Angewandte Chemie International Edition,
Год журнала:
2018,
Номер
57(15), С. 4048 - 4052
Опубликована: Март 7, 2018
Abstract
The
asymmetric
synthesis
of
alkynyl
and
monofluoroalkenyl
isoindolinones
from
N‐methoxy
benzamides
α,α‐difluoromethylene
alkynes
is
enabled
by
C−H
activation
with
a
chiral
CpRh
III
catalyst.
Remarkably,
product
formation
solvent‐dependent;
are
afforded
in
MeOH
(up
to
86
%
yield,
99.6
ee
)
whereas
generated
i
PrCN
98:2
Z
/
E
,
93
).
Mechanistic
studies
revealed
allene
‐configured
alkenyl
rhodium
species
as
reaction
intermediates.
latter
transformed
into
the
corresponding
monofluoroalkene
upon
protonation
system
an
alkyne
unusual
anti
β‐F
elimination
system.
Notably,
kinetic
resolution
processes
occur
this
reaction.
Despite
moderate
enantiocontrol
for
allene,
‐monofluoroalkenyl
were
obtained
good
enantiopurities
one
or
two
sequential
processes.
Chemical Society Reviews,
Год журнала:
2016,
Номер
45(10), С. 2900 - 2936
Опубликована: Янв. 1, 2016
C–H
Activation
reactions
that
proceed
under
mild
conditions
are
more
attractive
for
applications
in
complex
molecule
synthesis.
Mild
transformations
reported
since
2011
reviewed
and
the
different
concepts
strategies
have
enabled
their
mildness
discussed.
Chemical Reviews,
Год журнала:
2017,
Номер
117(23), С. 13810 - 13889
Опубликована: Ноя. 1, 2017
Transition-metal-catalyzed
cross-coupling
reactions
have
been
well-established
as
indispensable
tools
in
modern
organic
synthesis.
One
of
the
major
research
goals
area
is
expanding
scope
coupling
partners.
In
past
decade,
diazo
compounds
(or
their
precursors
N-tosylhydrazones)
emerged
nucleophilic
partners
C-C
single
bond
or
C═C
double
formations
transition-metal-catalyzed
reactions.
This
type
reaction
involves
following
general
steps.
First,
organometallic
species
generated
by
various
processes,
including
oxidative
addition,
transmetalation,
cyclization,
cleavage,
and
C-H
activation.
Subsequently,
reacts
with
substrate
to
generate
metal
carbene
intermediate,
which
undergoes
rapid
migratory
insertion
form
a
bond.
The
new
from
may
undergo
transformations.
carbene-based
has
proven
be
general:
transition
metals
Pd,
Cu,
Rh,
Ni,
Co,
Ir
are
effective
catalysts;
also
extended
substrates
other
than
compounds;
cascade
processes
devised
based
on
insertion.
review
will
summarize
achievements
made
this
field
since
2001.
Chemical Reviews,
Год журнала:
2017,
Номер
117(13), С. 8908 - 8976
Опубликована: Фев. 17, 2017
The
development
of
new
methods
for
the
direct
functionalization
unactivated
C-H
bonds
is
ushering
in
a
paradigm
shift
field
retrosynthetic
analysis.
In
particular,
catalytic
enantioselective
represents
highly
atom-
and
step-economic
approach
toward
generation
structural
complexity.
However,
as
result
their
ubiquity
low
reactivity,
controlling
both
chemo-
stereoselectivity
such
processes
constitutes
significant
challenge.
Herein
we
comprehensively
review
all
asymmetric
transition-metal-catalyzed
methodologies
that
are
believed
to
proceed
via
an
inner-sphere-type
mechanism,
with
emphasis
on
nature
stereochemistry
generation.
Our
analysis
serves
document
considerable
rapid
progress
within
field,
while
also
highlighting
limitations
current
methods.
Accounts of Chemical Research,
Год журнала:
2015,
Номер
48(5), С. 1308 - 1318
Опубликована: Апрель 17, 2015
ConspectusTransition-metal
catalyzed
C–H
functionalizations
became
a
complementary
and
efficient
bond-forming
strategy
over
the
past
decade.
In
this
respect,
Cp*Rh(III)
complexes
have
emerged
as
powerful
catalysts
for
broad
spectrum
of
reactions
giving
access
to
synthetically
versatile
building
blocks.
Despite
their
high
potential,
corresponding
catalytic
enantioselective
transformations
largely
lag
behind.
The
targeted
require
all
remaining
three
coordination
sites
central
rhodium
atom
catalyst.
consequence,
chiral
information
on
competent
catalyst
can
only
by
stored
in
cyclopentadienyl
unit.
lack
suitable
enabling
(Cpx)
ligands
is
key
hurdle
preventing
development
such
asymmetric
versions.
an
set
Cpx
useable
with
variety
different
transition-metals
unlock
substantial
application
potential.
This
Account
provides
description
our
developments
two
classes
C2-symmetric
derivatives.
We
introduced
side-
back-wall
concept
enforce
chirality
transfer
onto
metal
atom.
first
generation
consists
fused
cyclohexane
unit
having
pseudo
axial
methyl
groups
selectors
rigidifying
acetal
moiety.
second
ligand
derives
from
atrop-chiral
biaryl-backbone
which
possesses
adjustable
substituents
at
its
3,3′-positions.
Both
families
be
modulated
respective
steric
bulk
adjust
specific
needs
application.
cyclopentadienes
metalated
under
standard
conditions.
rhodium(I)
ethylene
are
relatively
air
moisture
represent
storable
stable
precatalysts
Rh(III)-catalyzed
functionalizations.
These
then
conveniently
oxidized
situ
dibenzoyl
peroxide
give
reactive
CpxRh(III)(OBz)2
species.
For
instance,
used
directed
activations
aryl
hydroxamates
subsequent
trapping
olefins,
providing
dihydroisoquinolones
very
enantioselectivities.
addition,
we
established
highly
selective
intramolecular
tethered
higher
substituted
alkenes
dihydrobenzofurans
quaternary
stereogenic
centers.
Concerning
intermolecular
reactions,
allene
coupling
partners
allow
hydroarylation
yielding
allylated
compounds.
A
process
cyclometalated
intermediate
diazo
reactants
enables
construction
isoindolinones.
Moreover,
atropchiral
biaryl
motives
using
dehydrogenative
Heck-type
reaction.
flexibly
described
showcasing
applicability
Rh(III)
functionalization
reactions.
derivatives
hold
promise
steering
further
catalysis.
Angewandte Chemie International Edition,
Год журнала:
2016,
Номер
55(36), С. 10578 - 10599
Опубликована: Авг. 1, 2016
Abstract
Achieving
selective
C−H
activation
at
a
single
and
strategic
site
in
the
presence
of
multiple
bonds
can
provide
powerful
generally
useful
retrosynthetic
disconnection.
In
this
context,
directing
group
serves
as
compass
to
guide
transition
metal
by
using
distance
geometry
recognition
parameters
distinguish
between
proximal
distal
bonds.
However,
installation
removal
groups
is
practical
drawback.
To
improve
utility
approach,
one
seek
solutions
three
directions:
1)
Simplifying
group,
2)
common
functional
or
protecting
groups,
3)
attaching
substrates
via
transient
covalent
bond
render
catalytic.
This
Review
describes
rational
development
an
extremely
simple
yet
broadly
applicable
for
Pd
II
,
Rh
III
Ru
catalysts,
namely
N‐methoxy
amide
(CONHOMe)
moiety.
Through
collective
efforts
community,
wide
range
transformations
type
have
been
developed.
Angewandte Chemie International Edition,
Год журнала:
2016,
Номер
55(37), С. 11000 - 11019
Опубликована: Июнь 22, 2016
The
exponential
increase
in
the
number
of
catalytic
transformations
that
involve
a
metal-promoted
activation
hitherto
considered
inert
C-H
bonds
is
promoting
fundamental
change
field
synthetic
chemistry.
Although
most
reactions
involving
activations
consist
simple
functionalizations
or
additions,
recent
years
have
witnessed
an
upsurge
related
can
be
formally
as
cycloaddition
processes.
These
are
particularly
appealing
from
perspective
because
they
allow
conversion
readily
available
substrates
into
highly
valuable
cyclic
products
rapid
and
sustainable
manner.
In
many
cases,
these
annulations
formation
metallacyclic
intermediates
resemble
those
proposed
for
standard
metal-catalyzed
cycloadditions
unsaturated
precursors.
Journal of the American Chemical Society,
Год журнала:
2016,
Номер
138(16), С. 5242 - 5245
Опубликована: Апрель 12, 2016
The
vastly
increasing
application
of
chiral
Cp
ligands
in
asymmetric
catalysis
results
growing
demand
for
novel
ligands.
Herein,
we
report
a
new
class
based
on
1,1′-spirobiindane,
privileged
scaffold
and
catalysts.
corresponding
Rh
complexes
are
shown
to
be
excellent
catalysts
oxidative
coupling
reactions,
providing
axially
biaryls
19–97%
yields
with
up
98:2
er.
Journal of the American Chemical Society,
Год журнала:
2015,
Номер
137(4), С. 1623 - 1631
Опубликована: Янв. 8, 2015
Rh(III)-catalyzed
C–H
activation
assisted
by
an
oxidizing
directing
group
has
evolved
to
a
mild
and
redox-economic
strategy
for
the
construction
of
heterocycles.
Despite
success,
these
coupling
systems
are
currently
limited
cleavage
N–O
or
N–N
bond.
Cleavage
C–N
bond,
which
allows
complementary
carbocycle
synthesis,
is
unprecedented.
In
this
article,
α-ammonium
acetophenones
with
bond
have
been
designed
as
substrates
under
redox-neutral
conditions.
The
α-diazo
esters
afforded
benzocyclopentanones,
unactivated
alkenes
such
styrenes
aliphatic
olefins
gave
ortho-olefinated
acetophenoes.
both
reactions
proceeded
broad
scope,
high
efficiency,
functional
tolerance.
Moreover,
efficient
one-pot
diazo
realized
starting
from
α-bromoacetophenones
triethylamine.
reaction
mechanism
studied
combination
experimental
theoretical
methods.
particular,
three
distinct
mechanistic
pathways
scrutinized
DFT
studies,
revealed
that
occurs
via
C-bound
enolate-assisted
concerted
metalation–deprotonation
rate-limiting.
subsequent
C–C
formation
steps,
lowest
energy
pathway
involves
two
rhodium
carbene
species
key
intermediates.
Angewandte Chemie International Edition,
Год журнала:
2014,
Номер
53(48), С. 13244 - 13247
Опубликована: Окт. 24, 2014
Abstract
Enantioselective
construction
of
axially
chiral
biaryls
by
direct
CH
bond
functionalization
reactions
has
been
realized.
Novel
were
synthesized
the
olefination
biaryl
compounds,
using
a
[Cp*Rh
III
]
catalyst,
in
good
to
excellent
yields
and
enantioselectivities.
The
obtained
found
as
suitable
ligands
for
rhodium‐catalyzed
asymmetric
conjugate
additions.