European Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 16, 2024
Abstract
A
squaramide
moiety
introduced
at
the
C‐4
position
of
proline
produced
an
organocatalyst
that
promoted
direct
asymmetric
aldol
addition
in
presence
water.
variety
adducts,
majorly
from
reaction
cyclohexanone
with
aldehydes,
were
obtained
yields
generally
range
53–99
%,
accompanied
by
71–99
%
ee
and
83
:
17
to
>99
1
diastereomeric
ratios.
An
desymmetrization
4‐alkyl
cyclohexanones
was
also
achieved
using
transformation.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(5), P. 3065 - 3074
Published: Jan. 28, 2024
Chiral
1-pyrrolines
containing
a
nitrile
motif
serve
as
crucial
structural
scaffolds
in
biologically
active
molecules
and
exhibit
diversity
building
blocks
owing
to
their
valuable
functional
groups;
however,
the
asymmetric
synthesis
of
such
compounds
remains
largely
unexplored.
Herein,
we
present
an
enantio-
diastereoselective
method
for
α-chiral
nitrile-containing
1-pyrroline
derivatives
bearing
vicinal
stereocenters
through
design
introduction
chiral
cyclopropenimine-based
bifunctional
catalysts
featuring
thiourea
moiety.
This
entails
highly
stereoselective
conjugate
addition
α-iminonitriles
wide
array
enones,
followed
by
cyclocondensation,
thereby
affording
series
cyanopyrroline
derivatives,
some
which
contain
all-carbon
quaternary
centers.
Moreover,
demonstrate
synthetic
utility
this
strategy
performing
gram-scale
reaction
with
1%
catalyst
loading,
along
variety
chemoselective
transformations
product,
including
vildagliptin
analogue.
Finally,
showcase
selective
all
four
stereoisomers
products
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Aug. 5, 2024
Asymmetric
catalysis
for
enantioselective
intramolecular
hydroamination
of
alkenes
is
a
critical
method
in
the
construction
enantioenriched
nitrogen-containing
rings,
often
prevalent
biologically
active
compounds
and
natural
products.
Herein,
we
demonstrate
facile
synthesis
chiral
pyrrolidine,
piperidine,
indoline
moieties,
using
manganese
(II)
aprotic
cyclic
urea
catalyst.
The
ligand
hinders
inversion
N
atom
effectively
discriminate
between
enantiomers
substrates.
High-resolution
mass
spectrometry,
deuterium
labeling
experiments,
molecular
orbital
energy
analysis
clearly
reveal
intermediates
mechanism
transformation.
As
key
step,
oxygen
coordination
by
presents
robust
control
over
asymmetric
intra-HA
reaction
through
involvement
convergent
assembly
two
vital
(Mn-N
C-Mn-Br),
providing
access
to
amine
systems
high
yields
with
excellent
enantioselectivity.
Nitrogen-containing
rings
containing
carbon
centers
are
staple
bioactive
molecules
products
interest,
synthetic
methodologies
their
development
continual
focus
organic
chemists.
Here,
authors
disclose
protocol
saturated
azacycles,
via
alkenes,
manganese.
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(7), P. 1472 - 1477
Published: Feb. 13, 2024
A
highly
efficient
enantioselective
[4
+
2]
cycloaddition
of
2-amino-β-nitrostyrenes
with
cyclic
N-sulfonyl
ketimines
has
been
developed.
This
reaction
utilizes
an
organocatalytic
approach,
employing
a
multiple-hydrogen-bonding
bifunctional
squaramide-based
catalyst.
The
process
allows
for
the
precise
synthesis
chiral
polycyclic
benzosultams,
showcasing
intricate
structures
that
incorporate
quaternary
centers.
Noteworthy
outcomes
this
method
include
high
yields
excellent
enantioselectivities
and
diastereoselectivities
(up
to
97%
yield,
96%
ee,
>20:1
dr).
Organic Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 25, 2025
A
highly
efficient
enantioselective
Michael
addition
of
cyclic
N-sulfonylimines
with
nitroalkenes
has
been
developed,
utilizing
a
bifunctional
squaramide
catalyst.
This
approach
achieves
remarkable
results,
delivering
products
high
yields
and
outstanding
stereoselectivities,
reaching
up
to
97%
yield,
>20:1
dr,
>99%
ee.
Furthermore,
an
asymmetric
tandem
reaction
2-nitroallylic
acetates
established.
innovative
methodology
involves
Michael/intramolecular
aza-Michael
cascade,
leading
the
formation
enantioenriched
benzosultam-fused
tricyclic
compounds
excellent
stereoselectivities
(up
dr
ee).
Inorganic Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 5, 2025
The
Brønsted
acid
catalysis
is
widely
regarded
as
one
of
the
most
effective
methods
for
activating
inert
substrates
and
enabling
unique
reactivity.
In
this
work,
we
introduce
first
example
H-bond-assisted
chalcogen
exchange
between
arsine
oxides
phosphine
selenides
under
mild
conditions,
providing
a
powerful
approach
to
synthesis
selenides.
reaction
proceeds
successfully
in
both
protic
aprotic
solvents
accelerated
by
presence
any
nonaqueous
acid.
This
newly
discovered
tested
various
R3AsO
(R
=
Ph,
Et,
nBu,
iPr)
R3PSe
Me,
tBu)
overall
demonstrates
high
conversion,
although
use
reagents
with
bulky
substituents
significantly
hinders
its
efficiency.
mechanism
involves
formation
four-membered
cyclic
transition
state,
which
requires
overcoming
steric
electrostatic
repulsion,
well
significant
distortion
reagents'
tetrahedral
geometry.
Hydrogen
bonding
As═O
fragment
helps
reduce
repulsion
P═Se
groups,
making
intermediate
more
favorable.
Advanced Science,
Journal Year:
2024,
Volume and Issue:
11(28)
Published: May 15, 2024
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.
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
89(12), P. 8691 - 8705
Published: June 10, 2024
Organocatalyzed
diastereo-
and
enantioselective
[3
+
2]
cycloaddition
reactions
of
donor-acceptor
(D-A)
cyclopropanes
with
isatin-derived
ketimines
are
presented.
Different
from
well-developed
Lewis
acid
activation
protocols
which
promote
the
reactivity
D-A
through
coordinating
to
acceptor
group,
in
this
reaction,
dicyanocyclopropylmethyl
ketones
can
be
activated
nucleophilic
donor
group
by
using
dihydroquinine-derived
squaramide
as
Brønsted
base
catalyst.
The
reaction
affords
functionalized
spiro[oxindole-3,2'-pyrrolidines]
two
nonadjacent
tetra-
tri-substituted
stereocenters
83-99%
yields,
moderate
excellent
diastereoselectivities
(up
>20:1
diastereomeric
ratio
(dr)),
enantioselectivities
>99%
enantiomeric
excess
(ee))
under
mild
conditions.
Molecules,
Journal Year:
2023,
Volume and Issue:
28(8), P. 3529 - 3529
Published: April 17, 2023
Protic
pyrazoles
(N-unsubstituted
pyrazoles)
have
been
versatile
ligands
in
various
fields,
such
as
materials
chemistry
and
homogeneous
catalysis,
owing
to
their
proton-responsive
nature.
This
review
provides
an
overview
of
the
reactivities
protic
pyrazole
complexes.
The
coordination
pincer-type
2,6-bis(1H-pyrazol-3-yl)pyridines
is
first
surveyed
a
class
compounds
for
which
significant
advances
made
last
decade.
stoichiometric
complexes
with
inorganic
nitrogenous
are
then
described,
possibly
relates
nitrogen
cycle
part
this
article
devoted
outlining
catalytic
application
complexes,
emphasizing
mechanistic
aspect.
role
NH
group
ligand
resulting
metal–ligand
cooperation
these
transformations
discussed.
