- Email: [email protected]
Stereochemistry of compounds related to torus. enantiomerism
Tetrahedron Letters,Vol.24,No.31,pp Printed in Great Britain
STEREOCHEMISTRY
OF COMPOUNDS T.H.
Department
3187-3190,1983
Ghan*
of Chemistry,
RELATED
oo40-4039/83 $3.00 + .oo 01983 Pergamon Press Ltd.
TO TORUS.
ENANTIOMERISM
and G.J. Kang,
McGill University, Canada H3A 2K6
Montreal,
Quebec,
Abstract: Optical resohtion of compounds 4 and 9 were achieved. The existence of the enantiomer-lsmis analysed in teriGsof Eke stereochemistryof compounds related to tents. Torus
(1) is related
This
can be illustrated
Just
as planar
useful
cyclic
to consider
permits
topologically
by the punctured polyenes
cyclic
us to look beyond
sense,
ethers
have
meridian.
torus
been
on their
also
Various
surface
(3) which
referred
as having
the different
and concentrate
a uniform
have
hydrocarbons
hydrocarbons crown
to the planar
to as annulenes2,
conformations similar
is a bridged
the torus
annulus.
it may be
structure.
assumed
topological
1
(2) .
annulus
This
by the cyclic
properties.
In this
the torus
structure even though they do not have 3 cyclophanes can be regarded as punctured toruses.
0 0
1
We define separates
a plane
the space
space
above
torus
on the plane,
either defined
above
cavity
and below
as torus
or
to give either
a torus
to the torus When
becomes
the plane,
along
its longitude.
into three
two groups,
parts:
If a group
(2) the group enantiomers
(1) the group
C can dissociate E and E*.
3187
the to a
C is placed
(E, E*) are enantiomeric,
Enantiomerization
two processes.
This plane
the cavity,
A and B, are attached
pro-chira14.
the two arrangements
enantiomers.
of the following
of the torus
the torus
bisects
the plane.
the plane
or below
herein
by either
which
relative
(E can be achieved _ r" E*) C can pass through the
and then
If either
recombine
processes
with
are pro-
3188
optical
hibited,
resolution
of the two enantiomers
is in principle
feasible 5 .
E"
E
C We have the enamine under
recently
synthesized
5 derived
acid-catalysed
clearly
that
cavity plane
the morpholino
of the hydrocarbon of the torus,
enantiomers. O-methyl
Scheme
the conditions able
according
8-
5
to resolve
to scheme
poH
When
4 was reacted
The ester
yield.
distinguishable
by
pentane,
for the existence
gave
copically
mirror
Similar
with
We believe
that
(+)-4,
relationshi_p
in due course.
in essentially
of two diastereomers, chromatography8
acetate
as eluent
(7) and
4-
quantitative
c1 and
B, clearly
on silica
gel column
led to separation with
lithium
of the
aluminum
(acetone) I otherwise
spectros-
compound. Similar reduction of the i320 [a], = + 26" (acetone). The two enantiomers
in their
ORD curves
has been
successful
of compounds
!! chloride
acid
formed
[al, 2o = -30°
resolution
this
the
~
of the a-diastereoisomer with
from the corresponding
the stereochemistry reported
LAH gave
8 was
flash
and ethyl
to the racemic
successful
9, synthesized
the ester
Careful
Reduction
image
via
1.
g@_z_CH
as a mixture
acetonitrile
identical
diastereomer
with
the phenol(-)-4,
of torus
the two enantiomers
L (R)-(-)-0-methylmandelic
in THF,
8 existed -1 H nmr'.
two diastereomers. hydride
of 6
&le
z
dimethylaminopyridine
showed
satisfying
29
1
using
4 by condensation
group is too large to be accommodated inside the 11 . It must be placed either above or below the
in fact been
esters
..,,.X.,.:
compound
torus
thus
We have
mandelate
the m-cyclophane
from cyclododecanone (scheme 1) and the silyl compound 6 conditions . Examination of molecular model of 4 shows
enamine resolution
related
(Figure
achieved
with
derived opens
to torus.
1).
the phenolic
compound from cyclopentadecanone 10 .
the door
Further
to the study
results
will
be
of
3189
[+I uo*
+24 +20 +l 6 +I2 *a +4 c -4 -1 -1: -1t -21 -2i
250 Figure 1:
300
35Onm
Optical Rotatory Dispersion Curves of Compounds j, and 2. The ORD curve of +9 is enantiomeric to the -isomer.
3190
Acknowledgement:
The authors thank NSERC of Canada and FCAC of Quebec for
financial support of this research.
GJK thanks the government of the People's
Republic of China for a,scholarship. References 1.
H.B. Griffiths, Surfaces, Cambridge University Press, Cambridge, 2nd ed.,
2.
F. Sondheimer and R. Wolovsky, J. Amer. Chem. Sot., 84, 260 (1962).
1981. 3.
See B.H. Smith, "Bridged Aromatic Compounds", Academic Press, New York, 1964.
4.
K.R. Hanson, J. Amer. Chem. Sot., E,
5.
2731 (1966).
The exception is when A,B,C lie on a plane perpendicular to and bisecting the torus.
The existence of this kind of enantiomerism was recognized, but
optical resolution was unsuccessful.
See G. Schill, Chem. Ber., 99, 2689
(19661, also G. Schill, Catenanes, Rotaxanes and Knots, Academic Press, 1971, New York, p. 60. 6.
Experimental conditions: to a mixture of 5 _ (2.57 g, 10 mmol) and 6 (1.2 g, 5 mmol)' trifluoroacetic acid (1.14 g, 10 mmol) was added drop by drop at O°C with stirring.
The mixture was warmed up to room temperature and
stirred for 10 minutes and then heated to 80' for 24 hrs. reaction mixture, 300 ml ether was added.
To the cooled
The ether solution was washed
with aqueous acid (1.5N HCl), dried (MgS04), and evaporated to give 2.45 g of brown oil.
Flash chromatography8 on silica gel, eluted with petroleum
ether/ethyl acetate gave 0.81 g 2, (51% yield).
M-p. 174-177 'H nmr (CDC13):
6.40 (s,lH), 4.66 (s,lH), 3.70-3.86 (m,4H), 3.16-3.33
(m,4H), 2.54-3.10 (m,4H), 2.18 (s,3H), 0.68-1.5 (m,12H), 0.2-0.4 (m,2H); IR(KBr): 3290, 1590, 1110 cm-'; MS: m/z = 317 (91%), 260 (37%), 249 (100%). 7.
T.H. Chan and G.J. Kang, Tetrahedron Letters, 23, 3011 (1982).
8.
W.C. Still, M. Khan and A. Mitra, J. Org. Chem., 43, 2923 (1978).
9.
1H nmr (cDc~~): cc-isomer, 7.32-7.54 (m,5H), 6.52(s,lH), 4.94(s,lH), 3.68-3.73 (m,4H), 3.50 (S,3H), 3.14-3.18 (m,4H), 3.0-2.4 (m,4H), 2.18 (s,3H), 1.9-O-l (m,14H); B-isomer, 7.32-7.54 (m,5H), 6.61 (s,lH), 4.94 (s,lH), 3.66-3.71
10.
11.
(m,4H), 3.46 (s,3H), 3.14-3.16 (m,4H), 3.0-2.4 (m,4H), 2.18 (s,3H), 1.9-0.1 (m,14H). 1 Compound 9: m.p. 201-204°; H nmr (CDC13), 6.46 (s,lH), 4.44(s,lH), 3.713.82 (m,4H), 2.40-3.5 (m,8H), 2.21 (s,3H), 1.8-O-8 (m,20H); IR (KBr), 3300, -1 1585, 1100 cm ; MS, m/z = 359 (100%). For (+)-isomer, [a], 20 = + 11' (THF); 2o = - 170 (THF). (-)-isomer, [al D X-ray structure determination of a m-cyclophane has recently been reported. F. Effenberger, K-H. Sch6nwalder and J.J. Stezowski, Angew. Chem. Internat. Ed., 21, 871 (1982). (Received in USA 2 May 1983)
STEREOCHEMISTRY
OF COMPOUNDS T.H.
Department
3187-3190,1983
Ghan*
of Chemistry,
RELATED
oo40-4039/83 $3.00 + .oo 01983 Pergamon Press Ltd.
TO TORUS.
ENANTIOMERISM
and G.J. Kang,
McGill University, Canada H3A 2K6
Montreal,
Quebec,
Abstract: Optical resohtion of compounds 4 and 9 were achieved. The existence of the enantiomer-lsmis analysed in teriGsof Eke stereochemistryof compounds related to tents. Torus
(1) is related
This
can be illustrated
Just
as planar
useful
cyclic
to consider
permits
topologically
by the punctured polyenes
cyclic
us to look beyond
sense,
ethers
have
meridian.
torus
been
on their
also
Various
surface
(3) which
referred
as having
the different
and concentrate
a uniform
have
hydrocarbons
hydrocarbons crown
to the planar
to as annulenes2,
conformations similar
is a bridged
the torus
annulus.
it may be
structure.
assumed
topological
1
(2) .
annulus
This
by the cyclic
properties.
In this
the torus
structure even though they do not have 3 cyclophanes can be regarded as punctured toruses.
0 0
1
We define separates
a plane
the space
space
above
torus
on the plane,
either defined
above
cavity
and below
as torus
or
to give either
a torus
to the torus When
becomes
the plane,
along
its longitude.
into three
two groups,
parts:
If a group
(2) the group enantiomers
(1) the group
C can dissociate E and E*.
3187
the to a
C is placed
(E, E*) are enantiomeric,
Enantiomerization
two processes.
This plane
the cavity,
A and B, are attached
pro-chira14.
the two arrangements
enantiomers.
of the following
of the torus
the torus
bisects
the plane.
the plane
or below
herein
by either
which
relative
(E can be achieved _ r" E*) C can pass through the
and then
If either
recombine
processes
with
are pro-
3188
optical
hibited,
resolution
of the two enantiomers
is in principle
feasible 5 .
E"
E
C We have the enamine under
recently
synthesized
5 derived
acid-catalysed
clearly
that
cavity plane
the morpholino
of the hydrocarbon of the torus,
enantiomers. O-methyl
Scheme
the conditions able
according
8-
5
to resolve
to scheme
poH
When
4 was reacted
The ester
yield.
distinguishable
by
pentane,
for the existence
gave
copically
mirror
Similar
with
We believe
that
(+)-4,
relationshi_p
in due course.
in essentially
of two diastereomers, chromatography8
acetate
as eluent
(7) and
4-
quantitative
c1 and
B, clearly
on silica
gel column
led to separation with
lithium
of the
aluminum
(acetone) I otherwise
spectros-
compound. Similar reduction of the i320 [a], = + 26" (acetone). The two enantiomers
in their
ORD curves
has been
successful
of compounds
!! chloride
acid
formed
[al, 2o = -30°
resolution
this
the
~
of the a-diastereoisomer with
from the corresponding
the stereochemistry reported
LAH gave
8 was
flash
and ethyl
to the racemic
successful
9, synthesized
the ester
Careful
Reduction
image
via
1.
g@_z_CH
as a mixture
acetonitrile
identical
diastereomer
with
the phenol(-)-4,
of torus
the two enantiomers
L (R)-(-)-0-methylmandelic
in THF,
8 existed -1 H nmr'.
two diastereomers. hydride
of 6
&le
z
dimethylaminopyridine
showed
satisfying
29
1
using
4 by condensation
group is too large to be accommodated inside the 11 . It must be placed either above or below the
in fact been
esters
..,,.X.,.:
compound
torus
thus
We have
mandelate
the m-cyclophane
from cyclododecanone (scheme 1) and the silyl compound 6 conditions . Examination of molecular model of 4 shows
enamine resolution
related
(Figure
achieved
with
derived opens
to torus.
1).
the phenolic
compound from cyclopentadecanone 10 .
the door
Further
to the study
results
will
be
of
3189
[+I uo*
+24 +20 +l 6 +I2 *a +4 c -4 -1 -1: -1t -21 -2i
250 Figure 1:
300
35Onm
Optical Rotatory Dispersion Curves of Compounds j, and 2. The ORD curve of +9 is enantiomeric to the -isomer.
3190
Acknowledgement:
The authors thank NSERC of Canada and FCAC of Quebec for
financial support of this research.
GJK thanks the government of the People's
Republic of China for a,scholarship. References 1.
H.B. Griffiths, Surfaces, Cambridge University Press, Cambridge, 2nd ed.,
2.
F. Sondheimer and R. Wolovsky, J. Amer. Chem. Sot., 84, 260 (1962).
1981. 3.
See B.H. Smith, "Bridged Aromatic Compounds", Academic Press, New York, 1964.
4.
K.R. Hanson, J. Amer. Chem. Sot., E,
5.
2731 (1966).
The exception is when A,B,C lie on a plane perpendicular to and bisecting the torus.
The existence of this kind of enantiomerism was recognized, but
optical resolution was unsuccessful.
See G. Schill, Chem. Ber., 99, 2689
(19661, also G. Schill, Catenanes, Rotaxanes and Knots, Academic Press, 1971, New York, p. 60. 6.
Experimental conditions: to a mixture of 5 _ (2.57 g, 10 mmol) and 6 (1.2 g, 5 mmol)' trifluoroacetic acid (1.14 g, 10 mmol) was added drop by drop at O°C with stirring.
The mixture was warmed up to room temperature and
stirred for 10 minutes and then heated to 80' for 24 hrs. reaction mixture, 300 ml ether was added.
To the cooled
The ether solution was washed
with aqueous acid (1.5N HCl), dried (MgS04), and evaporated to give 2.45 g of brown oil.
Flash chromatography8 on silica gel, eluted with petroleum
ether/ethyl acetate gave 0.81 g 2, (51% yield).
M-p. 174-177 'H nmr (CDC13):
6.40 (s,lH), 4.66 (s,lH), 3.70-3.86 (m,4H), 3.16-3.33
(m,4H), 2.54-3.10 (m,4H), 2.18 (s,3H), 0.68-1.5 (m,12H), 0.2-0.4 (m,2H); IR(KBr): 3290, 1590, 1110 cm-'; MS: m/z = 317 (91%), 260 (37%), 249 (100%). 7.
T.H. Chan and G.J. Kang, Tetrahedron Letters, 23, 3011 (1982).
8.
W.C. Still, M. Khan and A. Mitra, J. Org. Chem., 43, 2923 (1978).
9.
1H nmr (cDc~~): cc-isomer, 7.32-7.54 (m,5H), 6.52(s,lH), 4.94(s,lH), 3.68-3.73 (m,4H), 3.50 (S,3H), 3.14-3.18 (m,4H), 3.0-2.4 (m,4H), 2.18 (s,3H), 1.9-O-l (m,14H); B-isomer, 7.32-7.54 (m,5H), 6.61 (s,lH), 4.94 (s,lH), 3.66-3.71
10.
11.
(m,4H), 3.46 (s,3H), 3.14-3.16 (m,4H), 3.0-2.4 (m,4H), 2.18 (s,3H), 1.9-0.1 (m,14H). 1 Compound 9: m.p. 201-204°; H nmr (CDC13), 6.46 (s,lH), 4.44(s,lH), 3.713.82 (m,4H), 2.40-3.5 (m,8H), 2.21 (s,3H), 1.8-O-8 (m,20H); IR (KBr), 3300, -1 1585, 1100 cm ; MS, m/z = 359 (100%). For (+)-isomer, [a], 20 = + 11' (THF); 2o = - 170 (THF). (-)-isomer, [al D X-ray structure determination of a m-cyclophane has recently been reported. F. Effenberger, K-H. Sch6nwalder and J.J. Stezowski, Angew. Chem. Internat. Ed., 21, 871 (1982). (Received in USA 2 May 1983)