SSRN Electronic Journal,
Год журнала:
2022,
Номер
unknown
Опубликована: Янв. 1, 2022
Presented
herein
is
an
effective
synthesis
of
1,3-benzooxazine
spirosuccinimide
derivatives
through
Rh(III)-catalyzed
formal
[5
+
1]
annulation
reaction
2-phenoxy-1H
-benzo[
d
]imidazoles
with
maleimides.
Experimental
mechanistic
studies
revealed
that
this
proceeded
sequential
C−H/N−H
bond
cleavage
and
C−C/C−N
formation
along
traceless
fusion
the
NH-directing
group
into
spiroheterocyclic
product.
Compared
previously
reported
methods
for
similar
purpose,
novel
synthetic
protocol
has
advantages
such
as
easily
obtainable
substrates,
environmentally
sustainable
cost-effective
oxidant,
high
atom-economy
ready
scalability.
Organic & Biomolecular Chemistry,
Год журнала:
2024,
Номер
22(12), С. 2324 - 2338
Опубликована: Янв. 1, 2024
This
review
summarizes
the
most
recent
progress
made
in
C–H
bond
activation-initiated
spiroannulation
reactions
and
their
applications
construction
of
structurally
diverse
biologically
valuable
spirocyclic
scaffolds.
Organic Letters,
Год журнала:
2023,
Номер
25(20), С. 3806 - 3811
Опубликована: Май 17, 2023
A
Mn(I)-catalyzed
site-selective
nondirected
C3-maleimidation
of
quinoxaline
is
established.
Herein,
the
electrophilic
C3-metalation
precedes
over
o-directed
strategy
to
access
diversely
substituted
quinoxaline-appended
succinimides.
The
products
undergo
PIFA-promoted
C(sp2)-C(sp3)
spirocyclization
via
π-electrons
drifting
from
aryls
and
Selectfluor-mediated
dehydrogenation
succinimide
at
room
temperature.
The Journal of Organic Chemistry,
Год журнала:
2023,
Номер
88(6), С. 3424 - 3435
Опубликована: Март 3, 2023
A
rhodium(III)-catalyzed
controllable
[4
+
1]
and
2]
annulation
of
N-aryl
pyrazolones
with
maleimides
as
C1
C2
synthon
has
been
explored
for
the
synthesis
spiro[pyrazolo[1,2-a]indazole-pyrrolidines]
fused
pyrazolopyrrolo
cinnolines.
The
product
selectivity
was
achieved
through
time-dependent
annulation.
reaction
involves
sequential
Rh(III)-catalyzed
C-H
alkenylation
pyrazolone,
followed
by
an
intramolecular
spirocyclization
via
aza-Michael-type
addition
to
afford
spiro[pyrazolo[1,2-a]indazole-pyrrolidine].
However,
prolonged
time
converts
in
situ
formed
spiro[pyrazolo[1,2-a]indazole-pyrrolidine]
into
pyrazolopyrrolocinnoline.
This
unique
formation
switch
proceeds
strain-driven
ring
expansion
a
1,2-shift
C-C
bond.
Organic Chemistry Frontiers,
Год журнала:
2022,
Номер
9(19), С. 5185 - 5190
Опубликована: Янв. 1, 2022
An
indazolone-directed
chemoselective
synthesis
of
8
H
-indazolo
[1,2-
a
]cinnolines
has
been
realized
via
cascade
Cp*Ir(
iii
)-
and
Cp*Rh(
)-catalyzed
C–H
activation/cyclization
reaction
1-arylindazolones
with
sulfoxonium
ylides.
The Journal of Organic Chemistry,
Год журнала:
2023,
Номер
88(6), С. 3499 - 3508
Опубликована: Март 9, 2023
Rh(III)-catalyzed
C-H/N-H
annulation
and
C-H
allylation
of
phenylindazolones
have
been
realized
by
employing
5-methylene-1,3-dioxan-2-one
4-vinyl-1,3-dioxolan-2-one
as
scalable
cross-coupling
partners,
delivering
functionalized
indazolone
fused
heterocycles
branched
linear
allyl
indazolones
respectively
in
moderate
to
high
yield.
These
divergent
synthesis
protocols
showcase
mild
conditions,
broad
substrate
scope,
functional-group
compatibility.
In
addition,
scale-up
preliminary
mechanistic
exploratory
were
also
accomplished.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(4), С. 2272 - 2282
Опубликована: Фев. 2, 2024
Synthesis
of
imidazo-fused
polyheterocyclic
molecular
frameworks,
viz.
imidazo[1,2-a]pyrrolo[3,4-e]pyridines,
imidazo[2,1-a]pyrrolo[3,4-c]isoquinolines,
and
benzo[g]imidazo[1,2-a]quinoline-6,11-diones,
has
been
achieved
by
the
ruthenium(II)-catalyzed
[4
+
2]
C–H/N–H
annulation
2-alkenyl/2-arylimidazoles
with
N-substituted
maleimides
1,4-naphthoquinones.
The
developed
protocol
is
operationally
simple,
exhibits
broad
substrate
scope
excellent
functional
group
tolerance,
provides
desired
products
in
moderate
to
good
yields.
mechanistic
studies
suggest
that
reaction
involves
formation
a
C–C
bond
through
Ru-catalyzed
C(sp2)–H
activation
followed
intramolecular
cyclization.
Advanced Synthesis & Catalysis,
Год журнала:
2021,
Номер
364(4), С. 897 - 908
Опубликована: Дек. 18, 2021
Abstract
A
Pd(II)‐catalyzed
atropselective
olefination
of
biaryls
with
maleimides
is
reported
using
chiral
transient
directing
group
(CTDG)
strategy
L‐
tert
‐leucine
used
as
a
auxiliary
to
obtain
biaryl
aldehydes
enantiomeric
excess
ranging
from
70
99%.
The
method
also
applicable
for
other
olefins
such
acrylonitrile,
phenyl
vinyl
sulfone,
and
N
‐
‐butyl
acrylamide,
providing
corresponding
97–99%
ee
.
Non‐linear
effect
studies
suggest
that
responsible
the
atropselectivity
products.
Other
suggested
critical
role
reaction
time
on
yield
s‐factor
desired
magnified
image
European Journal of Organic Chemistry,
Год журнала:
2023,
Номер
26(30)
Опубликована: Июнь 15, 2023
Abstract
An
efficient
Rh(III)‐catalyzed
C−H
alkenylation
of
N
‐protected
isoquinolone
with
maleimides
is
reported.
The
carbonyl
group
acts
as
an
inherent
directing
group.
Various
‐substituents
in
the
maleimide,
including
alkyl,
aryl,
and
even
H
−OH,
were
well
tolerated
under
developed
reaction
condition.
This
protocol
showed
broad
substrate
scope,
good
selectivity,
excellent
yields.
Hammett
plot
also
drawn
to
check
effect
substituents
on
progress.
Synthesis,
Год журнала:
2022,
Номер
54(20), С. 4461 - 4471
Опубликована: Март 30, 2022
Abstract
The
structural
modification
of
phthalazinones
and
indazolones
has
emerged
as
a
pivotal
topic
in
catalytic
C–H
functionalization
events.
Herein
we
report
the
hydrazide-assisted
rhodium(III)-catalyzed
cross-coupling
reactions
N-arylphthalazinones
N-arylindazolones
with
vinylene
carbonate.
This
method
provides
direct
access
to
tetracyclic
hydroxycinnolines.
Complete
site-selectivity
functional
group
compatibility
were
observed.
