β-Hydroxy Esters as Malonic Semialdehyde Proelectrophiles in Enantioselective Butadiene-Mediated Crotylation: Total Synthesis of Octalactins A and B
Organic Letters,
Год журнала:
2024,
Номер
26(22), С. 4830 - 4834
Опубликована: Май 28, 2024
Tractable
and
commercially
available
esters
(and
amides)
of
β-hydroxypropionic
acid
serve
as
malonic
semialdehyde
proelectrophiles
in
enantioselective
ruthenium-catalyzed
hydrogen
autotransfer
crotylations
mediated
by
butadiene.
Through
iterative
asymmetric
butadiene-mediated
ethyl
3-hydroxypropanoate,
total
syntheses
the
polyketide
natural
products
octalactin
A
B
were
achieved
fewer
steps
than
previously
possible.
Язык: Английский
Half-Sandwich Ru(II) Complexes Featuring Metal-Centered Chirality: Configurational Stabilization by Ligand Design, Preparation via Kinetic Resolution, and Application in Asymmetric Catalysis
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 12, 2025
While
it
is
well
established
that
half-sandwich
Ru(II)
complexes
possess
metal-centered
chirality,
effective
strategies
to
leverage
their
chirality
toward
asymmetric
synthesis
have
been
challenging
due
the
configurational
lability
of
metal
stereocenters.
The
typically
mediated
by
enantiopure
ligands,
which
occupy
a
relatively
narrow
chemical
space
compared
achiral
counterparts.
We
demonstrate
ligands
can
be
used
access
chiral-at-ruthenium
with
exceptionally
high
stability.
Key
success
introduction
rigid
bidentate
ligand
minimized
dihedral
angle
between
pyridyl
and
phenolic
moieties,
proved
for
preventing
racemization.
Computational
studies
revealed
energetic
factors
contributing
exceptional
stability
enabled
planar
structure
successful
design.
These
optically
active
incorporating
aldehyde
moieties
were
obtained
NHC-catalyzed
kinetic
resolution
excellent
selectivities
(s-factor
up
>200,
ee
99%).
further
they
are
highly
chiral
catalysts
1,6-conjugate
addition
glycine
ester
para-quinone
methide.
Язык: Английский
Dirhodium Complexes Heterochiral-at-the-Metal Centers: An Alternative Type of Paddlewheel Catalyst for Asymmetric Synthesis
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 4, 2025
The
prototype
of
an
entirely
new
class
dirhodium
paddlewheel
complexes
is
disclosed,
which
chiral
at
both
inequivalent
metal
centers
although
it
carries
just
three
different
achiral
μ-bridging
equatorial
ligands.
One
them
a
carboxamidate,
ensures
selective
carbene
formation
the
Rh[O3N]
face
catalyst;
moreover,
-NH
group
engages
ester
carbonyl
emerging
rhodium
intermediate
derived
from
α-stannylated
α-diazoacetate
in
interligand
hydrogen
bonding,
critically
important
for
controlling
stereochemical
course
ensuing
[2
+
1]
cycloaddition.
heterochiral
catalyst
furnished
stannylated
cyclopropane
derivatives
with
excellent
diastereo-
and
enantioselectivity;
quaternary
trifluoromethylated
stereocenter
was
obtained
unprecedented
level
asymmetric
induction.
Язык: Английский
Formal Synthesis of Fostriecin via Asymmetric Alcohol-Mediated Carbonyl Allylation
Organic Letters,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 10, 2025
A
formal
synthesis
of
fostriecin
via
convergent
assembly
two
fragments
prepared
asymmetric
alcohol-mediated
C-C
coupling
is
described.
One
fragment
made
by
the
enantioselective
iridium-catalyzed
allylation
an
allylic
alcohol
mediated
allyl
acetate.
The
other
ruthenium-catalyzed
reductive
syn-(α-alkoxy)allylation
aldehyde
alkoxyallene
(where
2-propanol
hydrogen
source),
representing
first
use
this
method
in
target-oriented
synthesis.
Metathetic
union
enables
interception
a
late-stage
compound
that
previously
required
25
step
(LLS)
only
7
steps
(LLS).
Язык: Английский
Asymmetric Allylic Amination of Alkyl-Substituted Allylic Carbonates with Pyridones Catalyzed by the Krische Iridium Complex
Organic Letters,
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 27, 2024
An
efficient
Ir-catalyzed
asymmetric
allylic
amination
reaction
of
alkyl-substituted
carbonates
is
disclosed.
With
the
Krische
iridium
complex
as
catalyst,
with
pyridones
proceeds
effectively,
affording
pyridone
derivatives
containing
a
stereocenter
α
to
nitrogen
atom
in
excellent
yields
and
enantioselectivity
(up
99%
yield,
95%
ee).
This
catalytic
system
broadens
substrate
scope
compared
that
known
systems.
can
also
be
conducted
on
gram
scale,
further
enhancing
its
potential
for
synthetic
application.
Язык: Английский
Catalytic Enantioselective C–C Coupling of Alcohols for Polyketide Total Synthesis beyond Chiral Auxiliaries and Premetalated Reagents
Chemical Reviews,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 6, 2024
Catalytic
enantioselective
hydrogen
autotransfer
reactions
for
the
direct
conversion
of
lower
alcohols
to
higher
are
catalogued
and
their
application
total
synthesis
polyketide
natural
products
is
described.
These
methods
exploit
a
redox
process
in
which
alcohol
oxidation
balanced
by
reductive
generation
organometallic
nucleophiles
from
unsaturated
hydrocarbon
pronucleophiles.
Unlike
classical
carbonyl
additions,
premetalated
reagents,
chiral
auxiliaries
discrete
alcohol-to-aldehyde
not
required.
Additionally,
chemoselective
dehydrogenation
primary
presence
secondary
enables
C-C
coupling
absence
protecting
groups.
Язык: Английский