Synthesis of Fluorescent Cyclic Peptides via Gold(I)-Catalyzed Macrocyclization
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(49), С. 26525 - 26531
Опубликована: Ноя. 30, 2023
Rapid
and
efficient
cyclization
methods
that
form
structurally
novel
peptidic
macrocycles
are
of
high
importance
for
medicinal
chemistry.
Herein,
we
report
the
first
gold(I)-catalyzed
macrocyclization
peptide-EBXs
(ethynylbenziodoxolones)
via
C2-Trp
C–H
activation.
This
reaction
was
carried
out
in
presence
protecting
group
free
peptide
sequences
is
enabled
by
a
simple
commercial
gold
catalyst
(AuCl·Me2S).
The
method
displayed
rapid
rate
(within
10
min),
wide
functional
tolerance
(27
unprotected
peptides
were
cyclized),
up
to
86%
isolated
yield.
obtained
highly
conjugated
cyclic
linker,
formed
through
alkynylation,
can
be
directly
applied
live-cell
imaging
as
fluorescent
probe
without
further
attachment
fluorophores.
Язык: Английский
Carboxylate-Catalyzed C-Silylation of Terminal Alkynes
Organic Letters,
Год журнала:
2024,
Номер
26(10), С. 1991 - 1995
Опубликована: Март 1, 2024
A
carboxylate-catalyzed,
metal-free
C-silylation
protocol
for
terminal
alkynes
is
reported
using
a
quaternary
ammonium
pivalate
as
the
catalyst
and
commercially
available
N,O-bis(silyl)acetamides
silylating
agents.
The
reaction
proceeds
under
mild
conditions,
tolerates
range
of
functionalities,
enables
concomitant
O-
or
N-silylation
acidic
OH
NH
groups.
Hammett
ρ
value
+1.4
±
0.1
obtained
para-substituted
2-arylalkynes
consistent
with
proposed
catalytic
cycle
involving
turnover-determining
deprotonation
step.
Язык: Английский
Amino‐ and Alkoxybenziodoxoles: Facile Preparation and Use as Arynophiles
Chemistry - A European Journal,
Год журнала:
2024,
Номер
30(29)
Опубликована: Март 18, 2024
Abstract
We
report
here
on
the
facile
synthesis
of
amino‐
and
alkoxy‐λ
3
‐iodanes
supported
by
a
benziodoxole
(BX)
template
their
use
as
arynophiles.
The
alkoxy‐BX
derivatives
can
be
readily
synthesized
reacting
respective
amines
or
alcohols
with
chlorobenziodoxole
in
presence
suitable
base.
Unlike
previously
known
nitrogen‐
oxygen‐bound
iodane
compounds,
which
have
primarily
been
employed
electrophilic
group
transfer
agents
oxidants,
present
reagents
manifest
themselves
nucleophilic
amino
alkoxy
toward
arynes.
This
reactivity
leads
to
aryne
insertion
into
N−I(III)
O−I(III)
bond
afford
ortho
‐amino‐
‐alkoxy‐arylbenziodoxoles,
compounds
nontrivial
procure
existing
methods.
BX
these
products
exhibits
excellent
leaving
ability,
enabling
diverse
downstream
transformations.
Язык: Английский
Carboxylate catalyzed silylation of alkynes
Опубликована: Дек. 14, 2023
A
carboxylate-catalyzed,
metal-free
C-silylation
protocol
for
terminal
alkynes
is
reported
using
a
quaternary
ammonium
pivalate
as
the
catalyst
and
commercially
available
N,O-bis(silyl)acetamides
silylating
agents.
The
reaction
proceeds
under
mild
conditions,
tolerates
range
of
functionalities,
enables
concomitant
O-
or
N-silylation
acidic
OH
NH
groups.
Hammett
ρ
value
+1.4±0.1
obtained
p-substituted
2-arylalkynes
consistent
with
proposed
catalytic
cycle
involving
turnover-determining
deprotonation
step.
Язык: Английский
Structure-reactivity analysis of novel hypervalent iodine reagents in S-vinylation of thiols
Frontiers in Chemistry,
Год журнала:
2024,
Номер
12
Опубликована: Фев. 29, 2024
The
transition-metal
free
S-vinylation
of
thiophenols
by
vinylbenziodoxolones
(VBX)
constituted
an
important
step
forward
in
hypervalent
iodine-mediated
vinylations,
highlighting
the
difference
to
vinyliodonium
salts
and
that
reaction
outcome
was
influenced
substitution
pattern
benziodoxolone
core.
In
this
study,
we
report
several
new
classes
iodine
vinylation
reagents;
vinylbenziodazolones,
vinylbenziodoxolonimine
vinyliodoxathiole
dioxides.
Their
synthesis,
structural
electronic
properties
are
described
correlated
outcome,
shedding
light
on
some
interesting
facets
these
reagents.
Язык: Английский
Oxidative fluorination with Selectfluor: A convenient procedure for preparing hypervalent iodine(V) fluorides
Beilstein Journal of Organic Chemistry,
Год журнала:
2024,
Номер
20, С. 1785 - 1793
Опубликована: Июль 29, 2024
The
ability
to
investigate
hypervalent
iodine(V)
fluorides
has
been
limited
primarily
by
their
difficult
preparation
traditionally
using
harsh
fluorinating
reagents
such
as
trifluoromethyl
hypofluorite
and
bromine
trifluoride.
Here,
we
report
a
mild
efficient
route
Selectfluor
deliver
in
good
isolated
yields
(72–90%).
Stability
studies
revealed
that
bicyclic
difluoro(aryl)-λ
5
-iodane
6
was
much
more
stable
acetonitrile-
d
3
than
chloroform-
1
,
presumably
due
acetonitrile
coordinating
the
centre
stabilising
it
via
halogen
bonding.
Язык: Английский