Diastereoselective (8+3)‐Cycloadditions of Donor‐Acceptor Cyclopropanes with Tropothione
European Journal of Organic Chemistry,
Journal Year:
2023,
Volume and Issue:
27(6)
Published: Dec. 27, 2023
Abstract
Reactions
of
dimethyl
2‐arylcyclopropane‐1,1‐dicarboxylates,
used
as
representatives
D‐A
cyclopropanes,
with
tropothione
were
carried
out
in
the
presence
scandium
triflate
a
catalyst,
under
mild
conditions
(CH
2
Cl
solution,
rt).
The
anticipated
(8+3)‐cycloaddition
products,
cycloheptatriene
fused
thiopyrans,
obtained
good
to
excellent
yields.
Cycloadditions
occurred
complete
diastereoselectivity
and
all
cases
single
diastereomers
formed.
Structures
isolated
cycloadducts
established
based
on
spectroscopic
data
two
they
unambiguously
confirmed
by
crystal
X‐ray
diffraction
analysis.
In
contrast
an
analogous
reported
for
parent
tropone,
which
was
performed
Ni(ClO
4
)
,
no
1,3‐
H
shift
leading
products
possessing
CH
moiety
located
within
seven‐membered
ring
observed.
Language: Английский
Expedient sulfurization with elemental sulfur and an unexpected conversion of 2,3-diarylcyclopropenethiones using tetrabutylammonium fluoride (TBAF) as a source of the fluoride anion
Journal of Fluorine Chemistry,
Journal Year:
2023,
Volume and Issue:
270, P. 110170 - 110170
Published: July 31, 2023
Language: Английский
(3+2)-Cycloadditions of Levoglucosenone (LGO) with Fluorinated Nitrile Imines Derived from Trifluoroacetonitrile: An Experimental and Computational Study
Molecules,
Journal Year:
2023,
Volume and Issue:
28(21), P. 7348 - 7348
Published: Oct. 30, 2023
The
in
situ-generated
N-aryl
nitrile
imines
derived
from
trifluoroacetonitrile
smoothly
undergo
(3+2)-cycloadditions
onto
the
enone
fragment
of
levoglucosenone
molecule,
yielding
corresponding,
five-membered
cycloadducts.
In
contrast
to
‘classic’
C(Ph),N(Ph)
imine,
reactions
with
fluorinated
C(CF3),N(Ar)
analogues
lead
stable
pyrazolines
a
chemo-
and
stereoselective
manner.
Based
on
result
X-ray
single
crystal
diffraction
analysis,
their
structures
were
established
as
exo-cycloadducts
location
N-Ar
terminus
1,3-dipole
at
α-position
moiety.
DFT
computation
demonstrated
that
observed
reaction
pathway
results
strong
dominance
kinetic
control
over
thermodynamic
control.
Language: Английский