The Michael donor–acceptor reactivity of curcumins in the synthesis of diverse multi-functional scaffolds
Organic & Biomolecular Chemistry,
Год журнала:
2024,
Номер
22(7), С. 1346 - 1359
Опубликована: Янв. 1, 2024
Curcumin
and
its
analogs,
display
Michael
donor–acceptor
ability
with
various
reactants
in
the
presence
of
bases,
Lewis
acids
catalysts,
under
conventional,
microwave
mechanochemical
conditions
generate
diverse
synthetic
scaffolds.
Язык: Английский
Mechanistic Study on the Asymmetric Cascade Michael Addition of Alkynone and Oxindole Catalyzed by Chiral Guanidine
The Journal of Organic Chemistry,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 26, 2025
Density
functional
theory
(DFT)
calculations
with
the
M06-2X-D3
were
used
to
get
mechanistic
investigation
and
stereoselectivity
of
cascade
Michael
addition
alkynone
oxindole,
catalyzed
by
a
chiral
guanidine-amide
compound.
The
reaction
proceeded
through
two-step
synergistic
process
involving
sequential
C–C
C–O
bond
formation,
together
an
H-shift.
Because
high
energy
barriers
33.5
kcal
mol−1
(for
construction)
41.3
mol–1
construction),
was
difficult
proceed
without
catalyst.
guanidine
catalyst
facilitated
generation
enolized
oxindole
species
nucleophilicity,
activating
both
enolate
via
ion-pairing
multiple
hydrogen
bonding,
significantly
lowering
activation
barriers.
combination
unit
sulfonamide
backbone
created
excellent
semiclosed
environment,
promoting
asymmetric
induction.
Due
steric
effects
from
ortho-
para-substituted
iPr
groups
in
SO2Ar,
bulky
Cy
group,
backbone,
SS-configuration
spirocyclization
product
enantio-
diastereoselectivity
formed
predominantly.
E/Z
selectivity
formation
key
α,β-unsaturated
ketone
intermediate
influenced
catalyst-substrate
interactions.
Extension
alkyl
chain
at
3-position
substrate
led
more
difficult,
hindering
construction
spirooxindoles.
Язык: Английский
Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates
Beilstein Journal of Organic Chemistry,
Год журнала:
2024,
Номер
20, С. 2016 - 2023
Опубликована: Авг. 15, 2024
A
cascade
inter-intramolecular
double
Michael
strategy
for
the
synthesis
of
highly
functionalized
cyclohexanones
from
curcumins
and
arylidenemalonates
is
reported.
This
works
in
presence
aqueous
KOH
using
TBAB
as
a
suitable
phase
transfer
catalyst
at
room
temperature.
The
are
formed
major
products
moderate
to
excellent
yields
with
complete
diastereoselectivity
most
cases.
triple
adduct,
tetrahydrochromen-4-one,
also
side
product
few
cases
diastereoselectivity.
Язык: Английский