Herein,
we
report
a
DMAP-catalyzed
[4
+
2]
annulation
reaction
of
hex-5-en-2-ynoates
1
with
electron-poor
alkenes
2,
which
affords
exocyclic
olefinic
cyclohexenes
3
in
good
yields
and
excellent
regio-,
diastereo-,
E/Z
selectivities.
Distinguished
from
previous
allenoate-
or
alkynoate-based
substrates,
use
the
β-
ε-carbons
for
bond
formation,
presenting
new
regiodivergent
C4
synthons
Lewis
base-catalyzed
annulations.
Chemical Science,
Год журнала:
2024,
Номер
15(29), С. 11515 - 11520
Опубликована: Янв. 1, 2024
Organocatalytic
annulations
between
allenes
and
bisnucleophiles
represent
one
of
the
most
convenient
routes
to
various
carbocycles
heterocycles.
However,
examples
are
limited
formation
five-
six-membered
rings,
probably
owing
relatively
easy
handling
short-chained
biselectrophiles.
Here
we
report
long-chained
α-allyl
allenoate-derived
1,6-biselectrophiles
for
first
time,
enabling
a
phosphine
catalyzed
[6
+
1]
annulation
with
readily
available
1,1-bisnucleophilic
reagents.
The
reaction
proceeds
In
this
work,
we
developed
a
phosphine-catalyzed
cascade
lactonization/[2
+
1]
annulation
reaction
between
vinyl
oxiranes
and
sulfonium
compounds
for
the
highly
diastereoselective
construction
of
spiro-2(3H)-furanone
skeletons.
The
cycloaddition
proceeds
via
2(5H)-furanone
phosphonium
intermediate,
introducing
an
oxygen-containing
active
intermediate
phosphine
catalysis.
These
findings
highlight
significant
potential
harnessing
as
versatile
synthons
constructing
spirocyclic
through
simultaneous
multicyclic
skeleton
formation.
Synthesis,
Год журнала:
2024,
Номер
56(16), С. 2581 - 2587
Опубликована: Апрель 30, 2024
Abstract
Unstable
tetra(methoxycarbonyl)cyclopentadienone
was
investigated
in
the
synthesis
of
electron-deficient
cycloheptatrienes
via
[4+2]-cycloaddition/cycloelimination
reaction
with
cyclopropenes.
The
use
its
stable
dimer
did
not
afford
product
although
similar
reactions
alkynes
have
been
reported.
Quantum
chemical
calculation
revealed
that
cyclopentadienone
is
generated
from
and
proceeds
a
more
complicated
cycloelimination/cycloaddition/cycloelimination
cascade.
However,
formation
found
favorable
over
dimer.
Therefore,
trapping
upon
successful
to
give
five
ester
groups.
methyl
coumalate
as
four-electron
component
cyclopropenes
containing
only
one
group
two
groups
product.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(22), С. 16711 - 16720
Опубликована: Окт. 31, 2024
A
phosphine-catalyzed
[4
+
1]
annulation
of
β'-acetoxy
allenoate
with
α-alkylidene
succinimides
is
described.
This
method
demonstrates
the
nucleophilic
dialkylation
and
cyclization
succinimides,
resulting
in
formation
functionalized
spirosuccinimide
derivatives.
The
reaction
exhibits
a
wide
substrate
scope
yields
ranging
from
moderate
to
excellent
under
optimized
conditions.
In
addition,
biological
evaluation
indicates
that
cycloadduct
3u
presents
satisfied
inhibitory
activities
for
three
human
cancer
cell
lines
(HCT116,
A549,
HepG2).
ACS Catalysis,
Год журнала:
2024,
Номер
14(21), С. 16105 - 16114
Опубликована: Окт. 17, 2024
We
introduce
a
phosphine-catalyzed
cycloaddition
involving
unprecedented
long-range
intramolecular
proton
transfer,
facilitating
the
synthesis
of
nine-membered
heterocycles,
which
are
privileged
structures
in
natural
products,
as
well
potent
pharmacophores.
Experimental
and
computational
studies
revealed
that
enamide
tether
N-aromatic
zwitterion
directly
enables
regioselective
transfer
to
proceed
independently
outer-sphere
shuttling.
This
understanding
selective
has
led
improved
efficiency
regioselectivity
desired
1,9-proton
reaction
under
anhydrous
conditions,
thereby
advancing
development
higher-order
reactions.
Further
stereoselective
contraction
synthesized
cyclic
compounds
using
3-aza-Cope
rearrangement
demonstrates
synthetic
versatility
our
approach.
The
findings
this
study
not
only
advance
general
mechanism
but
also
broaden
its
practical
utility
various
chemical
fields.
Organic Letters,
Год журнала:
2024,
Номер
26(36), С. 7495 - 7500
Опубликована: Сен. 5, 2024
A
protocol
for
the
construction
of
cycloheptatrienes
has
been
developed.
4-(Dimethylamino)pyridine
(DMAP)
was
found
to
be
an
efficient
catalyst
promote
[4
+
3]
annulation
between
coumalates
and
γ-alkyl-substituted
allenoate
or
γ-aryl-3-butynoates
deliver
a
variety
in
moderate
good
yield
with
excellent
chemoselectivity.
The
asymmetric
version
this
also
realized
by
using
bifunctional
phosphine
provide
chiral
products
32-97%
ee
29-64%
yield.
