Angewandte Chemie,
Journal Year:
2023,
Volume and Issue:
135(23)
Published: April 3, 2023
Abstract
σ‐Lewis
base‐catalyzed
regio‐
and
enantioselective
aza‐Morita–Baylis–Hillman
(MBH)
reaction
of
α,β,γ,δ‐unsaturated
systems
remains
a
challenge
due
to
the
intrinsic
covalent
activation
mode.
Here
we
demonstrate
that
Pd
0
complex
can
mediate
dehydrogenative
γ,δ‐unsaturated
compounds
give
corresponding
electron‐poor
dienes,
which
further
undergo
δ‐regioselective
umpolung
Friedel–Crafts‐type
addition
imines
via
auto‐tandem
‐π‐Lewis
base
catalysis.
After
β‐H
elimination
in
situ
formed
II
‐complexes,
unprecedented
chemically
inverse
aza‐MBH‐type
adducts
are
finally
furnished
with
fair
outstanding
enantioselectivity,
diversity
functional
groups
both
ketimine
aldimine
acceptors
be
well
tolerated.
Moreover,
switchable
α‐regioselective
normal
also
realized
by
tuning
catalytic
conditions,
whereas
moderate
good
enantioselectivity
low
excellent
Z
/
E
‐selectivity
is
attained.
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
89(8), P. 5883 - 5895
Published: April 10, 2024
By
creating
an
unsymmetric
double
Michael
acceptor
1,
we
were
able
to
synthesize
the
nonaromatic-fused
bicyclic
furo[2,3-b]pyrrole
nucleus
using
a
domino
Michael/oxa-Michael
reaction.
Adopting
benzoyl
acetonitrile
2d
(CN
as
electron-withdrawing
group)
substrate,
discovered
(DHQ)2AQN-catalyzed
method
for
high
diastereo-
and
enantioselectivity
of
those
products.
The
reaction
path
has
been
determined
by
isolating
intermediates,
density
functional
theory
calculations
support
these
findings.
Beyond
providing
synthetic
approach,
this
work
illustrated
compounds'
possible
use
in
antitumor
activity.
Angewandte Chemie,
Journal Year:
2024,
Volume and Issue:
136(44)
Published: Aug. 6, 2024
Abstract
The
transition
metal‐catalyzed
asymmetric
hydro‐functionalization
of
1,3‐dienes
has
been
well
explored,
but
most
reactions
focus
on
electron‐neutral
substrates
in
an
intermolecular
manner.
Here
we
first
demonstrate
that
readily
available
2,4‐dienyl
hydrazones
and
oximes
can
be
efficiently
utilized
the
hydro‐cyclization
reaction
under
co‐catalysis
a
Brønsted
acid
chiral
palladium
complex,
furnishing
multifunctional
dihydropyrazones
dihydroisoxazoles,
respectively.
Diverse
substitution
patterns
for
both
types
electron‐deficient
diene
compounds
are
tolerated,
corresponding
heterocycles
were
generally
constructed
with
moderate
to
excellent
enantioselectivity,
which
elaborated
access
products
higher
molecular
complexity
diversity.
Control
experiments
density
functional
theory
calculations
support
α‐regioselective
protonation
dienyl
by
concurrent
π‐Lewis
base
activation
Pd
0
complex
is
energetically
favoured
formation
active
π‐allylpalladium
intermediates,
outer‐sphere
allylic
amination
or
etherification
mode
adopted
deliver
observed
cyclized
enantioselectively.
