The Journal of Organic Chemistry,
Год журнала:
2023,
Номер
88(24), С. 16803 - 16816
Опубликована: Дек. 5, 2023
The
visible
light-induced
perfluoroalkyl
(RF)
radical
reactions
on
peracetylglycals
derived
from
hexoses
and
pentoses
(galactal,
glucal,
arabinal,
xylal
derivatives)
were
investigated.
Various
photocatalysts
iodides
(RF–I)
employed
as
sources
of
RF
radicals
with
LEDs
the
irradiation
source.
Particularly
noteworthy
was
use
an
Iridium
photocatalyst,
Ir[dF(CF3)ppy]2(dtbpy))PF6,
which
yielded
two
distinct
product
types
when
applied
to
glucal.
On
one
hand,
2-RF-substituted
glucal
formed,
a
trend
observed
even
utilizing
organic
dyes
photocatalysts.
other
unexpected
addition
product,
namely
1-RF-2-iodo-α-manno-configured
C-glycosyl
derivative,
also
obtained,
result
highly
regioselective
reaction
moiety
into
anomeric
carbon,
followed
by
attachment
iodine
atom
C-2
in
axial
disposition.
This
contrasted
carried
out
2-unsubstituted
glycals,
where
incipient
adds
C-2,
generating
stabilized
1-glycosyl
radical.
photocatalyzed
perfluoroalkylations
peracetyl
glycals
galactose,
arabinose,
xylose
all
afforded
good
yields
expected
vinylic
substitution
reaction.
Mechanistic
studies
revealed
that
derivatives
arise
chain
reaction,
whereas
proceed
inefficient
processes.
Molecules,
Год журнала:
2022,
Номер
27(18), С. 5980 - 5980
Опубликована: Сен. 14, 2022
An
improved
method
to
efficiently
synthesize
2-OH
thioaryl
glycosides
starting
from
corresponding
per-protected
glycals
was
developed,
where
1,2-anhydro
sugars
were
prepared
by
the
oxidation
of
with
oxone,
followed
reaction
crude
crystalline
NaBH4
and
aryl
disulfides.
This
has
been
further
used
in
a
one-pot
glycosyl
donors
having
both
“armed”
“NGP
(neighboring
group
participation)”
effects.
Chinese Journal of Organic Chemistry,
Год журнала:
2022,
Номер
42(5), С. 1537 - 1537
Опубликована: Янв. 1, 2022
An
efficient
electrochemical
oxidative
trifluoromethylation
of
α-oxoketene
dithioacetals
with
CF3SO2Na
is
developed
without
the
usage
transition-metal
catalysts
and
external
oxidants.This
protocol
features
mild
reaction
conditions
wide
functionality
tolerance.Mechanistic
insights
indicate
that
proceeded
via
radical
mechanism.
Organic Chemistry Frontiers,
Год журнала:
2023,
Номер
10(10), С. 2405 - 2415
Опубликована: Янв. 1, 2023
A
general
methodology
featuring
a
trifluoromethyl-directed
1,2-
trans
glycosylation
reaction
as
key
step
has
been
developed
to
give
access
various
2-CF
3
-glycoconjugates,
including
carbohydrate
epitopes,
amino
acids,
and
lipids.
Frontiers in Chemistry,
Год журнала:
2021,
Номер
9
Опубликована: Дек. 23, 2021
Herein,
the
convenient
one-step
electrochemical
bromination
of
glycals
using
Bu4NBr
as
brominating
source
under
metal-catalyst-free
and
oxidant-free
reaction
conditions
was
described.
A
series
2-bromoglycals
bearing
different
electron-withdrawing
or
electron-donating
protective
groups
were
successfully
synthesized
in
moderate
to
excellent
yields.
The
coupling
tri-O-benzyl-2-bromogalactal
with
phenylacetylene,
potassium
phenyltrifluoroborate,
a
6-OH
acceptor
achieved
afford
2C-branched
carbohydrates
disaccharides
via
Sonogashira
coupling,
Suzuki
Ferrier
rearrangement
reactions
high
efficiency.
radical
trapping
cyclic
voltammetry
experiments
indicated
that
bromine
radicals
may
be
involved
process.
The Journal of Organic Chemistry,
Год журнала:
2023,
Номер
88(24), С. 16803 - 16816
Опубликована: Дек. 5, 2023
The
visible
light-induced
perfluoroalkyl
(RF)
radical
reactions
on
peracetylglycals
derived
from
hexoses
and
pentoses
(galactal,
glucal,
arabinal,
xylal
derivatives)
were
investigated.
Various
photocatalysts
iodides
(RF–I)
employed
as
sources
of
RF
radicals
with
LEDs
the
irradiation
source.
Particularly
noteworthy
was
use
an
Iridium
photocatalyst,
Ir[dF(CF3)ppy]2(dtbpy))PF6,
which
yielded
two
distinct
product
types
when
applied
to
glucal.
On
one
hand,
2-RF-substituted
glucal
formed,
a
trend
observed
even
utilizing
organic
dyes
photocatalysts.
other
unexpected
addition
product,
namely
1-RF-2-iodo-α-manno-configured
C-glycosyl
derivative,
also
obtained,
result
highly
regioselective
reaction
moiety
into
anomeric
carbon,
followed
by
attachment
iodine
atom
C-2
in
axial
disposition.
This
contrasted
carried
out
2-unsubstituted
glycals,
where
incipient
adds
C-2,
generating
stabilized
1-glycosyl
radical.
photocatalyzed
perfluoroalkylations
peracetyl
glycals
galactose,
arabinose,
xylose
all
afforded
good
yields
expected
vinylic
substitution
reaction.
Mechanistic
studies
revealed
that
derivatives
arise
chain
reaction,
whereas
proceed
inefficient
processes.
