We
report
here
a
new
catalytic
and
exclusively
cis-selective
glycosylation
strategy
for
multigram
scale
synthesis
of
biologically
valuable
Tn
antigens.
The
underlying
iron-catalyzed
glycal
1,2-cis-aminoglycosylation
method
is
effective
with
variety
galactosyl
donors
amino
acid
acceptors
consistently
high
stereoselectivity.
Rapid
scalable
postglycosylation
transformations
readily
afford
single
diastereomeric
antigens
in
yields.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(32), С. 22413 - 22423
Опубликована: Авг. 3, 2024
Stereochemically
pure
saccharides
have
indispensable
roles
in
fields
ranging
from
medicinal
chemistry
to
materials
science
and
organic
synthesis.
However,
the
development
of
a
simple,
stereoselective,
efficient
glycosylation
protocol
access
α-
β-C-glycosides
(particularly
2-deoxy
entities)
remains
persistent
challenge.
Existing
studies
primarily
focused
on
C1
modification
carbohydrates
transformation
glycosyl
radical
precursors.
Here,
we
innovate
by
harnessing
situ
generated
glycosyl-Ni
species
achieve
one-pot
borylation
cascade
manner,
which
is
enabled
an
earth-abundant
nickel-catalyzed
carboboration
readily
accessible
glycals
without
any
ligand.
This
work
reveals
potential
for
modular
multifunctional
platform
facilitate
simultaneous
introduction
C-C
C-B
bonds
at
stereogenic
center
saccharides,
largely
unexploited
research
area.
Preliminary
experimental
computational
indicate
that
endocyclic
O
C3
group
play
important
stereoseclectively
forging
glycosidic
bonds.
As
result,
diverse
range
C-R
(R
=
alkyl,
aryl,
alkenyl)
2-deoxygenated
glycosides
bearing
modifiable
boron
groups
could
be
rapidly
made
with
excellent
stereocontrol
exhibit
remarkable
functional
tolerance.
The
synthetic
underscored
late-stage
natural
products
commercial
drugs
as
well
facile
preparation
various
rare
sugars,
bioactive
conjugates,
key
intermediates
prorocentin,
phomonol,
aspergillide
A.
Precision Chemistry,
Год журнала:
2024,
Номер
2(11), С. 587 - 599
Опубликована: Июль 21, 2024
Nonclassical
C-glycosides,
distinguished
by
their
unique
glycosidic
bond
connection
mode,
represent
a
promising
avenue
for
the
development
of
carbohydrate-based
drugs.
However,
accessibility
nonclassical
C-glycosides
hinders
broader
investigations
into
structural
features
and
modes
action.
Herein,
we
present
first
example
Pd-catalyzed
stereospecific
glycosylation
anomeric
stannanes
with
aryl
or
vinyl
halides.
This
method
furnishes
desired
in
good
to
excellent
yields,
while
allowing
exclusive
control
configuration.
Of
significant
note
is
demonstration
generality
practicality
this
C-glycosylation
approach
across
more
than
50
examples,
encompassing
various
protected
unprotected
saccharides,
deoxy
sugars,
oligopeptides,
complex
molecules.
Furthermore,
biological
evaluation
indicates
that
modifications
drug
molecules
can
positively
impact
activity.
Additionally,
extensive
computational
studies
are
conducted
elucidate
rationale
behind
differences
reaction
reactivity,
unveiling
transmetalation
transition
state
containing
silver
(Ag)
within
six-membered
ring.
Given
its
remarkable
controllability,
predictability,
consistently
high
chemical
selectivity
stereospecificity
regarding
carbon
Z/E
configuration,
outlined
study
offers
solution
longstanding
challenge
accessing
stereocontrol.
Angewandte Chemie,
Год журнала:
2023,
Номер
135(38)
Опубликована: Июнь 7, 2023
Abstract
Glycosyl
radical
functionalization
is
one
of
the
central
topics
in
synthetic
carbohydrate
chemistry.
Recent
advances
metal‐catalyzed
cross‐coupling
chemistry
and
metallaphotoredox
catalysis
provided
powerful
platforms
for
glycosyl
diversification.
In
particular,
discovery
new
precursors
conjunction
with
these
advanced
reaction
technologies
have
significantly
expanded
space
compound
synthesis.
this
Review,
we
highlight
most
recent
progress
area
starting
from
2021,
reports
included
will
be
categorized
based
on
different
types
better
clarity.
Organic Letters,
Год журнала:
2024,
Номер
26(7), С. 1332 - 1337
Опубликована: Фев. 8, 2024
We
disclosed
a
Ni/CPA
cocatalyzed
protocol
to
access
diverse
C-acyl
glycosides
under
mild
conditions
with
broad
functional
group
compatibility
through
the
coupling
of
readily
available
glycosyl
bromides
and
carboxylic
esters.
The
potential
application
methodology
was
demonstrated
by
glycosylation
bioactive
molecules
transformation
products
variety
value-added
molecules.
Mechanistic
studies
revealed
that
CPA
might
serve
as
bifunctional
H-bond
catalyst
activate
esters
nickel
catalyst.
We
present
a
versatile
palladium-catalyzed
glycosylation
platform
that
enables
facile
access
to
structurally
diverse
N-O-linked
glycosides
with
constantly
excellent
regio-
and
stereoselectivities.
Importantly,
this
approach
offers
broad
substrate
scope,
low
catalyst
loadings,
outstanding
chemoselectivity,
allowing
for
the
selective
reaction
of
oximes/hydroximic
acids
over
hydroxyl
groups
would
otherwise
pose
challenges
in
conventional
methods.
The
synthetic
utility
method
is
further
exemplified
through
range
transformations
late-stage
modification
bioactive
molecules.
Overall,
our
provides
an
efficient
toolkit
synthesis
glycosides,
which
will
facilitate
their
subsequent
biological
evaluations.
Advanced Synthesis & Catalysis,
Год журнала:
2024,
Номер
366(8), С. 1847 - 1856
Опубликована: Фев. 17, 2024
Abstract
Herein,
we
present
an
approach
for
catalytic
orthogonal
glycosylation
utilizing
earth‐abundant
copper
carbenes.
This
method
operates
under
mild
conditions
and
employs
readily
accessible
starting
materials,
including
benchtop
stable
enynal‐derived
glycosyl
donors,
synthesized
at
the
gram
scale.
The
reaction
accommodates
a
variety
of
acceptors,
primary,
secondary,
tertiary
alcohols.
carbenes
exhibit
remarkable
reactivity
selectivity,
allowing
formation
glycosidic
linkages
with
different
protecting
groups
stereochemical
patterns.
provides
access
to
both
1,2‐
cis
‐
trans
‐glycosidic
linkages.
product
stereoselectivity
is
independent
anomeric
configuration
donor,
which
also
has
widely
used
alkynes
thioglycoside
donors.
An
iterative
synthesis
trisaccharide
further
demonstrates
application
this
reactivity.
