Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(2), P. 508 - 513
Published: Jan. 5, 2024
The
enantioselective
allylic
alkylation
of
nitro
ketene
aminals
with
racemic
alcohols
was
realized
by
iridium/acid
dual
catalysis.
An
allyl
group
installed
on
the
α-position
in
a
branched-selective
manner
high
efficiency
excellent
enantioselectivities
(93–99%
ee).
protocol
applied
to
late-stage
modification
neonicotinoid
insecticides,
which
directly
furnished
novel
analogue
good
insecticidal
activity
against
Aphis
craccivora
(LC50
=
6.40
mg/L).
On
basis
control
experiment,
an
aza-ene-type
reaction
mechanism
proposed.
Organic Letters,
Journal Year:
2023,
Volume and Issue:
25(2), P. 325 - 330
Published: Jan. 6, 2023
An
asymmetric
cascade
allylation/spiroketalization
reaction
between
2-(1-hydroxyallyl)phenols
and
5-methyleneoxazolines
is
accomplished
by
using
a
chiral
Ir(I)
catalyst
derived
from
commercially
available
iridium
precursor
the
Carreira
ligand.
This
protocol
furnishes
class
of
structurally
novel
unique
oxazoline-spiroketals
in
up
to
86%
yield,
>99%
ee
>20:1
dr.
Moreover,
control
experiments
reveal
that
4,4-disubstitution
on
necessary
avoid
aromatization
for
spiroketalization
occur.
On
basis
this,
plausible
mechanism
illustrated.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(6), P. 2460 - 2467
Published: Feb. 3, 2022
A
novel
protocol
is
established
for
the
long-standing
challenge
of
stereoselective
geminal
bisglycosylations
saccharides.
The
merger
PPh3
as
a
traceless
glycosidic
leaving
group
and
1,2-boronate
migration
enables
simultaneous
introduction
C–C
C–B
bonds
at
anomeric
stereogenic
center
furanoses
pyranoses.
power
this
method
showcased
by
set
site-selective
modifications
glycosylation
products
construction
bioactive
conjugates
skeletons.
scarce
metal-free
1,1-difunctionalization
process
alkenes
also
concomitantly
demonstrated.
Journal of the American Chemical Society,
Journal Year:
2022,
Volume and Issue:
144(35), P. 16118 - 16130
Published: Aug. 29, 2022
Iridium(phosphoramidite)
complexes
catalyze
an
enantio-
and
diastereoselective
three-component
coupling
reaction
of
alkenyl
boronic
esters,
organolithium
reagents,
secondary
allylic
carbonates.
The
proceeds
through
allylation-induced
1,2-metalate
shift
the
boronate
to
form
non-adjacent
stereocenters.
Mechanistic
investigations
outline
overall
catalytic
cycle
reveal
trends
in
reactivity
selectivity.
Analysis
relative
stereochemistry
products
derived
from
a
variety
1,1-disubtituted
boronates
provides
insight
into
transition
state
addition
indicates
concerted
pathway.
Kinetic
analysis
revealed
kinetic
order
dependence
boronate,
catalyst,
both
slow-
fast-reacting
enantiomer
carbonate
as
well
turnover-limiting
step
reaction.
Determination
nucleophile-specific
parameters
N
sN
for
enabled
comparison
other
classes
nucleophiles.
DFT
calculations
indicate
cationic
Ir(π-allyl)
intermediate
occur
mechanism.
stereoselectivity
is
determined
by
ligand–substrate
steric
repulsions
dispersion
interactions
syn
state.
Hammett
studies
supported
computational
results
with
regard
electronic
observed
aryl-derived
aryl
Organic Letters,
Journal Year:
2024,
Volume and Issue:
26(2), P. 508 - 513
Published: Jan. 5, 2024
The
enantioselective
allylic
alkylation
of
nitro
ketene
aminals
with
racemic
alcohols
was
realized
by
iridium/acid
dual
catalysis.
An
allyl
group
installed
on
the
α-position
in
a
branched-selective
manner
high
efficiency
excellent
enantioselectivities
(93–99%
ee).
protocol
applied
to
late-stage
modification
neonicotinoid
insecticides,
which
directly
furnished
novel
analogue
good
insecticidal
activity
against
Aphis
craccivora
(LC50
=
6.40
mg/L).
On
basis
control
experiment,
an
aza-ene-type
reaction
mechanism
proposed.
