Chemistry - A European Journal,
Год журнала:
2024,
Номер
30(48)
Опубликована: Авг. 2, 2024
Abstract
The
cooperative
Lewis
and
Brønsted
acid
catalysis
makes
convergent
synthesis
of
3(2
H
)‐furanones
through
a
three‐component
coupling
1,3‐diynes,
alkyl
glyoxylates
water.
Control
experiments
support
that
acid‐catalyzed
highly
chemo‐,
regio‐
stereoselective
alkyne‐carbonyl
metathesis
1,3‐diynes
might
be
the
initial
step
this
multicomponent
annulation.
Further
chemo‐
regioselective
hydration
product
subsequent
oxa‐Michael
addition
promoted
by
results
in
formation
two
C−O
bonds
five‐membered
oxygen
heterocycle.
One-carbon
ring
expansion
reaction
of
N-heterocycles
has
gained
particular
attention
in
the
past
decade
because
this
method
allows
for
conversion
readily
available
into
potentially
useful
complex
ring-expanded
N-heterocycles,
which
are
inaccessible
by
traditional
methods.
However,
catalytic
asymmetric
variant
been
rarely
reported
to
date.
Herein,
we
disclose
an
enantioselective
one-carbon
through
chiral
copper-catalyzed
diyne
cyclization,
leading
practical,
atom-economic
and
divergent
assembly
array
valuable
bearing
a
quaternary
stereocenter
generally
good
excellent
yields
with
enantioselectivities
(up
>99%
ee).
This
protocol
represents
first
example
based
on
alkynes.
Herein,
we
describe
an
efficient
copper-catalyzed
cyclization
of
triynes
via
vinyl
cation
intermediates.
The
reaction
leads
to
the
practical
and
atom-economical
synthesis
valuable
polycyclic
pyrroles
by
constructing
three
new
rings
in
one
step
under
mild
conditions.
proposed
mechanism
shows
ordered
regioselective
alkynes.
Moreover,
possibility
such
asymmetric
triyne
also
emerges.
Nature Communications,
Год журнала:
2024,
Номер
15(1)
Опубликована: Окт. 25, 2024
The
asymmetric
Büchner
reaction
and
related
arene
cyclopropanations
represent
one
type
of
the
powerful
methods
for
enantioselective
dearomatization.
However,
examples
reactions
via
a
non-diazo
approach
are
quite
scarce,
cyclopropanation
based
on
alkynes
has
not
been
reported.
Herein,
we
disclose
an
by
copper-catalyzed
controllable
cyclization
N-propargyl
ynamides
vinyl
cation
intermediates,
leading
to
chiral
tricycle-fused
cycloheptatrienes
benzonorcaradienes
in
high
yields
enantioselectivities.
Importantly,
this
protocol
represents
cations.
ACS Catalysis,
Год журнала:
2023,
Номер
13(13), С. 8803 - 8812
Опубликована: Июнь 19, 2023
Herein,
an
organocatalytic
enantioselective
desymmetrizing
hydroalkoxylation
of
1,4-
and
1,8-diynes
is
disclosed,
which
represents
a
unique
chiral
Brønsted
acid-catalyzed
desymmetrization
diynes.
This
protocol
provides
facile
practical
access
to
enantioenriched
1,3-diaminopropanol
derivatives
γ-butyrolactones
with
wide
substrate
scope
generally
high
enantioselectivities.
Besides,
the
backbones
these
products
constitute
structural
core
numerous
bioactive
molecules,
they
can
serve
as
valuable
precursors
for
expeditious
assembly
versatile
N-
O-heterocycles.
Moreover,
control
experiments
theoretical
calculations
are
employed
confirm
mechanistic
rationale
elucidate
origin
enantioinduction.
Here,
an
Ir/Zn-cocatalyzed
atroposelective
[2+2+2]
cycloaddition
of
1,6-diynes
and
ynamines
was
developed,
forging
various
functionalized
C─N
axially
chiral
indoles
pyrroles
in
generally
good
to
excellent
yields
(up
99%),
chemoselectivities,
high
enantioselectivities
98%
enantiomeric
excess)
with
wide
substrate
scope.
This
cocatalyzed
strategy
not
only
provided
alternative
promising
reliable
way
for
asymmetric
alkyne
cyclotrimerization
easy
handle
but
also
settled
the
issues
previous
[Rh(COD)2]BF4-catalyzed
system
on
construction
axial
chirality
such
as
complex
operations,
limited
scope,
low
efficiency.
In
addition,
control
experiments
theoretical
calculations
disclosed
that
Zn(OTf)2
markedly
reduced
barrier
migration
insertion
significantly
increase
reaction
efficiency,
which
distinctly
different
from
work
Lewis
acid
improving
yield
through
accelerating
oxidative
addition
reductive
elimination.
Communications Chemistry,
Год журнала:
2023,
Номер
6(1)
Опубликована: Сен. 12, 2023
Abstract
One-carbon
homologation
reactions
based
on
one-carbon
insertion
into
the
N−O
bond
of
heterocycles
have
received
tremendous
interest
over
past
decades.
However,
these
protocols
to
rely
use
hazardous
and
not
easily
accessible
diazo
compounds
as
precursors,
examples
relevant
asymmetric
catalysis
been
reported.
Here
we
show
that
a
copper-catalyzed
intermolecular
formal
(5
+
1)
annulation
1,5-diynes
with
1,2,5-oxadiazoles
involving
heterocyclic
via
non-diazo
approach.
This
method
enables
practical
atom-economic
synthesis
valuable
pyrrole-substituted
oxadiazines
in
generally
moderate
good
yields
under
mild
reaction
conditions.
In
addition,
possibility
such
an
also
emerges.
Synthesis,
Год журнала:
2024,
Номер
56(15), С. 2316 - 2328
Опубликована: Янв. 9, 2024
Abstract
The
atroposelective
transformation
of
alkynes
is
an
efficient
protocol
for
the
assembly
axially
chiral
compounds.
Benefitting
from
rapid
development
organocatalysts,
organocatalytic
reactions
have
been
extensively
studied
over
past
decades.
An
array
catalysts,
including
Brønsted
acid
secondary
amine
N-heterocyclic
carbene
(NHC)
thiourea
catalysts
and
N-squaramide
are
employed
in
enantioselective
different
alkynes.
This
short
review
summarizes
recent
advances
on
according
to
type
alkyne
substrate.
reaction
mechanisms,
modes
enantiocontrol,
product
diversity
applications
highlighted.
1
Introduction
2
Electron-Rich
Aryl
Alkynes
3
Electron-Deficient
4
Other
Types
5
Conclusion
Outlook
Chemistry - A European Journal,
Год журнала:
2024,
Номер
30(41)
Опубликована: Май 23, 2024
Transition
metal-catalyzed
epoxidation
of
carbonyl
compounds
through
ylides
represents
a
highly
effective
method
for
synthesizing
diverse
range
valuable
epoxides.
This
review
offers
an
in-depth
overview
the
latest
developments
in
inter-
and
intramolecular
reactions
involving
metal
carbenes
compounds,
encompassing
both
racemic
to
enantioselective
transformations.
These
catalytic
epoxidations
are
reviewed
by
highlighting
their
product
selectivity,
diversity
applicability,
related
mechanistic
rationale
is
showcased
where
possible.
