The Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
88(1), P. 525 - 533
Published: Dec. 16, 2022
Structurally
novel
2-azaspiro[4.5]deca-1,6,9-trien-8-ones
were
synthesized
from
N-(2-propyn-1-yl)
amides
and
1,3,5-trimethoxybenzenes
by
a
tandem
method
consisting
of
Tf2O-promoted
amide
activation
TfOH-promoted
Friedel-Crafts
ipso-cyclization.
The
offered
the
first
example
using
as
substrates
in
both
secondary
synthesis
azaspiro[4.5]deca-6,9-diene-8-ones.
Chemical Reviews,
Journal Year:
2023,
Volume and Issue:
123(16), P. 10079 - 10134
Published: Aug. 1, 2023
This
review
summarizes
the
advancements
in
rhodium-catalyzed
asymmetric
C–H
functionalization
reactions
during
last
two
decades.
Parallel
to
rapidly
developed
palladium
catalysis,
rhodium
catalysis
has
attracted
extensive
attention
because
of
its
unique
reactivity
and
selectivity
reactions.
In
recent
years,
Rh-catalyzed
have
been
significantly
many
respects,
including
catalyst
design,
reaction
development,
mechanistic
investigation,
application
synthesis
complex
functional
molecules.
presents
an
explicit
outline
catalysts
ligands,
mechanism,
scope
coupling
reagents,
applications.
Organic & Biomolecular Chemistry,
Journal Year:
2024,
Volume and Issue:
22(12), P. 2324 - 2338
Published: Jan. 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,
Journal Year:
2022,
Volume and Issue:
24(6), P. 1280 - 1285
Published: Feb. 7, 2022
Synthesis
of
spiro[benzo[d][1,3]oxazine-4,4'-isoquinoline]s
through
a
unique
[4+1+1]
annulation
N-aryl
amidines
with
diazo
homophthalimides
and
O2
is
presented.
This
unprecedented
spirocyclization
reaction
features
readily
obtainable
substrates,
structurally
pharmaceutically
attractive
products,
cost-free
clean
oxygen
source,
sustainable
medium,
tolerance
broad
spectrum
functional
groups,
an
interesting
mechanism
based
on
sequential
C(sp2)-H/C(sp3)-H
bond
cleavage
insertion.
Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(12), P. 2139 - 2144
Published: March 22, 2023
The
three-component
reactions
of
enaminones,
α-diazo
esters/ketones,
and
t-butyl
nitrite
(TBN)
for
the
switchable
synthesis
isomeric
isoxazoles
have
been
realized.
catalysis
with
Cu(II)
salt
provides
3,4-disubsituted
via
[3
+
2]
cycloaddition.
On
other
hand,
Ag(I)
identical
substrates
leads
to
reversed
C3
C4
substitution
based
on
a
key
[2
1]
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(15), P. 3091 - 3096
Published: April 3, 2024
Presented
herein
is
a
novel
synthesis
of
pharmaceutically
privileged
spiroindoline
derivatives
via
cascade
reactions
N-methyl-N-nitrosoanilines
with
diazo
homophthalimides.
A
group
mechanistic
studies
disclosed
that
the
formation
product
involves
an
unusual
reaction
mode
N-methyl-N-nitrosoaniline
featuring
initial
C(sp2)–H
bond
activation/alkylation
followed
by
C(sp3)–H
activation/spiroannulation.
To
our
knowledge,
this
first
example
in
which
acts
as
C3N1
synthon
to
accomplish
formal
[4+1]
spiroannulation
participation
N-methyl
unit
rather
than
previously
reported
C2N1
undergo
[3+2]
annulation
without
unit.
In
general,
newly
developed
synthetic
protocol
features
simple
and
readily
accessible
starting
materials,
valuable
products,
unique
mechanism,
high
efficiency
atom-economy,
excellent
compatibility
diverse
functional
groups,
ready
scalability.
Molecules,
Journal Year:
2023,
Volume and Issue:
28(4), P. 1775 - 1775
Published: Feb. 13, 2023
Oximes
and
hydroxylamines
are
a
very
important
class
of
skeletons
that
not
only
widely
exist
in
natural
products
drug
molecules,
but
also
synthon,
which
have
been
used
industrial
production.
Due
to
weak
N-O
σ
bonds
oximes
hydroxylamines,
they
can
be
easily
transformed
into
other
functional
groups
by
bond
cleavage.
Therefore,
the
synthesis
N-heterocycle
using
as
nitrogen
sources
has
attracted
wide
attention.
Recent
advances
for
through
transition-metal-catalyzed
radical-mediated
cyclization
classified
type
rings
summarized.
In
this
paper,
recent
cleavage
reviewed.
We
hope
review
provides
new
perspective
on
field,
reference
develop
environmentally
friendly
sustainable
methods.
European Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
2022(46)
Published: Nov. 16, 2022
Abstract
Spiro
derivatives
are
important
scaffolding
substances
found
in
many
natural
products
and
pharmaceuticals.
In
the
last
decade,
numerous
new
approaches
based
on
multicomponent
reactions
have
been
explored
for
selective
efficient
development
of
spiro
using
various
organocatalytic
transition
metal‐based
catalytic
systems.
This
Review
discusses
pioneering
advances
field
stereoselective
preparation
derivatives.
These
include
Michael
cascade
cyclization
reactions,
cycloadditions,
diastereoselective
miscellaneous
synthesis
spiro‐hetero/carbocycles.
Advances
decade
made
it
possible
to
synthesize
compounds
with
good
excellent
stereoselectivity
under
appropriate
reaction
conditions.
However,
achieving
high
regioselectivity
several
described
remains
a
challenge.
Organocatalysts
transition‐metal‐based
catalysts
play
crucial
role
this
milestone.
Proposed
mechanisms
supporting
evidence
highlighted
Review.
The
progress
is
immense.
expected
that
synthetic
methods
will
soon
be
developed
can
widely
used
spiro‐heterocycles/carbocycles.
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(22), P. 13884 - 13896
Published: Oct. 27, 2022
Understanding
the
reaction
mechanisms,
particularly
chiral
induction
mode,
is
critical
for
development
of
new
asymmetric
catalytic
reactions.
Rhodium(III)-catalyzed
C–H
activation
en
route
to
atroposelective
[4
+
2]
annulative
coupling
with
α-diazo
β-ketoesters
has
been
realized,
affording
axially
phenanthrenes
in
good
excellent
enantioselectivity.
A
combination
experimental
and
computational
studies
revealed
a
nontraditional
stereodivergent–convergent
mode.
The
proceeded
rhodafluorene
intermediate,
followed
by
competitive,
constructive,
stereodivergent
migratory
insertions
two
Rh–C(aryl)
bonds
into
carbene
species
give
β-ketoester
intermediates.
Then,
other
bond
migratorily
inserts
ketone
carbonyl
group.
Following
this
stereodetermining
insertion,
an
ester-chelated
rhodium(III)
alkoxide
bearing
poorly
controlled
centers
well-controlled
C(sp2)–C(sp3)
axis
generated.
final
product
delivered
via
stereoconvergent
elimination
retention
axial
chirality
loss
central
chirality.