Mechanism and stereoselectivity in metal and enzyme catalyzed carbene insertion into X–H and C(sp2)–H bonds
Chemical Society Reviews,
Год журнала:
2024,
Номер
53(22), С. 11004 - 11044
Опубликована: Янв. 1, 2024
This
review
provides
a
mechanistic
overview
of
asymmetric
Fe,
Cu,
Pd,
Rh,
Au
and
heme-based
enzymes
catalyzed
carbene
insertion
reactions
to
construct
C–X
(X
=
O,
N,
S,
etc.
)
C–C
bonds,
focusing
on
the
stereochemical
models.
Язык: Английский
Metal-Associated Enols as Key Intermediates in Controlling Enantioselectivity in Carbene Insertion Reactions
Synlett,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 11, 2025
Abstract
Transition-metal-catalysed
asymmetric
carbene
insertion
reactions
into
various
X–H
bonds
typically
suffer
from
poor
stereoselectivity.
It
has
been
proposed
that
the
presence
of
metal-free
intermediates
leads
to
erosion
selectivity.
In
current
account,
we
discuss
our
recent
efforts
understand
mechanism
and
stereochemical
model
Rh-
Fe-catalysed
indole
phenol.
Our
detailed
DFT
calculations
show
all
transformations
adopt
a
common
involving
an
enol
intermediate,
further
tautomerisation
which
is
key
stereodetermining
step.
To
account
for
enantioinduction,
propose
novel
metal-associated
species
can
be
solving
challenges
in
reactions.
The
geometry
metal–enol
complex
interaction
between
chiral
metal
prochiral
play
important
roles
driving
reaction
toward
particular
stereoisomer.
1
Introduction
2
Rh-Catalysed
Carbene
Insertion
Indole
3
Fe-Catalysed
C–H
Functionalisation
4
O–H
5
Conclusion
Язык: Английский
A combined experimental and computational study reveals a crossover between conventional cross-coupling and carbene insertion pathways in a Pd catalyzed C(sp2)–H insertion
Chemical Science,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 1, 2025
Computational
(DFT
and
DLPNO-CCSD(T))
calculations
along
with
experimental
tools
(deuterium
labelling,
kinetic
studies
using
VTNA,
ESI-HRMS
UV)
are
used
to
probe
the
mechanism
of
a
Pd(ii)-catalyzed
enantioselective
carbene
insertion
into
C(sp2)-H
indole.
Using
deuterium
labelling
studies,
we
demonstrate
intermediacy
metal-hydride
species,
which
contrasts
mechanistic
routes
for
other
transition
metals
(Rh,
Fe,
Au,
Cu,
etc.).
Our
VTNA
study
reveals
order
be
one
in
both
diazo
indole,
microkinetic
modelling
aligns
well
computationally
predicted
mechanism.
The
is
further
supported
by
detection
most
stable
intermediate
catalytic
cycle
ESI-HRMS.
An
investigation
origin
stereoselectivity
DLPNO-CCSD(T)
presents
new
paradigm,
wherein
stereocontrol
arises
during
formation
Pd
itself
as
opposed
proton
transfer
steps
found
all
metal
catalysts.
Язык: Английский
Unveiling the Importance of Catalyst Framework and Non Covalent Interactions in an Asymmetric Fe-Catalyzed O–H Insertion: Insights from Computational Tools
Chemical Communications,
Год журнала:
2024,
Номер
60(75), С. 10322 - 10325
Опубликована: Янв. 1, 2024
Fe-based
catalysts
as
well
enzymes
typically
yield
low
stereoselectivity
for
carbene
insertion
into
X-H
bonds.
Here,
we
have
utilized
DFT
methods
to
understand
the
mechanism
and
unusually
high
enantioselectivity
in
an
Fe-spiroBox
catalyzed
reaction
O-H
bond
of
aliphatic
alcohols.
Our
transition
state
model
shows
a
unique
binding
intermediates
chiral
catalyst
enabled
by
weak
non
covalent
interactions
that
is
absent
other
reactions.
Язык: Английский
Three‐component allylic alkylation reaction of α‐diazo ketones with water and allyl carbonates for construction of homoallylic alcohols
Advanced Synthesis & Catalysis,
Год журнала:
2024,
Номер
366(17), С. 3616 - 3623
Опубликована: Июнь 20, 2024
Abstract
A
three‐component
allylic
alkylation
reaction
of
α‐diazo
ketones,
water
and
allyl
carbonate
under
the
cooperative
catalysis
Rh
2
(OAc)
4
,
Pd
(dba)
3
Brønsted
acid
was
disclosed.
This
method
provides
an
expeditious
access
to
α‐keto
homoallylic
alcohols
in
good
high
yields.
Controlled
experiments
support
that
transformations
proceed
through
cross‐interception
two
active
intermediates
Pd‐allyl
species
enol
derived
from
oxonium
ylides.
Moreover,
synthetic
generated
products
enable
creation
motifs
enriched
with
dense
functional
groups,
underscoring
their
potential
as
valuable
building
blocks.
Язык: Английский
Cesium and Phenoxide Interaction Enabled by Rh Overrides the Innate Solvent-Mediated Chemoselectivity
ACS Catalysis,
Год журнала:
2024,
Номер
14(16), С. 12351 - 12358
Опубликована: Авг. 5, 2024
DLPNO-CCSD(T)
calculations
are
carried
out
to
understand
the
distinctive
chemoselectivity
in
a
Rh(II)-catalyzed
carbene
insertion
into
C(sp2)–H
bond
unprotected
phenols
without
preinstalled
directing
groups.
As
per
conventional
rules
of
solvation
and
separated
ion
pair
polar
aprotic
solvents
like
acetonitrile,
reaction
should
have
resulted
an
O–H
insertion.
However,
our
reveal
transition
state
model
that
helps
overriding
innate
acetonitrile.
It
involves
explicit
participation
added
Cs2CO3
base,
where
interaction
between
phenoxide
oxygen
Cs
cation,
but
not
as
metal-bound
phenoxide,
is
crucial
for
controlling
chemoselectivity.
Our
study
will
be
helpful
developing
further
reactions
with
broad
catalyst,
substrate,
solvent
scope.
Язык: Английский