Helvetica Chimica Acta,
Journal Year:
2022,
Volume and Issue:
105(11)
Published: Sept. 20, 2022
We
herein
report
a
protocol
for
the
asymmetric
aldol-initiated
cascade
addition
of
isoxazolidin-5-ones
to
ortho-cyanobenzaldehydes
by
using
Takemoto's
bifunctional
organocatalyst.
This
approach
allows
synthesis
various
novel
β2,2-amino
acid-phthalide
conjugates
with
good
enantio-
and
diastereoselectivities
in
reasonable
yields
further
ring-opening
these
compounds
acyclic
carboxylic
acid
derivatives
was
demonstrated
too.
Advanced Synthesis & Catalysis,
Journal Year:
2021,
Volume and Issue:
363(23), P. 5196 - 5234
Published: Oct. 14, 2021
Abstract
Five‐membered
heterocycles
bearing
an
exocyclic
double
bond
have
been
successfully
used
as
substrates
in
asymmetric
addition
and
cycloaddition
reactions.
Ylidene‐heterocycles
are
attractive
due
to
their
high
functionalization
the
presence
of
electrophilic
conjugated
bound
that
can
participate
nucleophilic
reactions
well
reactions,
which
may
be
triggered
by
formation
aromatic
intermediates
or
products
many
cases.
During
last
decades,
catalytic
methodologies
developed
using
ylidene‐heterocycles
order
synthesize
useful
optically
active
heterocyclic
derivatives.
4‐Ylidene‐pyrazol‐5‐ones,
isoxazolin‐5‐ones,
2,3‐dioxopyrrolidines,
rhodanines,
oxazolidindiones,
Erlenmeyer‐Ploch
azlactones
5‐ylidene‐thiazolones
This
review
collects
powerful
research
where
ylidene‐five‐membered
used.
magnified
image
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
61(42)
Published: July 28, 2022
The
catalytic
allylic
substitution
is
one
of
the
most
important
tools
in
asymmetric
synthesis
to
form
C-C
bonds
an
enantioselective
way.
While
high
efficiency
was
previously
accomplished
terms
enantio-
and
regiocontrol
using
different
catalyst
types,
a
strong
general
limitation
very
pronounced
preference
for
formation
products
with
(E)-configured
C=C
double
bonds.
Herein,
we
report
that
planar
chiral
palladacycle
diastereospecific
reaction
outcome
achieved
isoxazolinones
imidates
as
substrates,
thus
maintaining
bond
geometry
substrates
highly
enantioenriched
products.
DFT
calculations
show
reactions
proceed
via
S
Asymmetric Organocatalysis,
Journal Year:
2022,
Volume and Issue:
unknown, P. 71 - 120
Published: Nov. 18, 2022
Asymmetric
(ion-pairing)
phase-transfer
catalysis
has
emerged
as
a
powerful
concept
within
the
realm
of
asymmetric
(organo)-catalysis
over
course
last
four
decades.
Whereas
early
approaches
mainly
focused
around
use
chiral
ammonium
salt
catalysts
for
control
enolate-type
nucleophiles,
years
have
witnessed
remarkable
diversity
novel
catalyst
motives
and
new
applications,
reaching
beyond
what
was
classically
considered
catalysis.
As
consequence,
strict
mechanistic
classification
whether
reaction
is
really
phase-transfer-catalyzed
process
or
not
also
often
so
easily
possible
anymore,
underscoring
this
field.
Within
chapter,
we
wish
to
highlight
unique
potential
cationic,
anionic,
neutral
(PTCs)
facilitate
challenging
target
transformations
by
discussing
some
the,
in
our
opinion,
most
important
classes
applications
thereof,
with
special
focus
on
recently
introduced
concepts.
Synthesis,
Journal Year:
2022,
Volume and Issue:
55(11), P. 1706 - 1713
Published: Sept. 21, 2022
Abstract
The
enantioselective
addition
of
isoxazolidin-5-ones
to
the
β-carbon
allenoates
has
been
carried
out
by
using
a
novel
spirobiindane-based
quaternary
ammonium
salt
catalyst.
This
protocol,
which
proceeds
under
classical
liquid-solid
phase-transfer
conditions,
gives
access
unprecedented
highly
functionalized
β2,2-amino
acid
derivatives
with
good
enantioselectivities
and
in
high
yields,
further
manipulations
these
products
have
as
well.
Helvetica Chimica Acta,
Journal Year:
2022,
Volume and Issue:
105(11)
Published: Sept. 20, 2022
We
herein
report
a
protocol
for
the
asymmetric
aldol-initiated
cascade
addition
of
isoxazolidin-5-ones
to
ortho-cyanobenzaldehydes
by
using
Takemoto's
bifunctional
organocatalyst.
This
approach
allows
synthesis
various
novel
β2,2-amino
acid-phthalide
conjugates
with
good
enantio-
and
diastereoselectivities
in
reasonable
yields
further
ring-opening
these
compounds
acyclic
carboxylic
acid
derivatives
was
demonstrated
too.
