Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 28, 2025
Asymmetric
synthesis
presents
many
challenges,
with
the
selective
formation
of
chiral
bridged
polyheterocycles
being
a
notable
example.
Cycloadditions
using
bicyclo[1.1.0]butanes
(BCB)
offer
promising
solution
along
those
lines,
yet,
despite
significant
advances
in
that
emerging
area,
asymmetric
control
has
remained
limited
thus
far.
Here,
we
describe
an
organocatalytic,
enantioselective
formal
(3
+
3)-cycloaddition
BCBs
1H-indol-3-yl((hetero)aryl)methanol
derivatives.
This
approach
enables
rapid
and
efficient
tetrahydro-1H-1,3-methanocarbazole
derivatives
(34
examples)
from
readily
available
starting
materials,
very
good
stereochemical
(up
to
98:2
er).
Successful
scale-up
experiments
product
modification
demonstrated
potential
this
methodology.
Control
DFT
calculations
provide
insights
into
mechanistic
pathway.
Synthesis,
Journal Year:
2022,
Volume and Issue:
54(14), P. 3125 - 3141
Published: Feb. 24, 2022
Abstract
This
review
summarizes
recent
developments
in
the
area
of
Brønsted
acid
catalyzed,
enantioselective
cycloadditions
ortho-quinone
methides,
methide
imines
as
well
heterocyclic
indole-
and
pyrrole-based
methides.
In
a
straightforward
single-step
transformation
complex
polycyclic
N-
O-heterocyclic
scaffolds
are
accessible,
with
typically
good
yields
excellent
stereocontrol,
from
simple
benzyl
heterobenzyl
alcohols
upon
acid-catalyzed
dehydration.
The
transient
precursors
hydrogen-bonded
to
chiral
which
controls
enantioselectivity
process.
1
Introduction
2
Cycloadditions
ortho-Quinone
Methides
2.1
Acid
Catalyzed
Processes
2.2
Cooperative
Acid/Transition-Metal-Catalyzed
3
Methide
Imines
4
Indolyl-3-methides
5
Indolyl-2-methides
5.1
5.2
6
Pyrrolyl-2-methides
7
Pyrrolyl-3-methides
8
Conclusions
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(21), P. 11745 - 11753
Published: May 19, 2023
Herein,
we
report
a
highly
efficient
synthesis
of
enantioenriched
aza-[3.3.1]-bicyclic
enamines
and
ketones,
class
structural
cores
in
many
natural
products,
via
asymmetric
dearomatization
indoles
with
azodicarboxylates.
The
reaction
is
initiated
by
electrophilic
amination
followed
aza-Prins
cyclization/phenonium-like
rearrangement.
A
newly
developed
fluorine-containing
chiral
phosphoric
acid
displays
excellent
activity
promoting
this
cascade
reaction.
absence
or
presence
water
as
the
additive
directs
pathway
toward
either
enamine
ketone
products
high
yields
(up
to
93%)
enantiopurity
98%
ee).
Comprehensive
density
functional
theory
(DFT)
calculations
reveal
energy
profile
origins
enantioselectivity
water-induced
chemoselectivity.
The Journal of Organic Chemistry,
Journal Year:
2024,
Volume and Issue:
89(2), P. 1249 - 1255
Published: Jan. 4, 2024
In
this
study,
the
AgOAc/ThioClickFerrophos
(TCF)
complex
was
used
to
successfully
catalyze
asymmetric
[3
+
2]
cycloaddition
between
glycine
imino
esters
and
CO2Me-appended
α-alkylidene
succinimides
afford
spiropyrrolidines
in
good
yields
with
high
diastereo-
enantioselectivities
(up
95%
ee).
The
silver/TCF
afforded
endo-(2,5-cis)
cycloadducts
contrast
previous
exo′-(2,5-trans)
selective
reaction
ylidene-2,3-dioxopyrrolidine.
A
wide
variety
of
bearing
electron-donating
electron-withdrawing
groups
on
phenyl
heteroaryl
substrates
were
utilized
reaction.
scope
investigated,
which
revealed
that
substituents
α-benzylidene
derivatives
had
negligible
effect
product
yield
stereoselectivity,
could
be
efficiently
as
dipolarophiles.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(22)
Published: April 2, 2024
Spiroaminals
represent
novel
structural
motifs
prevalent
in
diverse
natural
products
and
biologically
active
molecules.
Achieving
their
enantioselective
synthesis
is
a
highly
desirable
challenging
task
synthetic
endeavors
due
to
intricate
molecular
frameworks.
Herein,
we
accomplished
the
first
stereodivergent
construction
of
spiroaminals
using
chiral
bifunctional
organocatalyzed
intramolecular
1,2-addition
followed
by
an
oxa-Michael
addition
cascade
high
atom
step
economical
pathway.
A
proper
modulation
cinchona-derived
squaramide
catalysts
efficiently
provided
access
all
possible
stereoisomers
with
yield,
diastereoselectivity,
excellent
enantioselectivity
while
displaying
broad
substrate
tolerance.
Additionally,
validated
scalability
reaction
demonstrated
variable
spiroaminal
scaffolds,
confirming
viability
our
protocol.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(28), P. 15036 - 15042
Published: July 10, 2023
A
catalytic
protio-semipinacol
ring-expansion
reaction
has
been
developed
for
the
highly
enantioselective
conversion
of
tertiary
vinylic
cyclopropyl
alcohols
into
cyclobutanone
products
bearing
α-quaternary
stereogenic
centers.
The
method
relies
on
cocatalytic
effect
a
chiral
dual-hydrogen-bond
donor
(HBD)
with
hydrogen
chloride.
Experimental
evidence
is
provided
stepwise
mechanism
where
protonation
alkene
generates
short-lived,
high-energy
carbocation,
which
followed
by
C–C
bond
migration
to
deliver
enantioenriched
product.
This
research
applies
strong
acid/chiral
HBD
cocatalysis
weakly
basic
olefinic
substrates
and
lays
foundation
further
investigations
reactions
involving
cationic
intermediates.
Chemical Reviews,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 18, 2025
Chiral
phosphoric
acids
(CPAs)
have
emerged
as
highly
effective
Brønsted
acid
catalysts
in
an
expanding
range
of
asymmetric
transformations,
often
through
novel
multifunctional
substrate
activation
modes.
Versatile
and
broadly
appealing,
these
benefit
from
modular
tunable
structures,
compatibility
with
additives.
Given
the
unique
types
noncovalent
interactions
(NCIs)
that
can
be
established
between
CPAs
various
reactants─such
hydrogen
bonding,
aromatic
interactions,
van
der
Waals
forces─it
is
unsurprising
catalyst
systems
become
a
promising
approach
for
accessing
diverse
chiral
product
outcomes.
This
review
aims
to
provide
in-depth
exploration
mechanisms
by
which
impart
stereoselectivity,
positioning
NCIs
central
feature
connects
broad
spectrum
catalytic
reactions.
Spanning
literature
2004
2024,
it
covers
nucleophilic
additions,
radical
atroposelective
bond
formations,
highlighting
applicability
CPA
organocatalysis.
Special
emphasis
placed
on
structural
mechanistic
features
govern
CPA-substrate
well
tools
techniques
developed
enhance
our
understanding
their
behavior.
In
addition
emphasizing
details
stereocontrolling
elements
individual
reactions,
we
carefully
structured
this
natural
progression
specifics
broader,
class-level
perspective.
Overall,
findings
underscore
critical
role
catalysis
significant
contributions
advancing
synthesis.
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(48), P. 26504 - 26515
Published: Nov. 27, 2023
Conjugated
trienes
are
fascinating
building
blocks
for
the
rapid
construction
of
complex
polycyclic
compounds.
However,
limited
success
has
been
achieved
due
to
challenging
regioselectivity
control.
Herein,
we
report
an
enantio-
and
diastereoselective
process
allowing
regioselectively
control
functionalization
NH-triene-carbamates.
Synthesis
chiral
cis-3,6-dihydro-2H-1,2-oxazines
is
by
a
phosphoric
acid
catalyzed
Nitroso-Diels-Alder
cycloaddition
involving
[(1E,3E,5E)-hexa-1,3,5-trien-1-yl]carbamates.
Moreover,
modular
access
three
different
regioisomers
with
excellent
diastereoselectivities
high
enantioselectivities
obtained
careful
choice
reaction
conditions.
A
computational
study
reveals
that
influenced
steric
demand
substituents
at
6-position
triene,
as
well
noncovalent
interactions
between
two
partners.
Utility
each
regioisomeric
cycloadduct
highlighted
variety
synthetic
transformations.
Organic & Biomolecular Chemistry,
Journal Year:
2022,
Volume and Issue:
20(10), P. 2069 - 2074
Published: Jan. 1, 2022
An
efficient
gold(
i
)-catalyzed
dearomative
cyclization
of
N
-alkynyl
quinazolinone-tethered
C2-substituted
indoles
to
prepare
various
spiroindolenine-3,3′-pyrrolo[2,1-
b
]quinazolinones
in
good
excellent
yields
is
reported.
Advanced Synthesis & Catalysis,
Journal Year:
2022,
Volume and Issue:
364(10), P. 1708 - 1715
Published: April 13, 2022
Abstract
An
enantioselective
chiral
phosphoric
acid
catalyzed
formal
[4+2]
cycloaddition
between
2‐benzothiazolimines
and
N
‐H‐1,3‐dienecarbamates
is
described.
A
divergence
in
reaction
pathways
was
observed
depending
on
the
dienes
employed.
The
performed
with
4‐substituted
produced
benzothiazolopyrimidines
as
major
product
yields
ranging
from
42
to
67%,
single
diastereoisomer
enantioselectivity
93
99%.
same
3‐substituted
dienes,
however,
gave
highly
enantioenriched
1,2,3,4‐tetrahydroquinolines
products
albeit
moderate
diastereoselectivity.
magnified
image
