European Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
27(24)
Published: April 22, 2024
Abstract
The
electrophilic
activation
of
2
H
‐azirines
with
triflic
anhydride
(Tf
O)
for
an
addition/cyclization
reaction
producing
2‐aryl‐pyrido[2,3‐
b
]pyrazines
regioselectively
is
described.
This
proceeds
via
nucleophilic
addition
3‐amino‐2‐fluoropyridines
onto
1‐trifloyl‐aziridin‐2‐yl
triflates
and
subsequent
cyclization
S
N
Ar.
Desulfonylation
oxidation
provides
a
single
regioisomer
the
aza‐bicyclic
heterocycle
after
treatment
Et
3
N.
Optimization
conditions
lead
to
range
in
isolated
yields
20
%
60
%.
Chinese Journal of Chemistry,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Nov. 20, 2024
Comprehensive
Summary
Indolizine
is
a
nitrogen‐containing
heterocycle
with
strong
aromaticity,
possessing
delocalized
10π‐electron
system.
Based
on
the
indolizine
scaffolds,
numerous
molecules
biological
activity
and
organic
functional
materials
have
been
synthesized.
Since
2016,
over
110
papers
published
synthesis
of
but
reviews
synthesizing
scaffolds
incomplete
not
up‐to‐date.
Herein,
from
perspective
structure
combination
pyrrole
pyridine
ring,
we
focus
construction
through
diversity
starting
substrates,
including
derivatives
(N1‐substituted
pyridinium
salt
derivatives,
C2‐substituted
N1‐
C2‐free
substituted
derivatives),
unoriginal
ring
substrates.
Furthermore,
corresponding
reaction
mechanisms
synthetic
methodologies
are
also
elaborated.
Therefore,
this
review
only
paves
way
for
provides
insight
into
exploring
new
modes
constructing
heterocycles.
Key
Scientists
was
discovered
by
Angeli
in
1890
first
prepared
Scholtz
1912
α‐picoline
acetic
anhydride.
A
general
approach
developed
Chichibabin
1927,
that
practical
value
preparation
2‐alkyl‐
or
2‐arylindolizines.
The
closure
quaternary
halides.
At
begining
21st
century,
Basavaiah
introduced
dimension
Baylis‐Hillman
chemistry
leading
to
novel
facile
convenient
methodology
one‐pot
operation.
In
2010,
Barluenga
reported
Cu(I)‐catalyzed
regioselective
[3+2]
cyclization
unsubstituted
pyridines
toward
alkenyldiazoacetates
functionalized
successful
example
metal‐catalyzed
π‐deficient
heterocyclic
system
alkenyldiazo
compounds.
2019
2022,
Xi
Liu
exploited
methods
non‐pyridine
as
synthesize
indolizines,
respectively.
Guo
an
environmentally
benign
electrooxidative
formyl‐
acyl‐substituted
indolizines.
The Journal of Organic Chemistry,
Journal Year:
2023,
Volume and Issue:
89(1), P. 373 - 378
Published: Dec. 14, 2023
A
highly
efficient
and
regioselective
method
for
constructing
functionalized
conjugated
enals
via
the
Tf2O-mediated
tandem
reaction
of
enaminones
with
thiophenols
has
been
described.
Chain
products
excellent
stereoselectivity
could
be
obtained
through
substrate
regulation.
Additionally,
a
feasible
synthesizing
β-naphthalaldehydes
PhSO2Na/DABCO
promoting
hydrogen
atom
transfer
process
also
reported
here.
Mechanism
studies
have
shown
that
2-formyl
vinyl
triflate
8
sulfonylated
enal
9
were
key
intermediates
in
this
process.
Organic Chemistry Frontiers,
Journal Year:
2024,
Volume and Issue:
11(13), P. 3685 - 3691
Published: Jan. 1, 2024
A
new
method
for
the
synthesis
of
seven-membered
heterocycle-fused
indolizine
scaffolds
from
2-(1-alkynyl-cyclopropyl)pyridines
and
nitrones
under
catalysis
PPh
3
AuNTf
2
.
European Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
27(24)
Published: April 22, 2024
Abstract
The
electrophilic
activation
of
2
H
‐azirines
with
triflic
anhydride
(Tf
O)
for
an
addition/cyclization
reaction
producing
2‐aryl‐pyrido[2,3‐
b
]pyrazines
regioselectively
is
described.
This
proceeds
via
nucleophilic
addition
3‐amino‐2‐fluoropyridines
onto
1‐trifloyl‐aziridin‐2‐yl
triflates
and
subsequent
cyclization
S
N
Ar.
Desulfonylation
oxidation
provides
a
single
regioisomer
the
aza‐bicyclic
heterocycle
after
treatment
Et
3
N.
Optimization
conditions
lead
to
range
in
isolated
yields
20
%
60
%.
