Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 10, 2025
Achieving
catalytic
asymmetric
functionalization
of
methylenecyclopropanes
(MCPs)
by
selective
C–C
bond
cleavage
is
a
notable
challenge
due
to
the
intricate
reaction
partners
involved.
In
this
work,
we
report
that
chiral
aldehyde/palladium
combined
catalysis
enables
MCPs
with
NH2-unprotected
amino
acid
esters.
This
proceeds
through
regiospecific
branched
ring-opening
mechanism,
resulting
in
optically
active
α,α-disubstituted
α-amino
esters
bearing
nonconjugated
terminal
alkene
units.
Mechanism
studies
indicate
pathways
are
irreversible
and
ultimate
regioselectivity
governed
palladium
catalysis.
The
products
can
be
utilized
construction
dihydropyrazoles,
α-methyl
aspartic
derivatives,
analogues
VPC01091
BMS-986104.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(48)
Опубликована: Авг. 14, 2024
Silacycles
have
exhibited
significant
potential
for
application
in
the
fields
of
medicinal
chemistry,
agrochemistry,
and
materials
science.
Accordingly,
development
effective
methods
synthesizing
these
compounds
has
attracted
increasing
attention.
Here,
we
report
an
efficient
Cu-catalyzed
enantioselective
hydrosilylation
arylmethylenecyclopropanes
with
hydrosilanes,
that
allows
rapid
assembly
various
enantioenriched
carbon-
silicon-stereogenic
silacyclopentanes
good
yields
excellent
enantioselectivities
diastereoselectivities
under
mild
conditions.
Further
stereospecific
transformation
Si-H
bond
on
chiral
silicon
center
expands
diversity
C-
Si-stereogenic
silacyclopentanes.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 18, 2024
Abstract
Despite
impressive
advances
in
the
construction
of
enantioenriched
silacarbocycles
featuring
silicon‐stereogenic
centers
via
a
selection
well‐defined
sila‐synthons,
development
more
convenient
and
economic
method
with
readily
available
starting
materials
is
significantly
less
explored
remains
considerable
challenge.
Herein,
we
report
first
example
copper‐catalyzed
sequential
hydrosilylation
accessible
methylenecyclopropanes
(MCPs)
primary
silanes,
affording
an
efficient
route
to
wide
range
chiral
silacyclopentanes
bearing
consecutive
silicon‐
carbon‐stereogenic
excellent
enantio‐
diastereoselectivities
(generally
≥98
%
ee,
>25
:
1
dr).
Mechanistic
studies
reveal
that
these
reactions
combine
intermolecular
ring‐opening
aryl
MCPs
intramolecular
asymmetric
resultant
Z
/
E
mixture
homoallylic
silanes.
ACS Catalysis,
Год журнала:
2024,
Номер
14(20), С. 15790 - 15798
Опубликована: Окт. 10, 2024
Here,
we
report
a
photoredox
and
nickel-catalyzed
cross-electrophile
coupling
strategy
for
the
asymmetric
three-component
1,2-alkylarylation
of
vinyl
boronates
with
(hetero)aryl
bromides
(2°,
3°)-alkyl
redox-active
esters
in
presence
Hantzsch
ester.
With
fluorinated
pyridyl-substituted
chiral
biimidazoline
ligand,
this
reaction
enables
straightforward
access
to
wide
variety
synthetically
valuable
α-aryl
from
readily
available
starting
materials.
This
features
mild
conditions,
broad
substrate
generality,
good
functional
group
tolerance
proceeds
without
using
metal
reductants
or
alkyl
halides.
Furthermore,
alkenyl
halides
other
electron-deficient
alkenes
such
as
acrylates
phosphonates
can
be
applied
successfully.
Preliminary
mechanistic
studies
shed
light
on
potential
pathways
roles
organic
amines.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(47), С. 32283 - 32291
Опубликована: Ноя. 13, 2024
Compounds
bearing
both
boryl
and
amino
groups
at
distal
positions
are
invaluable
synthons
for
synthesizing
pharmaceuticals,
drug
candidates,
natural
products,
but
their
catalytic
enantioselective
synthesis
remains
rarely
explored.
We
report
the
first
1,4-borylamination
reaction
through
a
copper-catalyzed
cascade
hydroborylation
hydroamination
of
arylidenecyclopropanes.
This
combines
four
readily
available
components
in
highly
chemo-,
site-,
fashion
(>20:1
r.r.
up
to
99%
ee),
yielding
diverse
array
synthetically
valuable
enantioenriched
4-amino
alkylboronates.
The
versatile
utility
these
products
is
highlighted
by
transformations
wide
applications
pharmaceutical
discovery.
Preliminary
mechanistic
studies
were
conducted
elucidate
operative
pathway,
intermediates,
origins
its
high
chemo-
site-selectivity.
The
enantioselective
ring-opening
reactions
of
methylenecyclopropanes
(MCPs)
involving
C–C
bond
activation
via
oxidative
addition
transition
metals
have
been
rarely
reported.
Here,
we
disclose
a
Pd/Cu-catalyzed
enantio-
and
regioselective
coupling
between
cyclic
imino
esters
MCPs
to
produce
α-allylated
2H-pyrrole
derivatives.
In
this
reaction,
azomethine
ylide
formed
by
chiral
copper
catalyst
with
ketimine
ester
would
serve
as
nucleophile
react
activated
palladium
catalysis.
This
bimetallic
system
exhibited
broad
substrate
scope
high
regio-
enantioselectivities.
Heteroatomic
groups
in
alkenes
typically
direct
thermodynamically
favored
chain
walking
of
C═C
bonds
toward
themselves,
thereby
facilitating
C-H
bond
functionalization
near
the
heteroatoms.
We
present
herein
an
efficient
cobalt-catalyzed
contra-thermodynamic
remote
hydroboration
alkenylboronates
with
pinacolborane
to
synthesize
chiral
1,n-diboronates.
This
protocol
features
a
broad
substrate
scope,
high
functional
group
tolerance,
and
excellent
enantioselectivity.
Mechanistic
studies
indicate
involvement
chain-walking
process.
Gram-scale
reactions
various
product
derivatizations
further
highlight
its
practicality.
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 25, 2025
Arylidenecyclobutanes
are
readily
accessible
and
versatile
reagents
in
synthetic
chemistry
due
to
the
multifaceted
reactivity
exhibited
by
their
alkene
strained
cyclobutane
moieties.
However,
metal-catalyzed
enantioselective
functionalization
of
arylidenecyclobutanes,
particularly
controllable
ring-retaining
ring-opening
reactions,
is
rarely
explored.
Considering
utility
enantioenriched
organoboronate
compounds,
herein
we
report
ligand-controlled
copper-catalyzed
hydroboration
dihydroboration
reactions
arylidenecyclobutanes
that
afford
chiral
α-cyclobutyl
benzylboronate
1,5-diboronate
compounds
with
high
enantioselectivity
when
(S)-DTBM-Segphos
(S,S)-Ph-BPE
employed,
respectively.
Mechanistic
studies
reveal
process
via
β-C
elimination
significantly
slower
than
arylidenecyclopropanes
presence
CuOAc
(S,S)-Ph-BPE.
The
these
two
protocols
further
demonstrated
through
conducting
various
stereospecific
site-selective
transformations
organoboron
products,
including
concise
synthesis
bioactive
molecules.
Abstract
Compounds
bearing
both
boryl
and
amino
groups
are
highly
valuable
synthons
in
organic
synthesis.
However,
while
enantioselective
1,1-
1,2-borylamination
reactions
have
been
developed,
processes
enabling
distal
borylamination
rarely
investigated.
Here,
we
present
an
1,4-borylamination
reaction,
achieved
through
a
copper-catalyzed
cascade
hydroborylation
hydroamination
of
arylidenecyclopropanes.
This
four-component
reaction
provides
direct
access
to
enantioenriched
4-aminoalkylboronate
products
with
high
chemo-,
site-,
enantioselectivity.
The
versatility
these
was
demonstrated
their
broad
transformations
extensive
applications
the
synthesis
various
drug
core
structures.
Additionally,
preliminary
mechanistic
studies
were
conducted
investigate
pathway,
intermediates,
chemo-
site-selectivity.
