Organic & Biomolecular Chemistry,
Journal Year:
2023,
Volume and Issue:
21(5), P. 950 - 954
Published: Jan. 1, 2023
In
an
extension
of
our
studies
on
low-temperature
rearrangements
1-alkynyl
ethers,
we
describe
herein
the
[3,3]-sigmatropic
rearrangement
in
situ
formed
propargyl
alkynyl
ethers
to
allenyl
ketenes,
which
furnish
complex
tert-butyl-(2E,4Z)-dienoates
2
good
yields
upon
tert-butanol
addition.
Similarly,
sigmatropic
lithioalkynyl
yield
methyl-(2Z,4Z)-dienoates
4
methanol
addition
or
unsaturated
lactones
6
aldehyde
ketone
ynolate
intermediate.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(10)
Published: Jan. 14, 2023
[2,3]-Sigmatropic
rearrangement
reaction
involving
sulfonium
ylide
(Doyle-Kirmse
reaction)
generated
from
metal
carbenes
represents
one
of
the
powerful
methods
for
construction
C(sp3
)-S
and
C-C
bonds.
Although
significant
advances
have
been
achieved,
asymmetric
versions
via
generation
ylides
rarely
reported
to
date,
they
so
far
limited
diazo
compounds
as
carbene
precursors.
Here,
we
describe
a
copper-catalyzed
enantioselective
Doyle-Kirmse
azide-ynamide
cyclization,
leading
practical
divergent
assembly
an
array
chiral
[1,4]thiazino[3,2-b]indoles
bearing
quaternary
carbon
stereocenter
in
generally
moderate
excellent
yields
enantioselectivities.
Importantly,
this
protocol
unique
catalytic
non-diazo
approach
unprecedented
[2,3]-sigmatropic
α-imino
carbenes.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(12), P. 9244 - 9253
Published: June 3, 2024
Catalytic
asymmetric
dearomatization
(CADA)
is
a
powerful
tool
for
the
rapid
construction
of
complex
chiral
three-dimensional
cyclic
molecules
featuring
quaternary
carbon
centers
from
readily
available
arenes.
However,
ubiquitous
nonfunctionalized
1-naphthols
to
afford
remains
challenging
and
undeveloped.
This
study
reports
dearomative
[4
+
1]
spiroannulation
via
copper
catalysis.
reaction
features
highly
chemo-,
regio-,
stereoselective
nucleophilic
addition
intramolecular
annulation
cascade
reactive
π-extended
copper-allenylidene,
thus
enabling
practical
synthesis
range
valuable
spirocyclic
enones
bearing
stereocenter
with
high
efficiency.
Furthermore,
this
protocol
applicable
phenols.
Control
experiments
supported
substitution-annulation
mechanism
by
excluding
process
involving
1,3-sigmatropic
shift.
Preliminary
biological
activity
studies
indicated
that
synthesized
hold
significant
promise
as
anticancer
agents
inducing
tumor
cell
apoptosis.
Nature Communications,
Journal Year:
2023,
Volume and Issue:
14(1)
Published: June 30, 2023
Abstract
Prenylated
and
reverse-prenylated
indolines
are
privileged
scaffolds
in
numerous
naturally
occurring
indole
alkaloids
with
a
broad
spectrum
of
important
biological
properties.
Development
straightforward
stereoselective
methods
to
enable
the
synthesis
structurally
diverse
prenylated
indoline
derivatives
is
highly
desirable
challenging.
In
this
context,
most
direct
approaches
achieve
goal
generally
rely
on
transition-metal-catalyzed
dearomative
allylic
alkylation
electron-rich
indoles.
However,
electron-deficient
indoles
much
less
explored,
probably
due
their
diminished
nucleophilicity.
Herein,
photoredox-catalyzed
tandem
Giese
radical
addition/Ireland–Claisen
rearrangement
disclosed.
Diastereoselective
prenylation
reverse-prenylation
proceed
smoothly
under
mild
conditions.
An
array
tertiary
α-silylamines
as
precursors
readily
incorporated
2,3-disubstituted
high
functional
compatibility
excellent
diastereoselectivity
(>20:1
d.r.).
The
corresponding
transformations
secondary
provide
biologically
lactam-fused
one-pot
synthesis.
Subsequently,
plausible
photoredox
pathway
proposed
based
control
experiments.
preliminary
bioactivity
study
reveals
potential
anticancer
property
these
appealing
indolines.
Advanced Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 19, 2025
Abstract
Here,
an
organocatalytic
asymmetric
[1,3]‐sigmatropic
rearrangement
process
for
aryl
ether
insertion
through
C─O
bond
cleavage
and
downstream
transformation
is
reported,
enabling
the
practical
atom‐economic
synthesis
of
diverse
valuable
chiral
benzofuran
derivatives
bearing
a
quaternary
carbon
stereocenter.
The
reaction
shows
wide
substrate
scope,
yielding
moderate
to
good
products
with
excellent
enantioselectivity
diastereoselectivity
(up
>99%
ee
>99:1
d.r.).
Initial
biological
activity
tests
suggest
that
resulting
enantioenriched
hold
potential
as
anticancer
agents.
Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(39), P. 7105 - 7109
Published: Sept. 21, 2023
Highly
enantioselective
propargyl
Claisen
rearrangement
of
O-propargyl
β-ketoesters
was
achieved
under
2.5
mol
%
the
chiral
cobalt
complex
as
catalyst
mild
reaction
conditions.
With
Co(OTf)2
Lewis
acid
and
C1-symmetric
imidazoline-pyrroloimidazolone
pyridine
ligand,
diverse
allenyl-substituted
all-carbon
quaternary
were
obtained
in
good
yields
(up
to
97%
yield)
high
enantioselectivities
98%
ee).
Chemical Science,
Journal Year:
2023,
Volume and Issue:
14(9), P. 2441 - 2446
Published: Jan. 1, 2023
The
first
catalytic
enantioselective
aromatic
Claisen
rearrangement
of
allyl
2-naphthyl
ethers
using
5-10
mol%
π-copper(ii)
complexes
is
reported.
A
Cu(OTf)2
complex
with
an
l-α-homoalanine
amide
ligand
gave
(S)-products
in
up
to
92%
ee.
Conversely,
a
Cu(OSO2C4F9)2
l-tert-leucine
(R)-products
76%
Density-functional-theory
(DFT)
calculations
suggest
that
these
rearrangements
proceed
stepwise
via
tight-ion-pair
intermediates,
and
(S)-
are
enantioselectively
obtained
the
staggered
transition
states
for
cleavage
C-O
bond,
which
rate-determining
step.
Chemical Communications,
Journal Year:
2024,
Volume and Issue:
60(58), P. 7507 - 7510
Published: Jan. 1, 2024
An
asymmetric
dearomatization
reaction
of
benzyl
1-naphthyl
ethers
accelerated
by
a
chiral
N
,
′-dioxide/Co(
ii
)
complex
is
disclosed.
Experiment
results
indicated
that
the
proceeds
via
tight
ion-pair
intermediate.
