Abstract
Axially
chiral
furan‐based
scaffolds
have
been
recognized
as
a
class
of
important
five‐membered
heteroaryl
atropisomers,
and
developing
catalytic
atroposelective
reactions
for
constructing
this
is
highly
desirable.
However,
the
construction
such
rather
underdeveloped
due
to
existence
great
challenges
remote
ortho
‐substituents
weak
configurational
stability.
To
overcome
these
challenges,
synthetic
chemists
recently
paid
attention
research
field,
number
axially
constructed
via
using
different
strategies.
This
concept
summarized
advances
in
field
pointed
out
remaining
which
will
promote
further
development
emerging
field.
An
efficient
catalytic
asymmetric
olefin
isomerization
of
axially
chiral
methylene
dihydrofuran-benzimidazoles
via
kinetic
resolution
is
reported.
Under
mild
phase-transfer
catalysis,
furan-benzimidazole
compounds
and
recovered
were
obtained
in
high
ee.
The
combination
the
TBD-catalyzed
provided
access
to
both
enantiomers
furan-benzimidazoles.
Deuterium-labeling
experiments
reveal
intramolecular
[1,3]-H
transfer
mechanism.
utility
this
method
was
demonstrated
by
scale-up
synthesis
functionalization
products.
European Journal of Organic Chemistry,
Год журнала:
2024,
Номер
27(23)
Опубликована: Апрель 10, 2024
Abstract
The
catalytic
asymmetric
reaction
of
5‐aminopyrazoles
with
naphthoquinone
esters
has
been
established.
A
wide
range
unprecedented
axially
chiral
naphthylpyrazole
derivatives
(29
examples)
have
synthesized
in
moderate
to
excellent
yields
(up
99
%
yield)
enantioselectivities
ee)
by
utilizing
phosphoric
acid
as
a
catalyst.
This
protocol
features
mild
conditions,
broad
substrate
scope,
good
scalability
and
facile
derivatization.
Moreover,
preliminary
mechanistic
investigation
was
conducted
elucidate
the
mechanism.
Organic Letters,
Год журнала:
2024,
Номер
26(3), С. 681 - 686
Опубликована: Янв. 17, 2024
This
study
presents
the
atroposelective
alkylation
of
2-arylindoles
catalyzed
by
a
substituted
cinchonium
salt
as
phase-transfer
catalyst.
Under
optimized
reaction
conditions,
various
substrates
are
employed
to
yield
products
with
high
enantioselectivity.
The
presence
an
ortho-nitro
group
at
aromatic
ring
is
essential
for
atroposelectivity,
because
it
facilitates
favorable
interactions
between
catalyst
and
substrate.
origin
enantioselectivity
reveals
π–π
both
enantiomers
unfavorable
steric
strains
undesired
enantiomers.
Abstract
Axially
chiral
thioethers
and
sulfoxides
emerge
as
two
pivotal
classes
of
ligands
organocatalysts,
which
have
remarkable
features
in
the
stereoinduction
various
asymmetric
transformations.
However,
lack
easy
methods
to
access
such
molecules
with
diverse
structures
has
hampered
their
broader
utilization.
Herein,
an
oxidative
kinetic
resolution
for
sulfides
using
a
bifunctional
squaramide
catalyst
cumene
hydroperoxide
terminal
oxidant
is
established.
This
approach
provides
variety
axially
well
bearing
both
axial
central
chirality,
excellent
diastereo‐
enantioselectivities.
catalytic
system
also
successfully
extends
benzothiophene‐based
sulfides.
Preliminary
mechanism
investigation
indicates
that
multiple
hydrogen
bonding
interactions
between
substrates
play
crucial
role
determining
enantioselectivity
reactivity.
Abstract
Axially
chiral
furan‐based
scaffolds
have
been
recognized
as
a
class
of
important
five‐membered
heteroaryl
atropisomers,
and
developing
catalytic
atroposelective
reactions
for
constructing
this
is
highly
desirable.
However,
the
construction
such
rather
underdeveloped
due
to
existence
great
challenges
remote
ortho
‐substituents
weak
configurational
stability.
To
overcome
these
challenges,
synthetic
chemists
recently
paid
attention
research
field,
number
axially
constructed
via
using
different
strategies.
This
concept
summarized
advances
in
field
pointed
out
remaining
which
will
promote
further
development
emerging
field.
