The Chemical Record,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 27, 2024
Carbohydrates
are
natural,
renewable,
chemical
compounds
that
play
crucial
roles
in
biological
systems.
Thus,
efficient
and
stereoselective
glycosylation
is
an
urgent
task
for
the
preparation
of
pure
structurally
well-defined
carbohydrates.
Photoredox
catalysis
has
emerged
as
a
powerful
tool
carbohydrate
chemistry,
providing
alternative
addressing
some
challenges
glycochemistry.
Over
last
few
decades,
Ir-
Ru-based
organometallic
photocatalysts
have
attracted
significant
interest
because
their
high
stability,
high-energy
triplet
state,
strong
visible-light
absorption,
long
luminescence
lifetime,
amenability
to
ligand
modification.
This
review
highlights
recent
progress
photocatalyst-promoted
synthesis
modification
carbohydrates
under
photoirradiation,
well
related
benefits
drawbacks.
Chemical Science,
Год журнала:
2024,
Номер
15(4), С. 1204 - 1236
Опубликована: Янв. 1, 2024
This
review
article
highlights
the
diverse
ways
in
which
recent
developments
areas
of
photocatalysis
and
visible
light
photochemistry
are
impacting
synthetic
carbohydrate
chemistry.
ACS Catalysis,
Год журнала:
2024,
Номер
14(15), С. 11532 - 11544
Опубликована: Июль 19, 2024
Glycosyl
donor
activation
emerged
as
an
enabling
technology
for
anomeric
functionalization,
but
aimed
primarily
at
O-glycosylation.
In
contrast,
we
herein
disclose
mechanistically
distinct
electrochemical
glycosyl
bromide
activations
via
halogen-atom
transfer
and
C-glycosylation.
The
radical
addition
to
alkenes
led
C-alkyl
glycoside
synthesis
under
precious
metal-free
reaction
conditions
from
readily
available
bromides.
robustness
of
our
e-XAT
strategy
was
further
mirrored
by
C-aryl
C-acyl
glycosides
assembly
through
nickela-electrocatalysis.
Our
approach
provides
orthogonal
with
expedient
scope,
hence
representing
a
general
method
direct
C-glycosides
assembly.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(17), С. 11909 - 11920
Опубликована: Авг. 9, 2024
Melibiosamine
(Gal-α(1,6)-GlcNH2),
consisting
of
galactose
and
glucosamine
linked
by
an
α(1,6)-glycosidic
bond,
is
artificial
disaccharide
derivative
that
selectively
inhibits
the
proliferation
K562
tumor
cells
relative
to
HUC-F2
normal
cells.
In
this
study,
we
employed
a
linkage-editing
strategy
synthesize
CH2-
CHF-linked
melibiosamine
analogs
through
chemo-
stereoselective
hydrogenation
fluorovinyl-C-glycoside.
(R)-CHF-Melibiosamine
exhibited
more
potent
antiproliferative
activity
than
O-linked
melibiosamine,
while
(S)-CHF-melibiosamine
was
less
potent.
Aryl
migration,
especially
1,4-aryl
is
one
of
the
most
important
reactions
in
radical
rearrangement.
Over
past
decades,
migration
by
addition
a
to
alkynes
has
become
simple
and
efficient
method
difunctionalization
alkynes.
Radical-based
aryl
alkynoates
been
well-explored;
however,
propynyl
ethers
rarely
studied.
Herein,
we
first
described
propargyl
ether
valuable
α,β-unsaturated
aldehydes
via
photoredox
Ni
catalysis.
This
features
redox-neutral
conditions,
readily
available
starting
materials,
broad
substrate
scope,
good
functional
group
compatibility,
diverse
transformations.
Mechanistic
studies
suggest
that
this
reaction
proceeds
through
radical-involved
pathway.
A
visible
light-promoted,
mild,
and
efficient
Ir(III)-catalyzed
synthesis
of
C-nucleosides
is
reported,
utilizing
1-bromosugar
as
the
glycosyl
radical
precursor
6-azauracil
nucleobase.
The
method
exhibits
high
α-selectivity
excellent
functional
group
tolerance.
Spectroscopic
evidence
shows
that
coupling
reaction
happens
via
initial
reductive
quenching
Ir(III)
catalyst
under
light.
Density
theory
calculation
reveals
reason
for
complete
α-selectivity.
Finally,
biologically
active
6-aza
pseudouridine
analogues
were
synthesized,
making
process
a
valuable
platform
C-nucleosides.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(36)
Опубликована: Июнь 5, 2024
Previous
N-glycosylation
approaches
have
predominately
involved
acidic
conditions,
facing
challenges
of
low
stereoselectivity
and
limited
scope.
Herein,
we
introduce
a
radical
activation
strategy
that
enables
versatile
stereoselective
using
readily
accessible
glycosyl
sulfinate
donors
under
basic
conditions
exhibits
exceptional
tolerance
towards
various
N-aglycones
containing
alkyl,
aryl,
heteroaryl
nucleobase
functionalities.
Preliminary
mechanistic
studies
indicate
pivotal
role
iodide,
which
orchestrates
the
formation
from
subsequent
generation
key
intermediate,
configurationally
well-defined
is
subsequently
attacked
by
an
N-aglycone
in
stereospecific
S
Nature Communications,
Год журнала:
2024,
Номер
15(1)
Опубликована: Окт. 24, 2024
C-Glycosides
are
essential
for
the
study
of
biological
processes
and
development
carbohydrate-based
drugs.
Despite
tremendous
hurdles,
glycochemists
have
often
fantasized
about
efficient,
highly
stereoselective
synthesis
C-glycosides
with
shortest
steps
under
mild
conditions.
Herein,
we
report
a
desulfurative
radical
protocol
to
synthesize
C-alkyl
glycosides
coumarin
visible-light
induced
conditions
without
need
an
extra
photocatalyst,
in
which
stable
readily
available
glycosyl
thiols
that
could
be
obtained
from
native
sugars
activated
situ
by
pentafluoropyridine.
The
benefits
this
procedure
include
high
stereoselectivity,
broad
substrate
scope,
easy
handling.
Mechanistic
studies
indicate
produced
tetrafluoropyridyl
S-glycosides
form
key
electron
donor-acceptor
(EDA)
complexes
Hantzsch
ester
(for
glycosides)
or
Et
