Tetrahedron Chem,
Journal Year:
2023,
Volume and Issue:
8, P. 100049 - 100049
Published: Sept. 22, 2023
Transition-metal-catalyzed
allenes-involved
C–H
functionalizations
demonstrate
unique
selectivity
and
undergo
exceptional
pathways
due
to
the
existence
of
elusive
orthogonal
cumulative
C
bonds.
As
a
result,
it
allows
for
diverse
array
activation
reactions,
such
as
allylation,
alkenylation,
allenylation,
dienylation,
propargylation,
annulation.
In
this
review,
we
comprehensively
summarize
noteworthy
aspects
transition-metal-catalyzed
involving
variously
substituted
allenes.
The Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
88(8), P. 4965 - 4974
Published: Nov. 30, 2022
In
this
Perspective,
the
use
of
methanol
and
ethanol
as
C1
C2
feedstocks
in
metal-catalyzed
C-C
couplings
to
π-unsaturated
pronucleophiles
via
hydrogen
auto-transfer
is
surveyed.
these
processes,
alcohol
oxidation
form
an
aldehyde
electrophile
balanced
by
reduction
hydrocarbon
a
transient
organometallic
nucleophile.
Mechanistically
related
reductive
paraformaldehyde
mediated
reductants
or
formic
acid
also
are
described.
These
processes
encompass
first
catalytic
enantioselective
and,
more
broadly,
illustrate
how
native
reducing
ability
alcohols
enable
departure
from
premetalated
reagents
carbonyl
addition.
ChemCatChem,
Journal Year:
2022,
Volume and Issue:
14(16)
Published: April 22, 2022
Abstract
Alkynes
are
one
of
the
most
abundant
feedstocks
for
chemical
transformations.
By
merging
palladium
and
Brønsted
acid
catalysts,
they
converted
into
reactive
allylmetal
species,
which
become
suitable
Tsuji‐Trost
functionalizations
with
complete
atom‐economy.
This
approach,
overcomes
limitations
traditional
methods
that
suffer
from
formation
over‐stoichiometric
amounts
by‐products,
has
been
disclosed
developing
new
C−C
C−Het
bond
forming
methodologies.
Within
this
review,
we
aim
to
survey
latest
advancements
in
area
including
applications
polymer
chemistry,
deuterium‐labeling
stereoselective
catalysis.
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(22), P. 4830 - 4834
Published: May 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.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(23)
Published: March 31, 2023
Abstract
The
first
metal‐catalyzed
oxidative
alkynylations
of
primary
alcohols
or
aldehydes
to
form
α,β‐acetylenic
ketones
(ynones)
are
described.
Deuterium
labelling
studies
corroborate
a
novel
reaction
mechanism
in
which
alkyne
hydroruthenation
forms
transient
vinylruthenium
complex
that
deprotonates
the
terminal
active
alkynylruthenium
nucleophile.
Angewandte Chemie,
Journal Year:
2023,
Volume and Issue:
135(19)
Published: March 3, 2023
Abstract
Catalytic
enantioselective
coupling
of
1,1‐disubstituted
allenes
and
aldehydes
through
regiodivergent
oxidative
cyclization
followed
by
stereoselective
protonation
or
reductive
elimination
promoted
chiral
phosphine‐Co
complexes
is
presented.
Such
processes
represent
unprecedented
unique
reaction
pathways
for
Co
catalysis
that
enable
catalytic
generation
metallacycles
with
divergent
regioselectivity
accurately
controlled
ligands,
affording
a
wide
range
allylic
alcohols
homoallylic
are
otherwise
difficult
to
access
without
the
need
pre‐formation
stoichiometric
amounts
alkenyl‐
allyl‐metal
reagents
in
up
92
%
yield,
>98
:
2
regioselectivity,
dr
>99.5
0.5
er.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(15), P. 8576 - 8582
Published: April 5, 2023
The
first
use
of
1,4-pentadiene
and
1,5-hexadiene
as
allylmetal
pronucleophiles
in
regio-,
anti-diastereo-,
enantioselective
carbonyl
addition
from
alcohol
proelectrophiles
is
described.
As
corroborated
by
deuterium
labeling
experiments,
primary
dehydrogenation
delivers
a
ruthenium
hydride
that
affects
alkene
isomerization
to
furnish
conjugated
diene,
followed
transfer
hydrogenative
addition.
Hydrometalation
appears
be
assisted
the
formation
fluxional
olefin-chelated
homoallylic
alkylruthenium
complex
II,
which
exists
equilibrium
with
its
pentacoordinate
η1
form
enable
β-hydride
elimination.
This
effect
confers
remarkable
chemoselectivity:
while
are
competent
pronucleophiles,
higher
1,n-dienes
not,
olefinic
functional
groups
products
remain
intact
under
conditions
1,4-
1,5-dienes
isomerize.
A
survey
halide
counterions
reveals
iodide-bound
ruthenium-JOSIPHOS
catalysts
uniquely
effective
these
processes.
method
was
used
prepare
previously
reported
C1–C7
substructure
(−)-pironetin
4
vs
12
steps.
ChemistrySelect,
Journal Year:
2024,
Volume and Issue:
9(5)
Published: Jan. 30, 2024
Abstract
A
sustainable
upgrading
of
renewable
bulk
materials,
obtained
by
decomposition
biomass
lignocellulose,
could
facilitate
their
use
in
the
industrial
production
chemicals.
Homogeneous
ruthenium
catalysis
plays
a
fundamental
role
this
area.
The
review
deals
with
upgradation
lignocellulosic
molecules
through
formation
new
C−C
and
C−N
bonds.
Selected
examples
catalytic
bond
forming
reactions
reported
until
mid
2023,
include:
(a)
dehydrogenative
based
couplings
alcohols,
(b)
reductive
amination
carbonyl
compounds,
(c)
direct
C−H
functionalization
(hetero)aromatic
compounds.
These
approaches
fulfill
requirements
sustainability:
application
occurs
without
any
previous
substrate
activation,
thus
reducing
waste.
New
chemicals
containing
intrinsic
molecular
structure
lignocellulose
substrates,
showed
broad
range
applications:
green
fuels,
hydrogen
carriers,
monomers
polymers,
intermediates
fine
pharmaceuticals.
results
discussed
inspire
reader
to
improve
valorization
process,
terms
bio‐substrate
scope
as
well
product
complexity,
more
strategic
applications
methods.
