Asymmetric phase-transfer catalysis
Nature Reviews Chemistry,
Год журнала:
2024,
Номер
8(11), С. 851 - 869
Опубликована: Окт. 9, 2024
Язык: Английский
Highly Nucleophilic Pyridinamide Anions in Apolar Organic Solvents due to Asymmetric Ion Pair Association
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 24, 2025
Free
ions
in
organic
solvents
of
low
polarity
would
be
valuable
tools
for
the
activation
low-reactivity
substrates.
However,
formation
unreactive
ion
pairs
at
concentrations
relevant
synthesis
has
prevented
success
this
concept
so
far.
On
example
highly
nucleophilic
pyridinamide
phosphonium
salts
dichloromethane,
we
show
that
asymmetric
aggregation
offers
a
solution
to
general
problem.
A
combination
conductivity,
diffusion-ordered
NMR
(DOSY),
and
kinetic
measurements
utilizing
refined
ionic
strength-controlled
benzhydrylium
methodology
enables
unique
insight
into
aggregation/association
state
nucleophilicity
involved
anions.
This
approach
reveals
tetraphenylphosphonium
aggregate
dichloromethane
asymmetrically
form
sandwich-type
cations
anions
together
with
their
free
counterions.
The
exceeds
neutral
reference
nucleophile
9-azajulolidine
(TCAP)
by
up
2
orders
magnitude.
Based
on
these
results,
suggest
might
pathway
boost
reactivity
anionic
nucleophiles.
Язык: Английский
Isothiourea‐Catalyzed Enantioselective Functionalisation of Glycine Schiff Base Aryl Esters via 1,6‐ and 1,4‐Additions
ChemistryEurope,
Год журнала:
2023,
Номер
1(1)
Опубликована: Май 3, 2023
Abstract
The
enantioselective
α‐functionalisation
of
glycine
Schiff
base
aryl
esters
through
isothiourea
catalysis
is
successfully
demonstrated
for
1,6‐additions
to
para‐quinone
methides
(21
examples,
up
95
:
5
dr
and
96
4
er)
1,4‐
additions
methylene
substituted
dicarbonyl
or
disulfonyl
Michael
acceptors
(17
98
2
er).
This
nucleophilic
organocatalysis
approach
gives
access
a
range
α‐functionalised
α‐amino
acid
derivatives
further
transformations
the
activated
ester
group
provide
straightforward
entry
advanced
amino
acid‐based
esters,
amides
thioesters.
Язык: Английский
Recent advances in organocatalytic enantioselective syntheses of β-fluoroamine compounds
Molecular Catalysis,
Год журнала:
2025,
Номер
576, С. 114944 - 114944
Опубликована: Фев. 26, 2025
Язык: Английский
Recent Advances in Catalytic Approaches for Pyrano[2,3‐c]Pyrazole Synthesis: Green and Sustainable Perspectives
ChemistrySelect,
Год журнала:
2025,
Номер
10(12)
Опубликована: Март 1, 2025
Abstract
This
review
provides
a
detailed
look
at
the
methods
used
to
create
pyrano[2,3‐c]pyrazole
derivatives
over
past
ten
years,
with
focus
on
various
catalytic
techniques.
The
highlights
progress
in
green
chemistry,
showing
how
catalysts
such
as
homogeneous,
heterogeneous,
and
nanoparticle
types
have
been
used.
It
also
discusses
new
approaches
like
microwave‐assisted
catalyst‐free
synthesis.
evaluates
effectiveness
of
different
based
reaction
efficiency,
yield,
sustainability.
Furthermore,
it
explores
eco‐friendly
options
bio‐catalysts
ionic
liquid
catalysts,
which
offer
scalable
environmentally‐friendly
for
producing
these
important
compounds.
Pyrano[2,3‐c]pyrazoles
were
chosen
their
significant
potential
pharmaceuticals
industry.
emphasizes
sustainable
are
becoming
more
modern
particularly
due
reusability
lower
environmental
impact,
making
them
ideal
industrial
applications.
Язык: Английский
Towards an asymmetric β-selective addition of azlactones to allenoates
Beilstein Journal of Organic Chemistry,
Год журнала:
2024,
Номер
20, С. 1504 - 1509
Опубликована: Июль 4, 2024
We
herein
report
the
asymmetric
organocatalytic
addition
of
azlactones
to
allenoates.
Upon
using
chiral
quaternary
ammonium
salt
catalysts,
i.e.,
Maruoka’s
binaphthyl-based
spirocyclic
salts,
various
allenoates
proceeds
in
a
β-selective
manner
with
moderate
levels
enantioselectivities
(up
83:17
er).
Furthermore,
obtained
products
can
be
successfully
engaged
nucleophilic
ring
opening
reactions,
thus
giving
highly
functionalized
α-amino
acid
derivatives.
Язык: Английский
Chiral Quaternary Ammonium Salt‐Catalyzed Enantioselective Addition Reactions of Hydantoins
Helvetica Chimica Acta,
Год журнала:
2023,
Номер
107(3)
Опубликована: Дек. 29, 2023
Abstract
We
herein
report
a
protocol
for
the
asymmetric
1,4‐addition
of
hydantoins
to
various
Michael
acceptors
by
utilizing
Cinchona
alkaloid‐based
chiral
quaternary
ammonium
salt
catalysts.
Various
products
were
obtained
with
moderate
good
enantioselectivities
and
accompanying
computational
investigations
helped
identify
key
interactions
responsible
observed
selectivity.
DFT
calculations
along
non‐covalent
interaction
plots
reveal
presence
numerous
stabilizing
non‐classical
hydrogen
bonding
other
between
hydantoin
molecule
in
C−C
bond
forming
transition
states
leading
formation
products.
In
addition,
first
proof‐of‐concept
an
analogous
a‐sulfanylation
reaction,
albeit
poor
selectivity,
is
reported
as
well.
Язык: Английский