RSC Advances,
Год журнала:
2023,
Номер
13(51), С. 36293 - 36300
Опубликована: Янв. 1, 2023
An
exo-selective
Diels-Alder
(exo-DA)
reaction
in
which
the
formed
diastereomer
is
different
from
that
conventional
endo-selective
(endo-DA)
was
developed,
involves
a
dual-functional
Brønsted
acid
as
catalyst
and
not
only
dienophile
(vinylquinoline)
but
also
an
acyclic
diene
(dienylcarbamate)
having
sterically
less
demanding
substituent.
Factors
necessary
for
achieving
exo-DA
were
extracted
through
exhaustive
computational
search
of
corresponding
transition
states,
relative
orientation
firmly
defined
by
hydrogen
bonding
interactions
with
catalyst.
It
experimentally
verified
combined
use
catalyst,
such
phosphoric
acid,
conformationally
restricted
(dienylcarbamate),
realized
introduction
substituent
at
2-position
unit,
key
to
reaction.
A
catalytic
enantioselective
attempted
using
chiral
gave
rise
exo-adduct
fairly
good
enantioselectivity.
ACS Catalysis,
Год журнала:
2024,
Номер
14(18), С. 13792 - 13799
Опубликована: Сен. 2, 2024
Chiral
2,3-dihydro-4H-imidazol-4-ones
are
key
motifs
in
both
synthetic
and
biological
chemistry.
However,
their
accessibility
is
classically
limited
to
optical
resolution
of
enantioenriched
products.
Herein,
we
report
the
catalytic
asymmetric
synthesis
these
4-imidazolones
via
cyclocondensation
N-silyl
iminoesters
N-unprotected
ketimines
using
a
chiral
phosphoric
acid
catalyst.
The
enantioselective
reaction
has
broad
substrate
tolerance
maintains
high
yields
enantioselectivities
(up
99%,
99%
ee).
Furthermore,
dimerization
afford
various
imidazolones
was
performed
same
system
95%,
obtained
products
were
easily
converted
into
significant
heterocyclic
molecules
such
as
imidazoles,
imidazolidines,
nitrones.
Experimental
results
density
functional
theory
(DFT)
calculations
revealed
plausible
mechanism
origin
induction.
The Journal of Organic Chemistry,
Год журнала:
2022,
Номер
87(23), С. 15806 - 15819
Опубликована: Окт. 31, 2022
A
protocol
for
the
stereodivergent
pentafluoroethylation
of
N-sulfinylimines
using
HFC-125
with
KHMDS/triglyme
has
been
developed.
Both
diastereomers
pentafluoroethylated
amines
can
be
selectively
synthesized
based
on
presence
or
absence
triglyme.
This
additive-controlled
allows
cryptate
to
a
straightforward
and
cheap
alternative
previously
reported
base-controlled
trifluoromethylation
potassium
hexamethyldisilazide
(KHMDS)
versus
P4-tBu.
Organic Letters,
Год журнала:
2023,
Номер
25(37), С. 6813 - 6817
Опубликована: Сен. 13, 2023
A
catalytic
enantioselective
Friedel-Crafts
reaction
of
various
heteroaromatic
compounds
with
glyoxals
has
been
developed.
In
the
presence
a
chiral
oxazaborolidinium
ion
catalyst,
provided
α-hydroxyketones
in
high
yield
(up
to
96%)
excellent
enantioselectivity
>99%
ee).
The
synthetic
utility
this
method
was
illustrated
by
conversion
products
derivatives
such
as
1,2-diol
and
β-amino
alcohol.
RSC Advances,
Год журнала:
2023,
Номер
13(51), С. 36293 - 36300
Опубликована: Янв. 1, 2023
An
exo-selective
Diels-Alder
(exo-DA)
reaction
in
which
the
formed
diastereomer
is
different
from
that
conventional
endo-selective
(endo-DA)
was
developed,
involves
a
dual-functional
Brønsted
acid
as
catalyst
and
not
only
dienophile
(vinylquinoline)
but
also
an
acyclic
diene
(dienylcarbamate)
having
sterically
less
demanding
substituent.
Factors
necessary
for
achieving
exo-DA
were
extracted
through
exhaustive
computational
search
of
corresponding
transition
states,
relative
orientation
firmly
defined
by
hydrogen
bonding
interactions
with
catalyst.
It
experimentally
verified
combined
use
catalyst,
such
phosphoric
acid,
conformationally
restricted
(dienylcarbamate),
realized
introduction
substituent
at
2-position
unit,
key
to
reaction.
A
catalytic
enantioselective
attempted
using
chiral
gave
rise
exo-adduct
fairly
good
enantioselectivity.
