Organic Letters,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 26, 2024
A
palladium-catalyzed
[2π
+
2σ]
cycloaddition
of
vinyl
bicyclo[1.1.0]butanes
with
methyleneindolinones
has
been
developed.
The
reaction
enables
the
construction
spirobicyclo[2.1.1]hexanes
bearing
an
all-carbon
quaternary
center
in
moderate
to
good
yields
excellent
diastereoselectivities.
This
method
features
a
broad
substrate
scope
functional
group
compatibility.
practical
utility
this
protocol
was
further
demonstrated
by
gram-scale
synthesis
and
postsynthetic
transformations
desired
product.
Chemical Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
We
disclose
a
method
for
silver-enabled
formal
[4π
+
2
σ
]
cycloaddition
reactions
between
bicyclobutanes
and
nitrile
imines
(generated
from
hydrazonyl
chlorides)
to
furnish
diverse
array
of
2,3-diazo-BCHepes.
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 28, 2025
The
cycloaddition
reactions
of
bicyclo[1.1.0]butanes
with
alkenes,
imines,
nitrones,
or
aziridines
have
served
as
an
efficient
platform
to
create
conformationally
restricted
saturated
bicyclic
scaffolds.
However,
the
use
readily
available
aromatics
in
such
reactions,
especially
asymmetric
manner,
remains
underexplored.
Herein,
we
report
a
highly
regio-
and
enantioselective
dearomative
[2π
+
2σ]
photocycloaddition
reaction
between
naphthalene
derivatives
bicyclo[1.1.0]butanes,
enabled
by
Gd(III)
catalysis.
Bicyclo[1.1.0]butanes
naphthalenes
adorned
diverse
array
functional
groups
are
well-tolerated
under
mild
conditions,
affording
enantioenriched
pharmaceutically
important
bicyclo[2.1.1]hexanes
30–96%
yields
81–93%
ee
12:1
→
>20:1
rr.
synthetic
versatility
this
is
further
demonstrated
facile
removal
directing
group
derivatizations
dearomatized
product.
UV–vis
absorption
spectroscopy
studies
suggest
involvement
excited
species
process.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
unknown, P. 17837 - 17849
Published: Nov. 18, 2024
The
investigation
into
the
synthesis
of
azabicyclo[3.1.1]heptanes
(azaBCHeps)
as
bioisosteres
to
flat
aza-aromatics
has
garnered
increasing
attention,
while
it
encounters
significant
challenges.
Herein,
we
have
demonstrated
In(OTf)3-catalyzed
(3
+
3)
dipolar
cyclization
bicyclo[1.1.0]butanes
(BCBs)
with
hydrazones
and
π-allyl-iridium
1,3-dipoles,
engendering
a
diverse
array
azaBCHeps.
BCBs
furnished
densely
substituted
2,3-diazabicyclo[3.1.1]heptanes
2,3-diazabicyclo[3.1.1]heptenes
under
nitrogen
oxygen
atmospheres,
respectively.
A
combination
experimental
computational
investigations
lends
robust
support
for
proton-transfer-interposed
sequential
mechanism.
More
importantly,
by
integrating
In(OTf)3/iridium
relay
catalysis,
enantiopure
2-azabicyclo[3.1.1]heptanes
were
constructed
through
aza-π-allyl-iridium
in
situ
generated
from
N-allyl
carbonates.
Both
methodologies
exhibit
mild
reaction
conditions
good
tolerance
various
functional
groups.
Moreover,
copious
derivatization
products
highlights
utility
newly
synthesized
heterobicyclic
motifs
versatile
building
blocks
synthetic
chemistry.
ACS Catalysis,
Journal Year:
2024,
Volume and Issue:
14(24), P. 18799 - 18809
Published: Dec. 11, 2024
Transition-metal-catalyzed
cycloaddition
reactions
of
strained
small-ring
compounds
are
powerful
methods
for
constructing
carbo-
and
heterocyclic
structures
medicinal
interest.
However,
the
application
this
strategy
to
bicyclo[1.1.0]butanes
(BCBs),
which
among
most
carbocycles
known,
remains
underdeveloped.
Herein,
we
report
vinylbicyclo[1.1.0]butane
(VBCB)
as
a
platform
synthon
palladium-catalyzed
formal
[2σ+2π]
with
various
2π-components,
enabling
synthesis
BCHs,
oxa-BCHs,
aza-BCHs
under
identical
reaction
conditions.
The
zwitterionic
π-allyl-Pd
species
generated
through
activation
VBCBs
is
key
circumventing
potential
carbene
reactivity
serves
common
intermediate
cycloadditions
diverse
2π-systems,
including
alkenes,
aldehydes,
ketones,
imines.
Notably,
by
utilizing
Pd2(dba)3
an
anthracene-derived
Trost
ligand,
wide
array
BCHs
bearing
two
vicinal
chiral
centers
has
been
prepared
in
highly
diastereo-,
enantioselective
manner.
generality
practicality
method
have
demonstrated
broad
substrate
scope,
scale-up
reactions,
versatile
transformation
multiple
functional
groups
into
BCH
scaffolds.
Preliminary
mechanistic
studies
support
formation
species.
Chemical Communications,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
Herein
we
report
a
simple
BF
3
-catalyzed
cycloaddition
of
dihydropyridines
with
bicyclobutanes
for
the
expedient
synthesis
novel
three-dimensional
azacycle-fused
bicyclo[2.1.1]hexane
scaffolds.
