Abstract
A
squaramide‐catalyzed
asymmetric
Michael/cyclization
tandem
reaction
between
3‐hydroxychromenones
and
isatylidenemalononitriles
was
developed.
Using
this
strategy,
a
wide
scope
of
spiro[indoline‐3,4′‐pyrano[3,2‐b]chromene]
derivatives,
which
combined
chromone,
pyran,
indolone
in
one
molecule,
could
be
obtained
moderate
to
excellent
yields
(up
94
%)
with
enantioselectivities
95
%
ee).
In
addition,
the
scaled‐up
experiment
also
confirmed
synthetic
practicality
strategy.
The Journal of Organic Chemistry,
Год журнала:
2020,
Номер
86(2), С. 1712 - 1720
Опубликована: Дек. 30, 2020
In
the
presence
of
chiral
Pd(0)/ligand
complex,
vinyl
benzoxazinanones
underwent
[4+2]
cycloaddition
with
alkylidene
pyrazolones
smoothly
and
delivered
spiropyrazolones
in
reasonable
yields,
diastereoselectivities,
eneantioselectivities
(up
to
>99%
yield,
>99:1
dr
99%
ee).
The
absolute
configuration
obtained
was
unambiguously
characterized
use
X-ray
single-crystal
structure
analysis.
Moreover,
reaction
mechanism
assumed
interpret
formation
target
compounds.
Synthesis,
Год журнала:
2020,
Номер
53(02), С. 215 - 237
Опубликована: Окт. 8, 2020
Abstract
Pyrazolone
[2,4-dihydro-3H-pyrazol-4-one]
represents
one
of
the
most
important
five-membered
nitrogen
heterocycles
which
is
present
in
numerous
pharmaceutical
drugs
and
molecules
with
biological
activity.
Recently,
many
catalytic
methodologies
for
asymmetric
synthesis
chiral
pyrazolones
have
been
established
great
success,
specially,
bearing
a
tetrasubstituted
stereocenter
at
C-4.
This
review
summarizes
these
excellent
research
studies
since
2018,
including
representative
examples
some
mechanistic
pathways
explaining
observed
stereochemistry.
1
Introduction
2
Catalytic
Enantioselective
Synthesis
Chiral
Pyrazolones
Full
Carbon
Tetrasubstituted
Stereocenter
C-4
3
Quaternary
Heteroatom
4
Spiropyrazolones
5
Conclusion
Organic Chemistry Frontiers,
Год журнала:
2020,
Номер
7(5), С. 796 - 809
Опубликована: Янв. 1, 2020
Organo-catalyzed
tandem
reaction
between
β,γ-unsaturated
α-ketoesters
and
α-arylidene
pyrazolinones
was
developed,
it
provided
chiral
bi-spirocyclic
pyrazolone
oxindole
derivatives
in
high
yields
with
good
to
excellent
stereoselectivity.
The Journal of Organic Chemistry,
Год журнала:
2020,
Номер
85(12), С. 7793 - 7802
Опубликована: Май 29, 2020
Based
on
a
novel
umpolung
strategy,
an
efficient
and
highly
enantioselective
cascade
aldol/cyclization/tautomerization
of
the
2-(2-oxoindolin-3-yl)malononitrile
to
active
carbonyl
compounds
with
excellent
diastereo-
enantioselectivity
has
been
developed.
Also,
various
enantio-enriched
multifunctional
dispiro[2-amino-4,5-dihydrofuran-3-carbonitrile]bisoxindoles
adjacent
spiro-stereocenters
were
conveniently
obtained
by
this
methodology.
easily
transformed
into
structurally
complex
molecules
without
any
effect
enantioselectivity.
Asian Journal of Organic Chemistry,
Год журнала:
2021,
Номер
10(6), С. 1345 - 1376
Опубликована: Апрель 19, 2021
Abstract
Chiral
analogues
of
squaramides
have
been
fruitful
in
organocatalyzed
asymmetric
reactions
over
last
decade.
Alongside
other
H‐bonding
catalysts
like
ureas,
thioureas:
proved
to
be
efficient
for
the
formation
acyclic
and
cyclic
chiral
molecules.
A
wide
range
molecules
bearing
multiple
functionalities
stereocenters
synthesized
by
using
several
bifunctional
as
catalysts.
These
perform
base
utilizing
basic
N
atom
their
extension
help
stereoinduction
forming
H‐bonds
with
suitable
H‐bond
acceptors.
The
present
review
focuses
on
assembling
recent
progresses
synthesis
five
six
membered
rings
promoted
squaramides.
handful
articles
published
research
groups
documenting
construction
five‐
six‐membered
part
interesting
complex
molecular
architectures.
Different
methodologies
conventional
formal
cycloadditions
or
cascade
engineered
through
assistance
fabricate
carbo‐
heterocycles.
This
also
includes
dual
cooperative
catalytic
system
which
squaramide
is
one
The Journal of Organic Chemistry,
Год журнала:
2022,
Номер
87(16), С. 11048 - 11062
Опубликована: Авг. 3, 2022
Spiroannulation
reactions
are
fundamental
and
invaluable
for
the
synthesis
of
spirocyclic
compounds.
Presented
herein
novel
cascade
aryl
azomethine
imines
with
cyclic
diazo
compounds
leading
to
formation
dihydrophthalazine
derivatives.
Based
on
experimental
mechanistic
studies,
title
products
is
believed
go
through
imine-assisted
cylcometalation,
Rh-carbene
dediazonization,
migratory
insertion
followed
by
reductive
elimination
imine
ring
opening.
Control
experiments
revealed
that
air
acts
as
an
effective
sustainable
co-oxidant
facilitate
reaction.
In
general,
this
concise
unprecedented
derivatives
has
advantages
such
easily
accessible
substrates,
good
functional
group
compatibility,
mild
reaction
conditions,
high
efficiency
selectivity,
excellent
atom-economy.
addition,
value
protocol
underlined
its
ready
scalability
divergent
derivation
products.
Organic Letters,
Год журнала:
2020,
Номер
22(24), С. 9539 - 9544
Опубликована: Дек. 2, 2020
An
asymmetric
[3
+
2]-cycloaddition
reaction
of
α,β-unsaturated
2-acyl
imidazoles
with
spirovinylcyclopropanyl-2-oxindoles
catalyzed
synergistically
by
an
achiral
palladium(0)
catalyst
and
a
chiral-at-metal
rhodium(III)
complex
has
been
developed.
A
series
biologically
important
3-spirocyclopentane-2-oxindoles
four
contiguous
stereocenters
were
synthesized
in
high
yields
(up
to
99%)
excellent
stereoselectivities
99%
ee,
20:1
dr).
Advanced Synthesis & Catalysis,
Год журнала:
2021,
Номер
363(13), С. 3283 - 3289
Опубликована: Апрель 23, 2021
Abstract
Carbon
bisnucleophiles
are
important
building
blocks
in
organic
synthesis
and
have
widespread
applications
the
construction
of
carbocyclic
compounds.
Among
them,
1,2‐carbon
bisnucleophile
has
been
much
less
explored.
Herein,
we
developed
a
[2+3]
annulation
2‐(2‐oxoindolin‐3‐yl)malononitrile
with
2‐nitroallylic
acetates,
where
served
as
new
type
bisnucleophile.
Remarkably,
reaction
exhibits
exclusive
chemo‐
regioselectivity.
A
Michael
addition/S
N
2
mechanism
was
proposed
to
avoid
“anti‐Baldwin”
cyclization.
This
stereoselective
strategy
provides
facile
synthetic
route
for
series
spirocyclopentane
oxindole
derivatives
containing
three
stereogenic
centers.
magnified
image
The Journal of Organic Chemistry,
Год журнала:
2021,
Номер
86(18), С. 13082 - 13091
Опубликована: Авг. 27, 2021
The
first
organocatalytic
asymmetric
synthesis
of
spirooxindole
embedded
oxazolidines
has
been
developed
via
a
domino
reaction
involving
hemiaminal
formation,
followed
by
an
unprecedented
aza-Michael
between
isatin
derived
N-Boc
ketimines
and
γ-hydroxy
enones.
A
quinine
bifunctional
squaramide
catalyst
was
found
to
be
efficient
for
this
reaction,
the
products
were
obtained
in
good
diastereoselectivity
with
high
enantioselectivity.
