Direct Construction of C‐Alkyl Glycosides from Non‐Activated Olefins via Nickel‐Catalyzed C(sp3)─C(sp3) Coupling Reaction
Advanced Science,
Год журнала:
2024,
Номер
11(12)
Опубликована: Янв. 18, 2024
Among
C-glycosides,
C-alkyl
glycosides
are
significant
building
blocks
for
natural
products
and
glycopeptides.
However,
research
on
efficient
construction
methods
remains
relatively
limited.
Compared
with
Michael
acceptors,
non-activated
olefins
more
challenging
substrates
have
rarely
been
employed
in
the
of
C-glycosides.
Here,
a
highly
convenient
approach
synthesis
through
nickel-catalyzed
C(sp
Язык: Английский
Visible-light-promoted direct desulfurization of glycosyl thiols to access C-glycosides
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
Язык: Английский
Visible-Light-Promoted Direct Desulfurization of Glycosyl Thiols to Access of C-Glycosides
Research Square (Research Square),
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 3, 2024
Abstract
C-Glycosides
are
essential
for
the
study
of
biological
processes
and
development
carbohydrates-based
drugs.
Despite
tremendous
hurdles,
glycochemists
have
often
fantasized
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
in
two
or
three
from
native
sugars
activated
situ
by
pentafluoropyridine.
The
benefits
this
procedure
include
high
stereoselectivity,
broad
substrates
scope,
easily
handle.
Mechanistic
studies
indicated
produced
tetrafluoropyridyl
S-glycosides
formed
key
EDA
complexes
Hantzsch
ester
(for
C-alkyl
glycosides)
Et
3N
coumarin
C-glycosides),
upon
irradiation
visible
light,
triggered
cascade
process
access
smoothly.
Язык: Английский
Palladium‐Catalyzed Directing‐group‐mediated γ‐C(sp3)‐H Glycosylation for Synthesis of C‐Alkyl Glycosides
Advanced Synthesis & Catalysis,
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 29, 2024
Abstract
C
‐alkyl
glycosides
play
a
crucial
role
in
various
bioactive
compounds.
However,
the
synthesis
of
poses
significant
challenges,
particularly
through
C(
sp
3
)−H
glycosylation.
Here,
we
report
set
reactions
for
constructing
directing‐group‐mediated
functionalization
unactivated
γ
‐C(
bonds
under
mild
conditions.
These
not
only
achieve
high
regioselectivity
and
stereoselectivity
glycosylation,
but
also
exhibit
wide
substrate
scope.
They
are
compatible
with
both
arene
alkane
substrates,
as
well
natural
unnatural
amino
acid
substrates.
Mechanistic
studies
have
shown
that
directing‐group
8‐aminoquinoline
(AQ)
picolinamide
(PA)
may
affect
chirality
β
‐carbon
L
‐valine
sterically
favorable
trans
‐palladacycle
intermediate,
resulting
(
R
)
or
S
configuration
glycosylated
acid,
respectively.
promising
to
provide
convenient
powerful
tool
carbohydrate‐based
drugs
future.
Язык: Английский