ACS Catalysis,
Год журнала:
2023,
Номер
13(7), С. 4894 - 4902
Опубликована: Март 27, 2023
C-4-selective
functionalization
of
azlactones
provides
access
to
α,α-disubstituted
unnatural
α-amino
acids,
which
has
been
extensively
investigated
in
the
past
decades.
However,
a
vast
majority
such
transformations
are
two-electron
transfer
reactions.
Herein,
leveraging
on
persistent
radical
effect,
we
develop
photocatalytic
energy
transfer-enabled
regioconvergent
alkylation
with
redox-active
esters
via
radical–radical
couplings.
This
strategy
is
extended
utilization
simple
alkanes
as
precursors,
whereby
aryl
play
dual
role
an
oxidant
and
hydrogen-atom-transfer
agent.
Notably,
excited
state
Ir(III)
photocatalyst
enables
selective
activation
unwanted
imine
products
through
triplet
transfer,
delivering
C-4-functionalized
high
regioselectivity.
Both
experimental
investigations
density
functional
theory
calculations
reaction
mechanism
were
performed,
supporting
EnT-enabled
coupling
pathways.
Chemical Science,
Год журнала:
2023,
Номер
14(40), С. 11170 - 11179
Опубликована: Янв. 1, 2023
A
catalyst-free
photosensitized
strategy
has
been
developed
for
regioselective
imino
functionalizations
of
alkenes
via
the
formation
an
EDA
complex.
This
photo-induced
protocol
facilitates
construction
structurally
diverse
β-imino
sulfones
and
vinyl
in
moderate
to
high
yields.
Mechanistic
studies
reveal
that
reaction
is
initiated
with
intermolecular
charge
transfer
between
oximes
sulfinates,
followed
by
fragmentation
generate
a
persistent
iminyl
radical
transient
sulfonyl
radical.
also
features
excellent
regioselectivity,
broad
functional
group
tolerance
mild
conditions.
The
late
stage
functionalization
natural
product
derived
compounds
total
synthesis
some
bioactive
molecules
have
demonstrated
highlight
utility
this
protocol.
Meanwhile,
compatibility
different
donors
proved
generality
strategy.
Chemical Science,
Год журнала:
2023,
Номер
15(9), С. 3182 - 3191
Опубликована: Дек. 21, 2023
Two
complementary
strain-enabled
radical
spirocyclization
cascades
have
been
realized
to
synthesize
spirocyclobutyl
lactones
and
–
lactams.
The
reactions
operate
under
mild
conditions
demonstrate
excellent
functional
group
compatibility.
ACS Catalysis,
Год журнала:
2023,
Номер
13(7), С. 4894 - 4902
Опубликована: Март 27, 2023
C-4-selective
functionalization
of
azlactones
provides
access
to
α,α-disubstituted
unnatural
α-amino
acids,
which
has
been
extensively
investigated
in
the
past
decades.
However,
a
vast
majority
such
transformations
are
two-electron
transfer
reactions.
Herein,
leveraging
on
persistent
radical
effect,
we
develop
photocatalytic
energy
transfer-enabled
regioconvergent
alkylation
with
redox-active
esters
via
radical–radical
couplings.
This
strategy
is
extended
utilization
simple
alkanes
as
precursors,
whereby
aryl
play
dual
role
an
oxidant
and
hydrogen-atom-transfer
agent.
Notably,
excited
state
Ir(III)
photocatalyst
enables
selective
activation
unwanted
imine
products
through
triplet
transfer,
delivering
C-4-functionalized
high
regioselectivity.
Both
experimental
investigations
density
functional
theory
calculations
reaction
mechanism
were
performed,
supporting
EnT-enabled
coupling
pathways.
