Two
different
cascade
pathways
to
access
spirobutenolides
were
achieved
based
on
the
substrate-controlled
regioselectivity
of
deconjugated
butenolides.
A
new
class
functional
butenolides
was
designed
and
exhibited
superior
γ-regioselectivity
in
vinylogous
Michael/Michael
reactions
with
cinnamaldehydes.
The
aryl-substituted
cinnamaldehydes
underwent
a
Michael/Michael/aldol/dehydration
process
induced
by
double
α-regioselectivities.
Both
conjugated
could
be
obtained
good
yields
excellent
enantioselectivities.
Chemical Science,
Год журнала:
2023,
Номер
14(39), С. 10806 - 10811
Опубликована: Янв. 1, 2023
Spirocyclic
butyrolactones
and
butenolides
are
widespread
structural
motifs
in
bioactive
substances.
Despite
their
prevalence,
a
simple
method
ensuring
direct
preparation
from
exocyclic
alkenes,
ideally
late-stage
context,
remains
elusive.
Herein,
we
report
aminolactone
formation
using
unactivated
alkenes
which
addresses
this
gap,
employing
cheap
readily
available
reactants.
The
relies
on
the
hijacking
of
cationic
aminoalkylation
pathway
affords
(spiro)aminolactones
with
excellent
functional
group
tolerance
chemoselectivity.
synthetic
versatility
products
is
demonstrated
through
range
transformations,
notably
exploiting
stereospecific
rearrangement
chemistry
to
produce
sterically
congested
scaffolds.
Organic Letters,
Год журнала:
2023,
Номер
25(40), С. 7446 - 7450
Опубликована: Окт. 3, 2023
The
synthesis
of
heretofore
unknown
γ-spirobutenolides
has
been
achieved
via
an
m-CPBA-mediated
oxidation
β-furyl
amides.
reaction
employs
a
tethered
amide,
ostensibly
poorly
reactive
carbonyl,
as
nontraditional
nucleophile
resulting
in
spirolactone
formation
and
concurrent
amide
cleavage.
transformation
exhibits
functional
group
tolerance
compatibility
with
complex
compounds.
In
situ
1H
NMR
spectroscopic
studies
reveal
the
identities
key
intermediates
oxidation–spirolactonization–oxidation
cascade,
suggesting
plausible
mechanistic
pathway.
distinct
diastereofaces
electrophilic
butenolide
product
may
be
used
for
diastereoselective
cycloaddition
conjugate
addition
reactions.
Two
different
cascade
pathways
to
access
spirobutenolides
were
achieved
based
on
the
substrate-controlled
regioselectivity
of
deconjugated
butenolides.
A
new
class
functional
butenolides
was
designed
and
exhibited
superior
γ-regioselectivity
in
vinylogous
Michael/Michael
reactions
with
cinnamaldehydes.
The
aryl-substituted
cinnamaldehydes
underwent
a
Michael/Michael/aldol/dehydration
process
induced
by
double
α-regioselectivities.
Both
conjugated
could
be
obtained
good
yields
excellent
enantioselectivities.
