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Zeolite-catalyzed epoxidation of allylic alcohols
~etrahcdron Lmerr, Vol. 33. No. 22, pp. 3205-X206,1992 Printrd in Grear Britain
Zeolite-Catalyzed
Epoxidation
R. Antomoletti,
F. Ronadies,
Of Allylic Alcohols
L. Locati, A. Scettri*
Centro CNR per lo Studio della Chimica delle Sostanze Organiche
4A molecular stereoselective
Abstract:
sieves have shown to be efficient epoxidation of allylic alcohols.
In these last years the ever increasing has allowed sieves
Naturali,
c/o Dipartimento
di Chimica,
“La Sapienza”, P.le A Mom 5, 00185 Roma, Italy
Universith
the achievement
proved
by protecting
medium.
3
requirement
in organic
role in the catalytic
the Ti catalyst
As known, in the typical the essential
use of zeolites as selective
of several applications
to play a fundamental
alcohols
Sharpless
catalysts
from
traces
epoxidation
for the formation
asymmetric
of epoxyalcohols,
molecular
sieves can be conveniently
employed
procedure
for the epoxidation
(t-BuOUH)
of allylic
in the reaction
metal catalysis any previous
represents takes place
metal doping,
in a mild and simplified
of allylic alcohols.
materials
in the presence
Table, are smoothly
For ex. molecular
water
catalysts
and
and absorbents
that, furthermore,
We have found that, without as selective
regio-
epoxidation
of adventitious
with high regio- and stereoselectivity.
In fact, starting
catalysts
synthesis.‘2
the transition
for
1, submitted
of activated
converted
to the action of an excess of t-butyl hydroperoxide
4A molecular
into the corresponding
t-BuOOH,
sieves,
under
epoxyalcohols
the conditions
2 in satisfactory
given in way,
CHC13
molecular sieves 2
1 Usually however, process observed
the
conversion
comparable at higher
yields
1 +
under conditions
starting
materials
evidence
of formation
to proceed
can be obtained
temperatures
be noted that epoxidation
2 proves
(entries
involving
very
in reduced
slowly
reaction
at room times
B and l$,, while no significant
an increased
t-BuOOWsubstrate
of isomer+
additional epoxides
C-C
double
bonds
has been detected.
3205
carrying
improvement
out the has been
ratio (entry c). It has to
occurs with high regio- and stereoselectivity:
presenting
temperature:
(entries
in fact, in the case of a-.-$), no significant
Sting
materials
lMdUCt!i
Temp.
t-BuOOH/eq
2,3-epoxygeraniol ‘L
Time/h
Yield%h)
1.4
r.t.
144
67
1.4
6093
48
67
2.0
r-t.
144
60
1.4
r.t.
96
50
LO”
1.4
45?z
72
73
JQ?+-Xf”
1.4
r.t.
72
2.0
4sc
96
63
2.0
reflux
72
W)
GUWlid 1‘
‘1 2,3-epoxyfarnesol
Famesol
-H
\ $
H
a) Epoxidmions have been performed on 5_3 mm01 scale and carried u) about 80% conversion. b)All the yields rqfer to isolated, chromatographically pure cornpounds. AI1 the assigned structures have been confirmed by II?, ‘H NMR and MS datu or by comparison with authentic samples, C, Biastereoisomeric ratios have been determined by IH NMR (300 MH.z).~~T~ %‘O:IO threo/erythro Furthermore, predominant
epoxidation way (entries
of secondary
allylic
e) 97:3 cisltram (by GLC on acetute). alcohols
Although this procedure involves the employment results
are reminiscent
investigations
affords
one
stereoisomer
in
fand h).
of transition
metal catalyzed
of non-exchanged epoxidation:
zeolites, the first therefore,
further
on the mechanistic aspects are in progress.
III a typical experimental procedure, a mixture of allylic alcohol (5.3 mmol), dissolved in dry CHCl3 (26.5 ml), t-butyl hydroperoxide (appropriate volume of 3M toluene solution) (see Table), activate& 4A molecular sieves (0.5-0.7 g), is stirred under argon. After the completion of the reaction (monitored by lH NMR) dimethyl sulfide (0,5 ml) is added and the solution is directly
poured
hexane/diethyl
into the top of a silica
gel cromatographic
column.
Elution
with n-
ether mixtures affords pure epoxyalcohols.
REFERENCES 1.
Holderich, W.; Hesse, M,; NBumann, F,Angeu~. Chemie
2.
Van Bekkum, H.;
Sharpless, K.B. J. Org. Chem,
Trav.
1988, 100,232.
Chim. PUNS-BUS 19f@, 108,283.
3.
Hanson,
4.
Rossiter, B.E.; Verhoeven, T.R.;
5.
Mihelich, E.B. Tetrahedron Lett., 197!$4729. Itoh, T.; Jit,sukawa, K.; Kaneda, K,; Teranishi, S. J. Am.. Chem.
6.
R.&l,;
Kouwenhoven, H.W. Reck
(P.cceivedin UK 6 February 1992)
1987? 51,192X
Sharpless, K.B. Tetrahedron
Lett.
1979,4733. SOC.
1979, 101, 159.
Zeolite-Catalyzed
Epoxidation
R. Antomoletti,
F. Ronadies,
Of Allylic Alcohols
L. Locati, A. Scettri*
Centro CNR per lo Studio della Chimica delle Sostanze Organiche
4A molecular stereoselective
Abstract:
sieves have shown to be efficient epoxidation of allylic alcohols.
In these last years the ever increasing has allowed sieves
Naturali,
c/o Dipartimento
di Chimica,
“La Sapienza”, P.le A Mom 5, 00185 Roma, Italy
Universith
the achievement
proved
by protecting
medium.
3
requirement
in organic
role in the catalytic
the Ti catalyst
As known, in the typical the essential
use of zeolites as selective
of several applications
to play a fundamental
alcohols
Sharpless
catalysts
from
traces
epoxidation
for the formation
asymmetric
of epoxyalcohols,
molecular
sieves can be conveniently
employed
procedure
for the epoxidation
(t-BuOUH)
of allylic
in the reaction
metal catalysis any previous
represents takes place
metal doping,
in a mild and simplified
of allylic alcohols.
materials
in the presence
Table, are smoothly
For ex. molecular
water
catalysts
and
and absorbents
that, furthermore,
We have found that, without as selective
regio-
epoxidation
of adventitious
with high regio- and stereoselectivity.
In fact, starting
catalysts
synthesis.‘2
the transition
for
1, submitted
of activated
converted
to the action of an excess of t-butyl hydroperoxide
4A molecular
into the corresponding
t-BuOOH,
sieves,
under
epoxyalcohols
the conditions
2 in satisfactory
given in way,
CHC13
molecular sieves 2
1 Usually however, process observed
the
conversion
comparable at higher
yields
1 +
under conditions
starting
materials
evidence
of formation
to proceed
can be obtained
temperatures
be noted that epoxidation
2 proves
(entries
involving
very
in reduced
slowly
reaction
at room times
B and l$,, while no significant
an increased
t-BuOOWsubstrate
of isomer+
additional epoxides
C-C
double
bonds
has been detected.
3205
carrying
improvement
out the has been
ratio (entry c). It has to
occurs with high regio- and stereoselectivity:
presenting
temperature:
(entries
in fact, in the case of a-.-$), no significant
Sting
materials
lMdUCt!i
Temp.
t-BuOOH/eq
2,3-epoxygeraniol ‘L
Time/h
Yield%h)
1.4
r.t.
144
67
1.4
6093
48
67
2.0
r-t.
144
60
1.4
r.t.
96
50
LO”
1.4
45?z
72
73
JQ?+-Xf”
1.4
r.t.
72
2.0
4sc
96
63
2.0
reflux
72
W)
GUWlid 1‘
‘1 2,3-epoxyfarnesol
Famesol
-H
\ $
H
a) Epoxidmions have been performed on 5_3 mm01 scale and carried u) about 80% conversion. b)All the yields rqfer to isolated, chromatographically pure cornpounds. AI1 the assigned structures have been confirmed by II?, ‘H NMR and MS datu or by comparison with authentic samples, C, Biastereoisomeric ratios have been determined by IH NMR (300 MH.z).~~T~ %‘O:IO threo/erythro Furthermore, predominant
epoxidation way (entries
of secondary
allylic
e) 97:3 cisltram (by GLC on acetute). alcohols
Although this procedure involves the employment results
are reminiscent
investigations
affords
one
stereoisomer
in
fand h).
of transition
metal catalyzed
of non-exchanged epoxidation:
zeolites, the first therefore,
further
on the mechanistic aspects are in progress.
III a typical experimental procedure, a mixture of allylic alcohol (5.3 mmol), dissolved in dry CHCl3 (26.5 ml), t-butyl hydroperoxide (appropriate volume of 3M toluene solution) (see Table), activate& 4A molecular sieves (0.5-0.7 g), is stirred under argon. After the completion of the reaction (monitored by lH NMR) dimethyl sulfide (0,5 ml) is added and the solution is directly
poured
hexane/diethyl
into the top of a silica
gel cromatographic
column.
Elution
with n-
ether mixtures affords pure epoxyalcohols.
REFERENCES 1.
Holderich, W.; Hesse, M,; NBumann, F,Angeu~. Chemie
2.
Van Bekkum, H.;
Sharpless, K.B. J. Org. Chem,
Trav.
1988, 100,232.
Chim. PUNS-BUS 19f@, 108,283.
3.
Hanson,
4.
Rossiter, B.E.; Verhoeven, T.R.;
5.
Mihelich, E.B. Tetrahedron Lett., 197!$4729. Itoh, T.; Jit,sukawa, K.; Kaneda, K,; Teranishi, S. J. Am.. Chem.
6.
R.&l,;
Kouwenhoven, H.W. Reck
(P.cceivedin UK 6 February 1992)
1987? 51,192X
Sharpless, K.B. Tetrahedron
Lett.
1979,4733. SOC.
1979, 101, 159.