Chemical Science,
Journal Year:
2021,
Volume and Issue:
12(33), P. 11181 - 11190
Published: Jan. 1, 2021
This
study
describes
general
methods
for
the
enantioselective
syntheses
of
pharmaceutically
relevant
1-aryl-2-heteroaryl-
and
1,2-diheteroarylcyclopropane-1-carboxylates
through
dirhodium
tetracarboxylate-catalysed
asymmetric
cyclopropanation
vinyl
heterocycles
with
aryl-
or
heteroaryldiazoacetates.
The
reactions
are
highly
diastereoselective
high
induction
could
be
achieved
using
either
(R)-pantolactone
as
a
chiral
auxiliary
tetracarboxylate
catalysts.
For
meta-
para-substituted
heteroaryldiazoacetates
optimum
catalyst
was
Rh2(R-p-Ph-TPCP)4.
In
case
ortho-substituted
heteroaryldiazoacetates,
Rh2(R-TPPTTL)4.
reaction
substrates,
2-chloropyridine
required
an
additive
in
presence
4
Å
molecular
sieves
1,1,1,3,3,3-hexafluoroisopropanol
(HFIP).
Under
optimized
conditions,
conducted
variety
heterocycles,
such
pyridines,
pyrazines,
quinolines,
indoles,
oxadiazoles,
thiophenes
pyrazoles.
ACS Catalysis,
Journal Year:
2022,
Volume and Issue:
12(6), P. 3309 - 3316
Published: Feb. 25, 2022
The
reduction
of
epoxides
is
a
powerful
tool
to
access
anti-Markovnikov
alcohols,
but
reported
methods
are
poorly
compatible
with
strongly
electronically
deactivated
substrates.
Here,
we
describe
general
method
for
the
linear-selective
styryl
oxides
incorporating
strong
electron-withdrawing
groups.
remains
more
traditional
epoxide
motifs,
such
as
aliphatic
and
electron-rich
styrene
oxides.
Other
(hetero)cycles
oxetanes,
tetrahydrofurans,
aziridines,
cyclopropanes
can
also
be
reductively
opened.
This
user-friendly
reaction
relies
on
combination
Brønsted
acid
catalyst
hexafluoroisopropanol
solvent,
thus,
in
contrast
existing
methods,
it
does
not
require
anhydrous
reagents
or
an
inert
atmosphere.
generated
primary
alcohols
conveniently
functionalized
situ
by
dehydrative
Friedel–Crafts
arylation
without
preactivation.
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
89(13), P. 9427 - 9439
Published: June 21, 2024
A
mechanochemical
synthesis
of
1,2-disubstituted
benzimidazoles
from
donor-acceptor
cyclopropyl
ketones
and
1,2-diaminoarenes
under
metal-free
solventless
conditions
is
reported.
The
reaction
does
not
require
inert
promoted
by
a
stoichiometric
amount
1,1,1,3,3,3-hexafluoroisopropanol.
This
cascade
involves
ring-opening,
cyclization,
retro-Mannich
with
aryl
1,2-diamines.
Compared
to
its
solution-phase
counterpart,
this
approach
shows
fast
reactivity
(24
vs
1.5
h).
Mechanistic
investigations
electrospray
ionization
mass
spectrometry
helped
us
propose
the
mechanism.
Angewandte Chemie International Edition,
Journal Year:
2020,
Volume and Issue:
60(2), P. 946 - 953
Published: Sept. 21, 2020
Pyrrolidine
and
piperidine
derivatives
bearing
halide
functional
groups
are
prevalent
building
blocks
in
drug
discovery
as
halides
can
serve
an
anchor
for
post-modifications.
In
principle,
one
of
the
simplest
ways
to
build
these
frameworks
is
haloamination
alkenes.
While
progress
has
been
made
this
field,
notably
with
development
enantioselective
versions,
reaction
still
fraught
limitations
terms
reactivity.
Besides,
a
major
question
remaining
understand
mechanism
at
work.
The
formation
haliranium
intermediate
typically
mentioned,
but
limited
mechanistic
evidence
supports
it.
Reported
here
efficient
metal-
oxidant-free
protocol
achieve
haloamidation
olefins,
promoted
by
hexafluoroisopropanol,
along
DFT
investigation
mechanism.
These
findings
should
guide
future
more
complex
transformations
field
halofunctionalization.
Organic Letters,
Journal Year:
2020,
Volume and Issue:
23(2), P. 329 - 333
Published: Dec. 29, 2020
An
efficient
asymmetric
halogenation
of
cyclic
diaryliodonium
salts
is
demonstrated,
which
gives
access
to
a
wide
range
axially
chiral
2,2′-dihalobiaryls
in
good
excellent
yields
and
with
enantioselectivities.
The
use
CuX
bisoxazoline
ligand
tetrabutylammonium
halides
the
unique
solvent
hexafluoroisopropanol
(HFIP)
led
best
results
process.
can
be
transformed
into
number
enantiopure
ligands
that
could
potentially
useful
catalysis.
Chemical Science,
Journal Year:
2021,
Volume and Issue:
12(33), P. 11181 - 11190
Published: Jan. 1, 2021
This
study
describes
general
methods
for
the
enantioselective
syntheses
of
pharmaceutically
relevant
1-aryl-2-heteroaryl-
and
1,2-diheteroarylcyclopropane-1-carboxylates
through
dirhodium
tetracarboxylate-catalysed
asymmetric
cyclopropanation
vinyl
heterocycles
with
aryl-
or
heteroaryldiazoacetates.
The
reactions
are
highly
diastereoselective
high
induction
could
be
achieved
using
either
(R)-pantolactone
as
a
chiral
auxiliary
tetracarboxylate
catalysts.
For
meta-
para-substituted
heteroaryldiazoacetates
optimum
catalyst
was
Rh2(R-p-Ph-TPCP)4.
In
case
ortho-substituted
heteroaryldiazoacetates,
Rh2(R-TPPTTL)4.
reaction
substrates,
2-chloropyridine
required
an
additive
in
presence
4
Å
molecular
sieves
1,1,1,3,3,3-hexafluoroisopropanol
(HFIP).
Under
optimized
conditions,
conducted
variety
heterocycles,
such
pyridines,
pyrazines,
quinolines,
indoles,
oxadiazoles,
thiophenes
pyrazoles.
