Angewandte Chemie,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 12, 2024
Abstract
Enantioselective
synthesis
of
(spiro)cyclobutane
derivatives
poses
significant
challenges
yet
holds
promising
applications
for
both
synthetic
and
medicinal
chemistry.
We
report
here
a
nickel‐catalyzed
asymmetric
syn
‐hydrometalative
4‐
exo
‐
trig
cyclization
1,4‐alkynones
to
synthesize
alkenyl
cyclobutanols
with
tetrasubstituted
stereocenter.
This
strategy
features
broad
substrate
scope,
delivering
variety
trifluoromethyl‐containing
rigid
(spiro)carbocycle
skeletons
in
good
yields
high
enantioselectivities
(up
84
%
yield
98.5
:
1.5
er).
The
utility
is
demonstrated
through
stereospecific
transformations
into
fused
spiro
molecules.
Experimental
computational
mechanistic
studies
indicate
that
the
reaction
initiated
by
an
active
Ni−H
species,
carbonyl‐directed
hydrometalation
as
key
regioselective
control.
catalytic
method
provides
general
solution
hydrofunctionalization
alkynes
represents
efficient
pattern
assembling
highly
strained
enantioenriched
bioisosteres.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(6), С. 3588 - 3598
Опубликована: Фев. 3, 2023
Catalytic
enantioselective
functionalization
of
cyclobutenes
constitutes
a
general
and
modular
strategy
for
construction
enantioenriched
complex
cyclobutanes
bearing
multiple
stereogenic
centers,
as
chiral
four-membered
rings
are
common
motifs
in
biologically
active
molecules
versatile
intermediates
organic
synthesis.
However,
synthesis
through
such
remained
significantly
limited.
Herein,
we
report
series
unprecedented
cobalt-catalyzed
carbon-carbon
bond
forming
reactions
that
initiated
carbometalation.
The
protocols
feature
diastereo-
introduction
allyl,
alkynyl,
functionalized
alkyl
groups.
Mechanistic
studies
indicated
an
unusual
1,3-cobalt
migration
subsequent
β-carbon
elimination
cascade
process
occurred
the
allyl
addition.
These
new
discoveries
established
elementary
cobalt
catalysis
extension
diversity
nucleophiles
transformations
cyclobutenes.
Chemical Science,
Год журнала:
2024,
Номер
15(13), С. 4797 - 4803
Опубликована: Янв. 1, 2024
A
highly
enantioselective
[4
+
2]
cycloaddition
of
a
number
simple
olefins
with
cyclic
hetero-diene
dioxopyrrolidines
is
realized
by
chiral
iron(
iii
)/
N
,
′-dioxide
complex
catalyst.
Accounts of Chemical Research,
Год журнала:
2023,
Номер
56(16), С. 2253 - 2264
Опубликована: Авг. 4, 2023
ConspectusCycloaddition
reactions
are
an
effective
method
to
quickly
build
molecular
complexity.
As
predicted
by
the
Woodward–Hoffmann
rules,
concerted
cycloadditions
with
alkenes
allow
for
constructions
of
all
possible
stereoisomers
product
use
either
Z
or
E
geometry.
While
this
feature
is
widely
used
in,
example,
[4
+
2]
cycloadditions,
translation
[2
challenging
because
often
stepwise
and
therefore
stereoconvergent
nature
these
processes.
Over
past
decade,
our
lab
has
explored
Lewis
acid-promoted
electron-deficient
allenes
ketenes
alkenes.
The
concerted,
asynchronous
synthesis
various
cyclobutanes
control
stereochemistry.Our
developed
first
examples
ketene–alkene
cycloadditions.
Compared
traditional
thermal
conditions,
conditions
have
several
advantages,
such
as
increased
reactivity,
yield,
improved
diastereoselectivity,
and,
certain
cases,
inverse
diastereoselectivity.
Detailed
mechanistic
studies
revealed
that
diastereoselectivity
was
controlled
size
substituent
barrier
a
deconjugation
event.
However,
required
stoichiometric
amounts
EtAlCl2
inhibition,
which
led
us
investigate
catalytic
enantioselective
allenoates
Through
chiral
oxazaborolidines,
broad
range
can
be
prepared
enantioselectivity.
Mechanistic
experiments,
including
2D-labled
Hammett
analysis,
illuminate
likely
transition
state
models
Additional
development
acid-catalyzed
intramolecular
stereoselective
allenic
ketones/esters
alkenes.The
methods
we
been
instrumental
in
families
natural
products.
Specifically,
one
key
lactone
motif
(±)-gracilioether
F
constructed
cycloaddition
subsequent
regioselective
Baeyer–Villiger
oxidation
sequence.
Enantioselective
allenoate–alkene
allowed
(−)-hebelophyllene
E.
Another
attempt
applying
(+)-[5]-ladderanoic
acid
failed
deliver
desired
cyclobutane
unexpected
rearrangement.
later
assembled
carboboration/Zweifel
olefination
process.
Finally,
ketones
applied
syntheses
(−)-[3]-ladderanol,
(+)-hippolide
J,
(−)-cajanusine.
European Journal of Organic Chemistry,
Год журнала:
2023,
Номер
27(4)
Опубликована: Ноя. 21, 2023
Abstract
Although
the
asymmetric
catalysis
has
made
a
spurt
of
progress,
use
chiral
auxiliaries
remains
crucial
in
synthesis
due
to
both
reliability
and
versatility
methods,
predictability
stereochemistry
reactions.
Up
date,
Evans’
non‐racemic
oxazolidinone‐based
synthetic
methodology
is
still
widely
used
synthesis.
More
importantly,
Evans
turned
out
be
fruitful
source
inspiration
for
development
related
methodologies.
However,
although
reviews
on
application
organic
medicinal
chemistry
continually
appear
literature,
comprehensive
review
dedicating
extensions
elusive.
In
this
review,
we
summarize
methodology,
which
cover:
(1)
modification
oxazolidinone
auxiliaries;
(2)
extension
aldol
reaction
from
syn
‐aldol
other
diastereomeric
adducts;
(3)
types;
(4)
imide‐type
substrates
N
‐alkenyl,
‐allenenyl
‐alkynyl
oxazolidinones;
(5)
achiral
catalysis;
(6)
catalytic
transformation
products;
(7)
straightforward
transformations
products
classes
compounds
than
carboxylic
acids,
esters,
alcohols,
Weinreb
amides.
Chemistry - A European Journal,
Год журнала:
2024,
Номер
30(39)
Опубликована: Май 7, 2024
Axially
chiral
cycloalkylidenes
are
interesting
but
less
developed
axially
molecules.
Here,
a
bispidine-based
amine
catalytic
system
was
to
promote
efficiently
the
asymmetric
Knoevenagel
condensation
of
N-protected
oxindoles
and
benzofuranones
with
4-substituted
cyclohexanones.
A
variety
alkylidenecycloalkanes
stable
axial
chirality
were
obtained
in
good
yields
fairly
er
(enantiomeric
ratio).
Based
on
absolute
configuration
determination
product
DFT
calculations,
possible
mechanism
stereoselective
induction
proposed.
Advanced Synthesis & Catalysis,
Год журнала:
2024,
Номер
366(15), С. 3257 - 3261
Опубликована: Июнь 3, 2024
Abstract
Enantioselective
reduction
of
cyclobutenones
to
optically
active
cyclobutanones
has
been
achieved
by
using
whole‐cell
overexpressing
Seqenzym
ene‐reductases
(EREDs).
By
these
enzymes,
trans
‐cyclobutanones
were
isolated
in
good
yields
and
with
enantiomeric
excesses
up
99%.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
145(1), С. 610 - 625
Опубликована: Дек. 20, 2022
Enantioselective
[2
+
2]
cyclization
between
an
imine
and
a
carbon–carbon
double
bond
is
versatile
strategy
to
build
chiral
azetidines.
However,
α-branched
allenoates
have
never
been
successfully
applied
in
reactions
with
imines,
as
they
always
undergo
Kwon's
[4
annulation
previous
catalytic
methods.
Herein,
simple
situ
generated
magnesium
catalyst
was
employed
achieve
the
enantioselective
reaction
of
DPP-imines
for
first
time.
Insightful
experiments
including
KIE
experiments,
controlled
Hammett
plot
analysis,
31P
NMR
studies
initial
intermediates
indicate
that
current
most
likely
involves
asynchronous
concerted
transition
state.
Further
mechanistic
investigations
by
combining
kinetic
studies,
ESI
coordination
complexes,
on
rates
under
different
loading
amounts
provided
details
this
allenoates.
This
new
approach
synthesis
various
aza-heterocycles,
key
intermediate
lipid-lowering
agent
Ezetimibe.