Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(28), С. 15611 - 15618
Опубликована: Июль 5, 2023
Asymmetric
epoxidation
of
alkenes
catalyzed
by
nonheme
chiral
Mn–O
and
Fe–O
catalysts
has
been
well
established,
but
Co–O
for
the
purpose
remain
virtually
undeveloped
due
to
oxo
wall.
Herein
is
first
reported
a
cobalt
complex
realize
enantioselective
cyclic
acyclic
trisubstituted
using
PhIO
as
oxidant
in
acetone,
wherein
tetra-oxygen-based
N,N′-dioxide
with
sterically
hindered
amide
subunits
plays
crucial
role
supporting
formation
intermediate
electrophilic
oxygen
transfer.
Mechanistic
studies,
including
HRMS
measurements,
UV–vis
absorption
spectroscopy,
magnetic
susceptibility,
DFT
calculations,
were
carried
out,
confirming
species
quartet
Co(III)-oxyl
tautomer.
The
mechanism
origin
enantioselectivity
also
elucidated
based
on
control
experiments,
nonlinear
effects,
kinetic
calculations.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(48), С. 22140 - 22149
Опубликована: Ноя. 22, 2022
Photocatalysis
opens
up
a
new
window
for
carbonyl
chemistry.
Despite
multitude
of
photochemical
reactions
compounds,
visible
light-induced
catalytic
asymmetric
transformations
remain
elusive
and
pose
formidable
challenge.
Accordingly,
the
development
simple,
efficient,
economic
systems
is
ideal
pursuit
chemists.
Herein,
we
report
an
enantioselective
radical
photoaddition
to
ketones
through
Lewis
acid-enabled
photoredox
catalysis
wherein
in
situ
formed
chiral
N,N'-dioxide/Sc(III)-ketone
complex
serves
as
temporary
photocatalyst
trigger
single-electron
transfer
oxidation
silanes
generation
nucleophilic
species,
including
primary,
secondary,
tertiary
alkyl
radicals,
giving
various
enantioenriched
aza-heterocycle-based
alcohols
good
excellent
yields
enantioselectivities.
The
results
electron
paramagnetic
resonance
(EPR)
high-resolution
mass
spectrum
(HRMS)
measurements
provided
favorable
evidence
stereocontrolled
addition
process
involved
this
reaction.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(29)
Опубликована: Апрель 21, 2022
Abstract
The
ubiquity
of
sulfur‐containing
molecules
in
biologically
active
natural
products
and
pharmaceuticals
has
long
attracted
synthetic
chemists
to
develop
efficient
strategies
towards
their
synthesis.
strategy
direct
α‐C(sp
3
)−H
modification
sulfides
provides
a
streamlining
access
complex
molecules.
Herein,
we
report
photoinduced
chemo‐,
site‐
stereoselective
functionalization
using
isatins
as
the
photoredox
reagent
coupling
partner
catalyzed
by
chiral
gallium(III)‐
N,N
′‐dioxide
complex.
reaction
proceeds
through
verified
single‐electron
transfer
(SET)
mechanism
with
high
efficiency,
excellent
functional
group
tolerance,
well
broad
substrate
scope.
Importantly,
this
cross‐coupling
protocol
is
highly
selective
for
late‐stage
methionine‐related
peptides,
regardless
inherent
structural
similarity
complexity
diverse
residues.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
10(14), С. 3676 - 3683
Опубликована: Янв. 1, 2023
Privileged
Feng
ligands
feature
designer
N
,
’-dioxide
amides
with
a
unique
conformational
and
coordination
flexibility.
This
highlight
summarizes
the
increasingly
profound
impact
of
on
modern
catalytic
asymmetric
synthesis.
Acta Chimica Sinica,
Год журнала:
2023,
Номер
81(11), С. 1522 - 1522
Опубликована: Янв. 1, 2023
Chiral
molecules
are
ubiquitous
in
nature
and
play
an
important
role
natural
products,
pharmaceuticals,
agriculture,
advanced
materials,
as
well
living
organisms.Therefore,
the
development
of
efficient
strategies
to
enable
facile
construction
enantiopure
chiral
compounds
atom-and
step-economical
manner
is
great
importance.The
enantioselective
functionalization
C-H
bonds
without
multi-steps
transformation
arguably
one
most
powerful
straightforward
fulfill
this
goal.This
emerging
research
field
has
been
rapidly
developed
with
innovation
various
catalysts
and/or
ligands
recent
years.In
particular,
significant
advances
have
achieved
palladium-catalyzed
C(sp
3
)-H
bonds,
streamlining
concise
from
readily
available
hydrocarbon
feedstocks.The
stereoselective
assistance
ligand
form
a
palladacycle
intermediate,
which
could
be
transformed
into
chemical
functionalized
compounds,
attracted
tremendous
attention.Thus,
perspective
summarizes
on
palladium(II)-catalyzed
via
asymmetric
palladation.According
type
classified
several
sections,
including
methyl
methylene
constrained
cycloalkanes,
adjacent
α-heteroatom,
benzylic
unbiased
bonds.The
emphasis
focuses
discussion
philosophy
developing
novel
mode
stereocontrol.The
remaining
limitations
challenges
regarding
chemo-and
control
also
discussed.Further
new
catalytic
systems
expected
address
these
issues
expands
scope
synthetic
strategy.We
anticipate
that
might
inspire
more
efforts
strategy
find
wide
applications
synthesis
complicated
molecules,
such
products
drugs.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(28), С. 15611 - 15618
Опубликована: Июль 5, 2023
Asymmetric
epoxidation
of
alkenes
catalyzed
by
nonheme
chiral
Mn–O
and
Fe–O
catalysts
has
been
well
established,
but
Co–O
for
the
purpose
remain
virtually
undeveloped
due
to
oxo
wall.
Herein
is
first
reported
a
cobalt
complex
realize
enantioselective
cyclic
acyclic
trisubstituted
using
PhIO
as
oxidant
in
acetone,
wherein
tetra-oxygen-based
N,N′-dioxide
with
sterically
hindered
amide
subunits
plays
crucial
role
supporting
formation
intermediate
electrophilic
oxygen
transfer.
Mechanistic
studies,
including
HRMS
measurements,
UV–vis
absorption
spectroscopy,
magnetic
susceptibility,
DFT
calculations,
were
carried
out,
confirming
species
quartet
Co(III)-oxyl
tautomer.
The
mechanism
origin
enantioselectivity
also
elucidated
based
on
control
experiments,
nonlinear
effects,
kinetic
calculations.
