Molecules,
Journal Year:
2023,
Volume and Issue:
28(13), P. 5014 - 5014
Published: June 27, 2023
In
this
study,
we
report
the
synthesis
of
unsubstituted
1,2-benzothiazines
through
a
redox-neutral
Rh(III)-catalyzed
C–H
activation
and
[4+2]-annulation
S–aryl
sulfoximines
with
vinylene
carbonate.
Notably,
introduction
an
N-protected
amino
acid
ligand
significantly
enhances
reaction
rate.
The
key
aspect
process
is
utilization
carbonate
as
oxidizing
acetylene
surrogate
efficient
transfer
agent.
This
enables
cyclization
sulfoximine
motifs,
successfully
forming
diverse
array
1,2-benzothiazine
derivatives
in
moderate
to
good
yields.
Importantly,
study
highlights
potential
reactions
for
optically
pure
high
enantiomeric
purity.
European Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
2022(19)
Published: April 21, 2022
Abstract
A
rhodium‐catalyzed
C−H
activation/annulation
of
N
‐aryl‐pyrazolidinones
with
vinylene
carbonate
was
developed.
The
utilization
as
the
acetylene
surrogate
furnished
successful
construction
non‐substituted
5,6‐pyrazolo[1,2‐
a
]cinnoline
derivatives,
which
are
difficult
to
synthesize
through
other
procedures.
In
this
work,
series
variously
substituted
pyrazolo[1,2‐
]cinnolines
were
obtained
in
yields
up
98
%
broad
substrate
scope
and
excellent
selectivity.
Moreover,
external
oxidants
not
required
protocol
H
2
O
CO
clean
by‐products.
Angewandte Chemie International Edition,
Journal Year:
2022,
Volume and Issue:
62(1)
Published: Nov. 4, 2022
Abstract
A
multicomponent
annulation
that
proceeds
by
imine
directed
Cp*Rh
III
‐catalyzed
N−H
functionalization
is
disclosed.
The
transformation
affords
piperazinones
displaying
a
range
of
functionality
and
the
first
example
transition
metal‐catalyzed
functionalization.
broad
readily
available
α‐amino
amides,
including
those
derived
from
glycine,
α‐substituted,
α,α‐disubstituted
amino
acids,
were
effective
inputs
enabled
incorporation
variety
acid
side
chains
with
minimal
racemization.
Branched
unbranched
alkyl
aldehydes
various
stabilized
diazo
compounds
also
efficient
reactants.
piperazinone
products
further
modified
through
transformations.
Mechanistic
studies,
X‐ray
crystallographic
characterization
catalytically
competent
five‐membered
rhodacycle
amide
nitrogen
chelation,
provide
support
for
proposed
mechanism.
The Journal of Organic Chemistry,
Journal Year:
2022,
Volume and Issue:
87(15), P. 9864 - 9874
Published: July 14, 2022
An
efficient
and
facile
approach
for
the
synthesis
of
quinazolin-4(3H)-ones
via
reaction
quinazoline-3-oxides
with
primary
amines
is
described.
This
demonstrated
to
be
applicable
a
broad
range
substrates
proceeds
efficiently
under
metal-free
mild
conditions
employing
easily
available
tert-butyl
hydroperoxide
as
oxidant.
Remarkably,
3-(2-(1H-indol-3-yl)
ethyl)quinazolin-4(3H)-one
3w,
which
was
conveniently
obtained
by
this
process
in
70%
yield,
an
excellent
precursor
bioactive
evodiamine
rutaempine.
Molecules,
Journal Year:
2023,
Volume and Issue:
28(13), P. 5014 - 5014
Published: June 27, 2023
In
this
study,
we
report
the
synthesis
of
unsubstituted
1,2-benzothiazines
through
a
redox-neutral
Rh(III)-catalyzed
C–H
activation
and
[4+2]-annulation
S–aryl
sulfoximines
with
vinylene
carbonate.
Notably,
introduction
an
N-protected
amino
acid
ligand
significantly
enhances
reaction
rate.
The
key
aspect
process
is
utilization
carbonate
as
oxidizing
acetylene
surrogate
efficient
transfer
agent.
This
enables
cyclization
sulfoximine
motifs,
successfully
forming
diverse
array
1,2-benzothiazine
derivatives
in
moderate
to
good
yields.
Importantly,
study
highlights
potential
reactions
for
optically
pure
high
enantiomeric
purity.
