An
unprecedented
catalytic
kinetic
resolution
of
2-substituted
3-nitro-2H-chromenes
via
Rh-catalyzed
asymmetric
hydrogenation
has
been
developed
to
simultaneously
produce
a
variety
syn-chiral
3-nitro-2H-chromanes
containing
vicinal
stereogenic
centers
with
excellent
diastero-
and
enantioselectivities
[diastereomeric
ratio
(dr)
>99:1
up
99.9%
enantiomeric
excess
(ee)]
recovered
chiral
90–99.9%
ee
in
high
yields,
respectively,
achieving
selectivity
factors
1057.
Moreover,
addition
3-nitro-2H-chromanes,
this
new
approach
provides
concise,
atom-economical,
straightforward
access
anti-chiral
mammalian
target
rapamycin
(mTOR)
inhibitor,
(R)-DHM25.
Chinese Journal of Chemistry,
Год журнала:
2024,
Номер
42(15), С. 1734 - 1740
Опубликована: Март 30, 2024
Comprehensive
Summary
Axially
chiral
biaryls
represent
the
most
important
class
of
atropisomers,
and
they
widely
exist
in
natural
products
biologically
active
molecules.
They
also
constitute
a
unique
scaffold
for
ligands
catalysts
organic
synthesis.
The
development
synthetic
methods
to
obtain
such
compounds
has
received
widespread
attention,
among
which
catalytically
atroposelective
ring‐opening
configurationally
labile
represents
one
attractive
strategies.
Various
substrates
with
strained
cyclic
structures,
as
renowned
Bringmann's
lactones,
can
undergo
asymmetric
transformation
into
stable
atropisomers.
Known
advancement
primarily
relies
on
metal
catalyst
combined
well‐designed
ligands,
approaches
utilizing
organocatalysis
critical
resolution
strategy
are
notably
scarce.
In
this
study,
we
disclosed
N
‐heterocyclic
carbene
(NHC)‐catalyzed
reaction
biaryl
lactams
via
direct
nucleophilic
activation.
optimized
bulky
ensures
that
proceed
under
mild
conditions,
affording
desired
product
good
excellent
yields
atroposelectivity.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(37)
Опубликована: Май 7, 2024
The
development
of
methods
to
allow
the
selective
acylative
dynamic
kinetic
resolution
(DKR)
tetra-substituted
lactols
is
a
recognised
synthetic
challenge.
In
this
manuscript,
highly
enantioselective
isothiourea-catalysed
DKR
morpholinone
and
benzoxazinone-derived
reported.
scope
limitations
methodology
have
been
developed,
with
high
enantioselectivity
good
excellent
yields
(up
89
%,
99
:
1
er)
observed
across
broad
range
substrate
derivatives
incorporating
substitution
at
N(4)
C(2),
di-
spirocyclic
C(5)
C(6),
as
well
benzannulation
(>35
examples
in
total).
process
amenable
scale-up
on
g
laboratory
scale.
factors
leading
selectivity
probed
through
computation,
an
N-C=O⋅⋅⋅isothiouronium
interaction
identified
key
producing
ester
products
enantioenriched
form.
ACS Catalysis,
Год журнала:
2025,
Номер
15(3), С. 1973 - 2001
Опубликована: Янв. 20, 2025
Chiral
quaternary
ammonium
ion-pair
organocatalysis
has
been
widely
used
in
the
facile
synthesis
of
chiral
molecules
with
challenging
stereocenters.
Especially,
numerous
asymmetric
nucleophilic
addition
reactions
have
facilitated
this
strategy.
This
review
systematically
summarizes
additions
promoted
by
salts
past
decade.
The
content
is
organized
according
to
types
electrophiles
involved
these
catalytic
transformations.
Our
own
perspectives
on
future
development
within
highly
active
research
field
are
also
provided.
A
chiral
carbene-catalyzed
dynamic
kinetic
resolution
for
the
facile
synthesis
of
enantioenriched
dihydro-1,4-benzoxazine-2-carboxylates
is
disclosed.
The
reaction
conditions
are
mild,
and
a
diversity
substituents
well-tolerated
in
this
transformation.
In
addition,
our
methodology
also
provides
an
efficient
strategy
building
chromane-2-carboxylate
2,3-dihydro-1,4-benzodioxane-2-carboxylate.
optically
pure
products
generated
from
protocol
can
be
easily
derived
as
key
intermediates
drugs
bioactive
molecules.
An
unprecedented
catalytic
kinetic
resolution
of
2-substituted
3-nitro-2H-chromenes
via
Rh-catalyzed
asymmetric
hydrogenation
has
been
developed
to
simultaneously
produce
a
variety
syn-chiral
3-nitro-2H-chromanes
containing
vicinal
stereogenic
centers
with
excellent
diastero-
and
enantioselectivities
[diastereomeric
ratio
(dr)
>99:1
up
99.9%
enantiomeric
excess
(ee)]
recovered
chiral
90–99.9%
ee
in
high
yields,
respectively,
achieving
selectivity
factors
1057.
Moreover,
addition
3-nitro-2H-chromanes,
this
new
approach
provides
concise,
atom-economical,
straightforward
access
anti-chiral
mammalian
target
rapamycin
(mTOR)
inhibitor,
(R)-DHM25.
