Organometallics,
Год журнала:
2020,
Номер
39(17), С. 3232 - 3239
Опубликована: Авг. 31, 2020
The
titanocene
imido
complex
2
with
a
m-terphenyl
moiety
is
synthesized
by
reacting
Cp2Ti(η2-Me3SiC2SiMe3)
(1)
azide.
Subsequent
reactivity
studies
tetrahydrofuran,
pyridine,
and
nitriles
verify
that
these
substrates
act
as
two-electron
donors,
thus
binding
end-on
to
the
titanium
center
give
donor-stabilized
imides
3a,b
4a–c.
Given
potential
of
an
electron
acceptor,
was
reacted
phosphine
oxides
(OPEt3/OPPh3)
according
Gutmann–Beckett
method
get
information
about
Lewis
acidity
yield
5a,b.
Complex
5a
one
rare
examples
structurally
characterized
complexes
η1-bound
cyclopentadienyl
ligand.
Further
insights
into
were
obtained
from
nitrile
adducts
4a–c
through
IR
spectroscopy
NMR
(δ(19F)
1JC,F
employing
4-fluorobenzontrile).
In
reactions
terminal
alkynes,
respective
amido
acetylides
6a,b
obtained,
whereas
internal
alkynes
demonstrate
not
very
prone
undergoing
[2
+
2]
cycloaddition
reactions.
Chemical Society Reviews,
Год журнала:
2020,
Номер
49(19), С. 6947 - 6994
Опубликована: Янв. 1, 2020
Atlas
as
a
Titan(ium)
is
holding
the
earth-abundant
chemistry
world.
Titanium
second
most
abundant
transition
metal,
key
player
in
important
industrial
processes
(e.g.
polyethylene)
and
shows
much
promise
for
diverse
applications
future.
Journal of the American Chemical Society,
Год журнала:
2019,
Номер
141(10), С. 4194 - 4198
Опубликована: Фев. 7, 2019
The
combination
of
VCl3(THF)3
and
N,N-bis(trimethylsilyl)aniline
(1a)
is
an
efficient
catalyst
for
the
[2+2+1]
coupling
reaction
alkynes
azobenzenes,
giving
multisubstituted
pyrroles.
A
plausible
mechanism
involves
generation
a
mono(imido)vanadium(III)
species
as
initiation
step,
where
1a
served
imido
source
with
concomitant
release
2
equiv
ClSiMe3,
followed
by
azobenzene
to
form
catalytically
active
bis(imido)vanadium(V)
via
N═N
bond
cleavage.
Journal of the American Chemical Society,
Год журнала:
2020,
Номер
142(9), С. 4390 - 4399
Опубликована: Фев. 11, 2020
Pyrazoles
are
an
important
class
of
heterocycles
found
in
a
wide
range
bioactive
compounds
and
pharmaceuticals.
Pyrazole
synthesis
often
requires
hydrazine
or
related
reagents
where
intact
N–N
bond
is
conservatively
installed
into
pyrazole
precursor
fragment.
Herein,
we
report
the
multicomponent
oxidative
coupling
alkynes,
nitriles,
Ti
imido
complexes
for
multisubstituted
pyrazoles.
This
modular
method
avoids
potentially
hazardous
like
hydrazine,
instead
forming
final
step
via
oxidation-induced
on
Ti.
The
mechanism
this
transformation
has
been
studied
in-depth
through
stoichiometric
reactions
key
diazatitanacyclohexadiene
intermediate,
which
can
be
accessed
imidos
with
nitriles
ring
opening
2-imino-2H-azirines,
direct
metalation
4-azadiene-1-amine
derivatives.
critical
reaction
2-electron
rare
example
formal
metal
center,
likely
occurs
electrocyclic
analogous
to
Nazarov
cyclization.
Conveniently,
these
2-electron-oxidized
intermediates
disproportionation
1-electron-oxidized
species,
allows
utilization
weak
oxidants
such
as
TEMPO
Green Synthesis and Catalysis,
Год журнала:
2022,
Номер
4(1), С. 20 - 34
Опубликована: Июнь 23, 2022
The
pyrrole
moiety
is
an
important
structural
motif
in
functional
materials,
natural
products,
and
pharmaceuticals.
More
more
synthetic
strategies
toward
pyrroles
have
emerged,
where
various
efficient
building
blocks
are
developed
these
synthons
enable
the
syntheses
of
with
different
numbers
components.
However,
no
review
specifically
summarizes
according
to
type
number
employed
blocks.
To
aid
researchers
design
appropriate
substrates
for
synthesis,
herein
we
summarized
advances
classified
reactions
into
four
categories
components,
which
may
shed
light
on
developing
methods
substituted
pyrroles.
Angewandte Chemie International Edition,
Год журнала:
2020,
Номер
59(39), С. 17239 - 17244
Опубликована: Июнь 10, 2020
The
first
Pd-catalyzed
enantioselective
azidation
of
unactivated
alkenes
has
been
established
by
using
readily
accessible
1-azido-1,2-benziodoxol-3(1H)-one
(ABX)
as
an
azidating
reagent,
which
affords
a
wide
variety
structurally
diverse
3-N3
-substituted
piperidines
in
good
yields
with
excellent
enantioselectivity.
reaction
features
functional-group
compatibility
and
mild
conditions.
Notably,
both
electrophilic
reagent
the
sterically
bulky
chiral
pyridinyl-oxazoline
(Pyox)
ligand
are
crucial
to
successful
reaction.
Journal of the American Chemical Society,
Год журнала:
2020,
Номер
142(49), С. 20566 - 20571
Опубликована: Ноя. 28, 2020
A
zirconium-catalyzed
hydroaminoalkylation
of
alkynes
to
access
α,β,γ-substituted
allylic
amines
in
an
atom-economic
fashion
is
reported.
The
reaction
compatible
with
N-(trimethylsilyl)benzylamine
and
a
variety
N-benzylaniline
substrates,
the
latter
giving
amine
as
sole
organic
product.
Various
internal
electron-withdrawing
electron-donating
substituents
were
tolerated.
Model
intermediates
synthesized
structurally
characterized.
Stoichiometric
studies
on
key
revealed
that
open
coordination
sphere
at
zirconium,
imparted
by
tethered
bis(ureate)
ligand,
crucial
for
neutral
donors.
These
complexes
may
serve
models
inner-sphere
protonolysis
reactions
required
catalytic
turnover.
Chemical Science,
Год журнала:
2021,
Номер
12(19), С. 6543 - 6550
Опубликована: Янв. 1, 2021
Totally
different
functionalization
and
construction
as
two
fundamental
synthetic
protocols
have
long
been
applied
to
furnish
azaarene
variants.
Here,
a
novel
radical-based
functionalization-oriented
strategy
by
exploiting
the
electronic
properties
of
azaarenes
high
reactivity
radicals
is
developed.
Under
photoredox
catalysis
platform,
robust
ability
such
an
artful
combination
with
disclosed
in
synthesis
valuable
3-azaarene-substituted
densely
functionalized
pyrroles.
In
addition
use
readily
accessible
feedstocks,
efficiency
good
functional
group
tolerance,
substrate
scope
broad
(81
examples)
resulting
from
capability
flexibly
replace
types
other
substituents.
Control
experiments
density
theory
(DFT)
calculations
elucidate
plausible
mechanism
involving
reaction
pathways
important
role
NaH2PO4
additive
reaction.
