
has
emerged
as
an
efficient
strategy
for
the
development
of
new
chemical
reactions.
Importantly,
this
also
provides
a
simple
and
powerful
platform
stereodivergent
synthesis,
whereby
all
possible
stereoisomers
products
bearing
two
stereocenters
can
be
easily
prepared
from
same
set
starting
materials.
In
Minireview,
allylic
substitution,
propargylic
hydrofunctionalization,
annulation
based
on
bimetallic
been
summarized.
It
is
expected
that
more
catalytic
systems
will
developed
applied
synthesis
valuable
molecules.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
60(47), P. 24941 - 24949
Published: Sept. 17, 2021
The
development
of
efficient
and
straightforward
methods
for
obtaining
all
optically
active
isomers
structurally
rigid
spirocycles
from
readily
available
starting
materials
is
great
value
in
drug
discovery
chiral
ligand
development.
However,
the
stereodivergent
synthesis
bearing
multiple
stereocenters
remains
an
unsolved
challenge
owing
to
steric
hindrance
ring
strain.
Herein,
we
report
enantio-
diastereodivergent
through
dual-metal-catalyzed
[3+2]
annulation
oxy
π-allyl
metallic
dipoles
with
less
commonly
employed
nucleophilic
(imino
esters).
A
series
spiro
compounds
a
pyrroline
olefin
were
easily
synthesized
manner
(up
19:1
dr,
>99
%
ee),
which
showed
promise
as
new
type
N-olefin
ligand.
Preliminary
mechanistic
studies
also
carried
out
understand
process
this
bimetallic
catalysis.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
60(47), P. 24930 - 24940
Published: Oct. 11, 2021
By
virtue
of
a
fundamentally
new
reaction
model
azomethine
ylide
serving
as
two-atom
synthon,
we
present
the
first
example
stereodivergent
preparation
γ-butyrolactones
via
synergistic
Cu/Ir-catalyzed
asymmetric
cascade
allylation/lactonization,
and
all
four
stereoisomers
bearing
two
vicinal
stereocenters
are
accessible
with
excellent
diastereoselective
enantioselective
control.
The
chiral
IrIII
-π-allyl
intermediate
was
separated
characterized
to
understand
origin
regio-
stereoselectivity
initial
C-C
bond
formation
process.
Control
experiments
shed
some
light
on
catalyst/substrate
catalyst/catalyst
interactions
in
this
dual
catalytic
system
rationalize
related
kinetic/dynamic
kinetic
resolution
process
different
catalyst
combinations.
enantioenriched
γ-butyrolactone
products
were
converted
into
an
array
structurally
complex
molecules
organocatalysts
that
otherwise
inaccessible.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(4), P. 1971 - 1985
Published: Jan. 20, 2022
Comprehensive
computational
studies
were
carried
out
to
explore
the
mechanisms
of
enantioselective
Cu/Pd
and
stereodivergent
Cu/Ir
dual-catalytic
syntheses
α,α-disubstituted
α-amino
acids
(α-AAs).
A
chiral
copper
azomethine
ylide
undergoes
facile
α-allylation
with
racemic
π-allylpalladium
species
or
stereopure
π-allyliridium
complex
stereoconvergently
stereodivergently
furnish
single/double
stereocenters,
respectively.
Stereoselectivity
at
α-center
is
controlled
by
facial
selectivity
respect
prochiral
nucleophile.
Despite
apparently
similar
transition-state
assemblies,
models
distortion/interaction
analyses
disclose
versatile
modes
stereoinduction
wherein
can
face-selectively
intercept
metal−π-allyl
intermediates
utilizing
attractive
dispersion
interactions
and/or
sterically
caused
distortions.
Generation
β-stereocenter
in
system
relies
on
a
stereospecifically
generated
allyliridium
electronically
branched-to-linear
selectivity,
while
dual
yields
linear
monochiral
product
due
steric
factors
π–π
stacking
interactions.
The
demonstrate
molecular
level
how
ligand-encoded
information
transferred
α-/β-sites
resulting
α-AAs
mode
regio-/stereoselection
altered
differences
transition-metal-stabilized
coupling
partners.
To
facilitate
stereoselective
catalysis,
suite
analytical
tools
extract
controlling
for
asymmetric
induction
demonstrated.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(36)
Published: June 28, 2022
An
unprecedented
hydroalkylation
of
racemic
allylic
alcohols
and
ketimine
esters
enabled
by
Cu/Ru
relay
catalysis
has
been
developed
via
merging
the
ruthenium-catalyzed
asymmetric
borrowing-hydrogen
reaction
with
a
copper-catalyzed
Michael
addition
in
one-pot
procedure.
The
current
method
enables
efficient
preparation
highly
functionalized
δ-hydroxyesters
bearing
1,4-nonadjacent
stereocenters
good
yields
high
levels
diastereoselectivity
excellent
enantioselectivity
under
mild
conditions.
full
complement
four
stereoisomers
products
could
be
readily
accessed
orthogonal
permutations
two
chiral
metal
catalysts.
work
highlights
power
for
stereodivergent
construction
that
were
otherwise
inaccessible.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(9)
Published: Jan. 3, 2023
The
stereodivergent
synthesis
of
allene
compounds
bearing
α,β-adjacent
central
chiralities
has
been
realized
via
the
Pd/Cu-catalyzed
dynamic
kinetic
asymmetric
alkylation
racemic
allenylic
esters.
matched
reactivity
bimetallic
catalytic
system
enables
challenging
reaction
aryl-substituted
acetates
with
sterically
crowded
aldimine
esters
smoothly
under
mild
conditions.
Various
chiral
non-natural
amino
acids
a
terminal
allenyl
group
are
easily
synthesized
in
high
yields
and
excellent
diastereo-
enantioselectivities
(up
to
>20
:
1
dr,
>99
%
ee).
Importantly,
all
four
stereoisomers
product
can
be
readily
accessed
by
switching
configurations
two
metal
catalysts.
Furthermore,
easy
interconversion
between
uncommon
η3
-butadienyl
palladium
intermediate
featuring
weak
C=C/Pd
coordination
bond
stable
Csp2
-Pd
is
beneficial
for
transformation
process
(DyKAT).
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(7), P. 3915 - 3925
Published: Feb. 10, 2023
The
straightforward
construction
of
stereogenic
centers
bearing
unprotected
functional
groups,
as
in
nature,
has
been
a
persistent
pursuit
synthetic
chemistry.
Abundant
applications
free
enantioenriched
allyl
alcohol
and
hydroxylamine
motifs
have
made
the
asymmetric
hydration
hydroaminoxylation
conjugated
dienes
from
water
hydroxylamine,
respectively,
intriguing
efficient
routes
that
have,
however,
unachievable
thus
far.
A
fundamental
challenge
is
failure
to
realize
transition-metal-catalyzed
enantioselective
C–O
bond
constructions
via
hydrofunctionalization
dienes.
Here,
we
perform
comprehensive
study
toward
stereoselective
formal
by
synthesizing
set
new
P,N-ligands
identifying
an
aryl-derived
oxime
surrogate
for
both
hydroxylamine.
Asymmetric
hydroalkoxylation
with
also
elucidated.
Furthermore,
versatile
derivatizations
following
provide
indirect
but
concise
hydrophenoxylation,
hydrofluoroalkoxylation,
hydrocarboxylation
unreported
Finally,
ligand-to-ligand
hydrogen
transfer
process
proposed
based
on
results
preliminary
mechanistic
experiments.