Angewandte Chemie,
Journal Year:
2023,
Volume and Issue:
135(32)
Published: June 8, 2023
Abstract
Herein,
we
show
that
the
combination
of
Birch
reduction
readily
available
anisole
derivatives
and
catalytic
asymmetric
inverse‐electron‐demand
Diels–Alder
reaction
2‐pyrones
can
serve
as
a
powerful
platform
for
diverse
synthesis
synthetically
important
cis
‐decalin
scaffolds.
Enabled
by
well‐modified
chiral
bis(oxazoline)
ligand/Cu
II
complex,
wide
range
polysubstituted
scaffolds
with
up
to
six
contiguous
stereocenters
were
generated
efficiently.
The
synthetic
potential
this
method
is
demonstrated
concise
sesquiterpene
(+)‐occidentalol
key
intermediate
seven
triterpenes.
Mechanistic
studies
suggest
1,3‐cyclohexadienes
formed
in
situ
are
intermediates,
efficient
kinetic
resolution
occurs
when
C2‐
and/or
C3‐substituted
1,4‐cyclohexadienes
utilized
substrates.
DFT
calculations
elucidated
proceeds
stepwise
fashion
revealed
origins
stereoselectivities.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(6), P. 4082 - 4092
Published: March 1, 2024
A
series
of
Mo
complexes
bearing
inexpensive
bidentate
bis(NHC)
ligands
have
been
synthesized
and
characterized
by
NMR
IR
spectroscopy
as
well
single
crystal
XRD
analysis.
These
proved
to
be
efficient
for
the
catalytic
hydrogenation
aliphatic
aromatic
esters
(>35
examples)
operating
at
low
catalyst
loadings
(0.5–2
mol
%)
temperatures
(80–120
°C).
Various
functional
groups,
e.g.,
C═C
double
bonds,
nitriles,
alcohols,
tertiary
amines,
halides,
acetals,
heteroaromatic
substrates,
lactones,
diesters,
are
tolerated
optimal
system.
Based
on
spectroscopic
investigations,
control
experiments
DFT
computations
a
non-bifunctional
outer-sphere
mechanism
is
proposed.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
62(32)
Published: June 8, 2023
Herein,
we
show
that
the
combination
of
Birch
reduction
readily
available
anisole
derivatives
and
catalytic
asymmetric
inverse-electron-demand
Diels-Alder
reaction
2-pyrones
can
serve
as
a
powerful
platform
for
diverse
synthesis
synthetically
important
cis-decalin
scaffolds.
Enabled
by
well-modified
chiral
bis(oxazoline)
ligand/CuII
complex,
wide
range
polysubstituted
scaffolds
with
up
to
six
contiguous
stereocenters
were
generated
efficiently.
The
synthetic
potential
this
method
is
demonstrated
concise
sesquiterpene
(+)-occidentalol
key
intermediate
seven
triterpenes.
Mechanistic
studies
suggest
1,3-cyclohexadienes
formed
in
situ
are
intermediates,
efficient
kinetic
resolution
occurs
when
C2-
and/or
C3-substituted
1,4-cyclohexadienes
utilized
substrates.
DFT
calculations
elucidated
proceeds
stepwise
fashion
revealed
origins
stereoselectivities.
Chemistry - An Asian Journal,
Journal Year:
2023,
Volume and Issue:
18(23)
Published: Oct. 10, 2023
Transition
metal-catalyzed
homogeneous
hydrogenation
and
dehydrogenation
reactions
for
attaining
plethora
of
organic
scaffolds
have
evolved
as
a
key
domain
research
in
academia
industry.
These
protocols
are
atom-economic,
greener,
line
with
the
goal
sustainability,
eventually
pave
way
numerous
novel
environmentally
benign
methodologies.
Appealing
progress
has
been
achieved
realm
catalysis
utilizing
noble
metals.
Owing
to
their
high
cost,
less
abundance
along
toxicity
issues
led
scientific
community
search
sustainable
alternatives.
In
this
context,
earth-
abundant
base
metals
gained
substantial
attention
culminating
enormous
recent
years,
predominantly
pincer-type
complexes
nickel,
cobalt,
iron,
manganese.
regard,
group
VI
chromium,
molybdenum
tungsten
overlooked
remain
underdeveloped
despite
earth-abundance
bio-compatibility.
This
review
delineates
comprehensive
overview
arena
homogeneously
catalysed
(de)hydrogenation
using
molybdenum,
till
date.
Various
described;
hydrogenation,
transfer
dehydrogenation,
acceptorless
dehydrogenative
coupling,
hydrogen
auto
transfer,
scope
brief
mechanistic
insights.
Dalton Transactions,
Journal Year:
2024,
Volume and Issue:
53(24), P. 10244 - 10249
Published: Jan. 1, 2024
We
report
here
low-valent
molybdenum
phosphine
complexes
catalyzed
hydrogenation
of
carbon
dioxide,
bicarbonate,
and
inorganic
carbonate
to
formates,
achieving
a
maximum
TON
975
for
the
CO
2
in
THF/H
O
mixture
after
24
h.
Organometallics,
Journal Year:
2023,
Volume and Issue:
42(12), P. 1411 - 1424
Published: June 1, 2023
We
report
the
synthesis
of
17
molybdenum
and
tungsten
complexes
supported
by
ubiquitous
BDI
ligand
framework
(BDI
=
β-diketiminate).
The
focal
entry
point
is
four
tungsten(V)
general
formula
[MO(BDIR)Cl2]
[M
Mo,
R
Dipp
(1);
M
W,
(2);
Mes
(3);
(4)]
synthesized
reaction
between
MoOCl3(THF)2
or
WOCl3(THF)2
LiBDIR.
Reactivity
studies
show
that
BDIDipp
are
excellent
precursors
toward
adduct
formation,
reacting
smoothly
with
dimethylaminopyridine
(DMAP)
triethylphosphine
oxide
(OPEt3).
No
small
phosphines
has
been
observed,
strongly
contrasting
chemistry
previously
reported
rhenium(V)
complexes.
Additionally,
1
2
good
for
salt
metathesis
reactions.
While
can
be
chemically
reduced
to
first
stable
example
a
Mo(IV)
complex
15,
reduction
resulted
in
degradation
via
nitrene
transfer
reaction,
leading
MAD
(4-((2,6-diisopropylphenyl)imino)pent-2-enide)
tungsten(VI)
16
17.
All
have
thoroughly
studied
VT-NMR
(heteronuclear)
NMR
spectroscopy,
as
well
UV-vis
EPR
IR
X-ray
diffraction
analysis.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(38), P. 21027 - 21039
Published: Sept. 13, 2023
The
synthesis
of
phosphino(oxazoline)pyridine-supported
molybdenum(0)
cycloocta-1,5-diene
complexes
is
described.
Exposure
these
to
dihydrogen
in
the
presence
an
arene
resulted
insertion
substrate
into
molybdenum
hydride
bond
and
afforded
corresponding
cyclohexadienyl
hydrides.
For
mono-
disubstituted
arenes,
site
selectivity
for
most
substituted
increases
with
increasing
size
substituent
from
methyl
ethyl,
iso-propyl,
tert-butyl.
In
contrast,
1,3,5-trisubstituted
arenes
underwent
exclusive
selectivity.
Relative
rates
were
determined
by
competition
experiments
established
faster
insertions
electron-rich
arenes.
Introduction
electron-withdrawing
trifluoromethyl
groups
on
decreased
relative
increased
rate
H2
reductive
elimination,
favoring
formation
η6-arene
complex.
Studies
elimination
ligand
enabled
enantioenriched
cyclohexa-1,3-diene.
This
study
provides
new
insights
requirements
catalytic
hydrogenation
a
strategy
selective
reduction.
Nachrichten aus der Chemie,
Journal Year:
2024,
Volume and Issue:
72(2), P. 58 - 65
Published: Jan. 31, 2024
Abstract
Hauptgruppen‐
und
Molekülchemie:
Die
leichteste
Metall‐Metall‐Bindung
im
Bisberyllocen;
ein
doppeltes
Highlight
in
der
Carbenchemie:
C
zweifach
oxidiert
mit
formal
vier
Valenzelektronen
Bor‐Flanken
für
extreme
Lewis‐Azidität;
außergewöhnliche
Liganden
ermöglichen,
ungewöhnlich
reaktive
Spezies
zu
isolieren:
kristallines
Triplett‐Bismutiniden.
Nebengruppen,
Bioanorganik
Koordinationschemie:
Rhodiumnitren,
koordiniertes
Ytterbium
lumineszierendes
Chrom
sowie
quadratisch‐planares
Cu
4
S.
Chemical Communications,
Journal Year:
2023,
Volume and Issue:
59(39), P. 5847 - 5849
Published: Jan. 1, 2023
Non-metal-catalyzed
hydrogenation
of
arenes
represents
a
sustainable
and
environment-friendly
approach
for
the
synthesis
cyclohexane
derivatives.
Herein,
we
report
development
borenium-ion
catalyst
system
which
can
hydrogenate
number
monocyclic
arenes.
Additionally,
this
metal-free
catalytic
allows
selective
partial
or
full
naphthalene
anthracene
by
modification
reaction
conditions.
Our
mechanism
studies
suggest
that
borenium-arene-mediated
H2
splitting
takes
place
before
rate-limiting
step
hydride
transfer
between
resulting
neutral
borane
protonated
arene
is
likely
in
process.
