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N-iodosuccinimide mediated oxidative cyclization of mono-t-butyldimethylsilylated diols
Tetrahedron Letters,Vo1.30,No.36,pp Printed in Great Britain
0040-4039/89 $3.00 Perqamon Press plc
4791-4794,1989
N-IODOSUCCINIMIDE MEDIATED OXIDATIVE OF MONO-1.BUTYLDIMETHYLSILYLATED
+ .OO
CYCLIZATION DIOLS
Chriss E. McDonald,*a Thomas R. Beebe,‘b Mark Beard,b Doug McMil1en.b Daniel Selskib aLycoming
College,
Williamsport,
bBerea College,
PA
Berea, KY
17701
40404
Summarv; The oxidation of mono-t-butyldimethylsilylated diols is described. The t-butytdimethylsilyl moiety is useful for controlling both the direction of cyclization and the size of ring being formed. We have previously
shown that
light leads to the formation
treatment
of 1-pentanol
of 2-methyltetrahydrofuran.
1 Herein we describe
NE, Ho-
methodology
to the regioselective
were converted McDougal.2 using
Chaudary’s
A plausible is homolytically (6-->7,
counterparts
4-dimethylaminopyridine mechanism cleaved
Barton-type
butyldimethylsilyl
to produce
reaction), acetal
catalyzed
an alkoxy
iodination.
acetals.
silylated
of
alkoxides
benzene,
NaHCO,,
c:
1. 5
ring closure
The initially formed Intramolecular
furnishes
0
V
35%
h-d
OTBS
4 -HI
N-l
1
0
HOFOTBS
0
I
N-H
6
c 0
5 hd
5
-I’
_
o/.,,/,,OTBS
*
by
group
6
4791
;
hypoiodite
I,5 hydrogen
the observed
1
3
l_O+.../,+OTBS
dials
as described hydroxyl
4.
&-W-VOTBS
this
Symmetrical
at the primary
radical and an iodine radical.
and nucleophilic
NIS,
of
procedure.3p4
is shown in Scheme
Scheme
0
an extension
diols via their monosodium were selectively
for this transformation
in the presence
hd
of mono-t-butyldimethylsilylated
to their mono-t-butyldimethylsilylated Their unsymmetrical
(NE)
benzene
reflux,
cyclization
with N-iodosuccinimide
HOFoTBS 7
t-
5
shift
4792
The results of our cyclitation worthy of note. corresponding constitutes
studies
These reactions simple
aliphatic
a regioselective
diol gets oxidized.
are shown in Table 1 .6 Several
take place under milder conditions alcohols.
oxidation
(entries 4 and
6).
The silylationloxidation
procedure
aspects of this oxidation
than are required sequence
in which the less substituted
It is thought that Table
are
for the
for prim-set
diols
(and protected)
end of the
the poor yield of the ketal shown in entry 5
1
l
Alcohol
Entry 1
Eq NIS
f&x+@bOTBS
Time (h)
1.7
2
1.5
Product(s)
V
6
Yield a 72%
0
OTBS
12
84% OTBS
3
1.5
6
63% + OTSS
6% OTBS 4
5
6
HO~OTBS
HO
&OTBS
OTBS
2.3
8
1.5
12
~OTBS
11%
2-6
VBS
7
HO-OTBS
87%
2.8
34
12%
60%
7%
aAll yields are isolated
except for entry 7 which were obtained
by gas chromatography.
4793
is due to the presence I-5
hydrogen
shM7
upon irradiation
of significant It is interesting
in the presence
1,3-syn
diaxial
moiety functions
Entry 6 shows that hydrogen incipient
carbon
illustrates abstraction transition
radical
the ability
abstraction
to the t-butyldimethylsiloxy
of the t-bulyldimelhylsiloxy
via a seven-membered state.
The stabilization
be viewed as an interaction singly occupied
carbon
Diastereomeric confirmation
p orbital.’
mixtures
to produce
Lewis acid mediated
group
It appears
cyclic transition
group
group
imparts
nonbonding
direct
fhe intramolecular six-membered
to an adjacent
carbon
Entry 7 hydrogen cyclic radical can
molecular orbital of the oxygen and the
g
of acetals were produced
in entries 2, 4, and 6. appropriate.
was deemed
the corresponding processes
known lactones (Scheme 2). of t-butyldimethylsilylated
In these cases further
These products
CrO,, &SO+, H,O
0
-78°C
-,
RT, 77%
OTBS
CrO,, -78“C
H,50,, --+
RT,
H,O
were thus subjected
to
In the future we plan to examine
acetals.
Scheme 2
cc
of the mechanism.
than an alkyl group.312
assignments
substitution
that the t-
shift portion
stale rather than the normal
a t-butyldimethylsiloxy
analogue
much more readily when the
to selectively
between the doubly occupied
of the structural
Jones oxidation
radical ocWs
state for the
only the aldehyde
t-butyldimethylsilyl
group for the hydrogen
by the alkoxy
transition
alcohol furnishes
The corresponding
upon reaction with NIS.
as a directing
is adjacent
in the chair-like
to note that o-methylbenzyl
of NIS in benzene. 1
(entry 3) affords the acetal as the major product butyldimethylsiloxy
interactions
=G
0 0
4794
lyrical
EQerimeotal
Procedure
To a solution
of cis-I -O-t-butyldimethylsilyl-l,2-cyclohexanedimethanol
entry 2) in benzene heterogenous
reaction
mixture
was irradiated
Water (5 mL) and Na2S203.H20 species.
The resultant
combined
organic extracts
reduced pressure. ethyl acetate colorless acetal
0.31
mmol,
(0.60 mmol).
was extracted
any NIS or hypoiodite
with a 50% ether in hexane
were then washed with water (5 ml),
The crude residue was chromatographed
mixture
The
lamp.
containing
(4 X 5 mL).
and the solvent was removed
The under
on a 35 X 1 cm column of silica gel with 1%
to afford 67 mg (0.26 mmol, 84% yield) of the corresponding
cyclic acetal as a
: 1 mixture of diastereomers at the acetal center as determined by integration of the 1H NMR signals). IR (neat) 2940. 2880, 1470, 1460, 1320, cm-l; 1 H NMR (60 MHz,
oil (1.6
5.4 (d, J = 2 Hz. IH.
2.1 (m, ZH), (MH+,
mg,
at 35OC for 12 h with a G.E. 150 W, 130 V tungsten
(0.5 g) were then added to destroy
mixture
in hexane
proton
CDCl3)
(80
(1.6 ml) was added 105 mg NIS (0.47 mmol) and 51 mg NaHC03
1.9-1.2
loo),
major diastereomer),
(m, 8H),
199
(8),
146
0.1 (s, H-l);
0.9 (s, 9H), (5),
125
5.2 (br s, lH,
minor diastereomer),
MS (Cl),
m/z
(relative
3.9 (m, 2H),
intensity)
257
(57).
Acknowledgements We are grateful to the Jessie Ball DuPont Religious, Chemistry
Fund of Berea College
to Steven Stout of American References 1.
and
Fund and the Julian Capps
a summer research grant for C.E.M.
for performing
Webb, M.;
R.; Bogardus,
Yates, S.
. We are also grateful
the mass spectral analyses.
C.; Champney,
2.
McDougal,
P.; Rico, J.; Oh, Y.: Condon,
Chaudary,
S.; Hernandez,
4.
All of the diols were commercially aluminum
hydride
Meystere,
C.; Heusler,
B.; Hii, P.; Reinking,
J. Org. Chem. 1983,
3.
5.
and Educational
notes
Beebe, T.; Adkins, W.;
for providing
Cyanamid
Charitable,
0.
reduction
J.;
Weatherford,
B. J. Org. Chem. 1986, 51, 3388.
Tetrahedron available
Leff., 1979, 20, 99. except
of gamma-octanoic
K.: Kalvoda,
P.; Shadday,
48, 3126.
for 1,5-octanediol
which was obtained
by
lithium
lactone.
J.; Wieland,
P.; Anner,
G.; Wettstein,
A. fxperentia,
1961,
17,
475. 6.
All starting materials and products were characterized
by IR,
1H NMR,
elemental
analysis
and/or
GUMS. 7.
The necessity previously,
8.
For an example van der Gen,
9.
Bernardi, 98,
of low-energy
see:
Heusler,
chair conformations
K.; Kalvoda,
of oxygen-directed, A. Tetrahedron
J. Angew.
regioselective
Lett. 1976,
F.; Epiotis, N.; Cherry,
for efficient
1,5hydrogen
shifts has been noted
Chem. Int. Ed. Engl. 1964, 3, 525. radical chlorination
see:
Kruse, C.; Broekhof,
W.; Schlegel, H.; Whangbo, M.; Wolfe, S. J. Am. Chem. Sot. 1976,
469.
IO. Viehe, H.; Merenyi, R.; Stella, L.; Janousek, 2. Angew Chem Int M fngl. (Received
in USA
19 May
N.;
17. 1725.
1989)
1979,
18, 917.
0040-4039/89 $3.00 Perqamon Press plc
4791-4794,1989
N-IODOSUCCINIMIDE MEDIATED OXIDATIVE OF MONO-1.BUTYLDIMETHYLSILYLATED
+ .OO
CYCLIZATION DIOLS
Chriss E. McDonald,*a Thomas R. Beebe,‘b Mark Beard,b Doug McMil1en.b Daniel Selskib aLycoming
College,
Williamsport,
bBerea College,
PA
Berea, KY
17701
40404
Summarv; The oxidation of mono-t-butyldimethylsilylated diols is described. The t-butytdimethylsilyl moiety is useful for controlling both the direction of cyclization and the size of ring being formed. We have previously
shown that
light leads to the formation
treatment
of 1-pentanol
of 2-methyltetrahydrofuran.
1 Herein we describe
NE, Ho-
methodology
to the regioselective
were converted McDougal.2 using
Chaudary’s
A plausible is homolytically (6-->7,
counterparts
4-dimethylaminopyridine mechanism cleaved
Barton-type
butyldimethylsilyl
to produce
reaction), acetal
catalyzed
an alkoxy
iodination.
acetals.
silylated
of
alkoxides
benzene,
NaHCO,,
c:
1. 5
ring closure
The initially formed Intramolecular
furnishes
0
V
35%
h-d
OTBS
4 -HI
N-l
1
0
HOFOTBS
0
I
N-H
6
c 0
5 hd
5
-I’
_
o/.,,/,,OTBS
*
by
group
6
4791
;
hypoiodite
I,5 hydrogen
the observed
1
3
l_O+.../,+OTBS
dials
as described hydroxyl
4.
&-W-VOTBS
this
Symmetrical
at the primary
radical and an iodine radical.
and nucleophilic
NIS,
of
procedure.3p4
is shown in Scheme
Scheme
0
an extension
diols via their monosodium were selectively
for this transformation
in the presence
hd
of mono-t-butyldimethylsilylated
to their mono-t-butyldimethylsilylated Their unsymmetrical
(NE)
benzene
reflux,
cyclization
with N-iodosuccinimide
HOFoTBS 7
t-
5
shift
4792
The results of our cyclitation worthy of note. corresponding constitutes
studies
These reactions simple
aliphatic
a regioselective
diol gets oxidized.
are shown in Table 1 .6 Several
take place under milder conditions alcohols.
oxidation
(entries 4 and
6).
The silylationloxidation
procedure
aspects of this oxidation
than are required sequence
in which the less substituted
It is thought that Table
are
for the
for prim-set
diols
(and protected)
end of the
the poor yield of the ketal shown in entry 5
1
l
Alcohol
Entry 1
Eq NIS
f&x+@bOTBS
Time (h)
1.7
2
1.5
Product(s)
V
6
Yield a 72%
0
OTBS
12
84% OTBS
3
1.5
6
63% + OTSS
6% OTBS 4
5
6
HO~OTBS
HO
&OTBS
OTBS
2.3
8
1.5
12
~OTBS
11%
2-6
VBS
7
HO-OTBS
87%
2.8
34
12%
60%
7%
aAll yields are isolated
except for entry 7 which were obtained
by gas chromatography.
4793
is due to the presence I-5
hydrogen
shM7
upon irradiation
of significant It is interesting
in the presence
1,3-syn
diaxial
moiety functions
Entry 6 shows that hydrogen incipient
carbon
illustrates abstraction transition
radical
the ability
abstraction
to the t-butyldimethylsiloxy
of the t-bulyldimelhylsiloxy
via a seven-membered state.
The stabilization
be viewed as an interaction singly occupied
carbon
Diastereomeric confirmation
p orbital.’
mixtures
to produce
Lewis acid mediated
group
It appears
cyclic transition
group
group
imparts
nonbonding
direct
fhe intramolecular six-membered
to an adjacent
carbon
Entry 7 hydrogen cyclic radical can
molecular orbital of the oxygen and the
g
of acetals were produced
in entries 2, 4, and 6. appropriate.
was deemed
the corresponding processes
known lactones (Scheme 2). of t-butyldimethylsilylated
In these cases further
These products
CrO,, &SO+, H,O
0
-78°C
-,
RT, 77%
OTBS
CrO,, -78“C
H,50,, --+
RT,
H,O
were thus subjected
to
In the future we plan to examine
acetals.
Scheme 2
cc
of the mechanism.
than an alkyl group.312
assignments
substitution
that the t-
shift portion
stale rather than the normal
a t-butyldimethylsiloxy
analogue
much more readily when the
to selectively
between the doubly occupied
of the structural
Jones oxidation
radical ocWs
state for the
only the aldehyde
t-butyldimethylsilyl
group for the hydrogen
by the alkoxy
transition
alcohol furnishes
The corresponding
upon reaction with NIS.
as a directing
is adjacent
in the chair-like
to note that o-methylbenzyl
of NIS in benzene. 1
(entry 3) affords the acetal as the major product butyldimethylsiloxy
interactions
=G
0 0
4794
lyrical
EQerimeotal
Procedure
To a solution
of cis-I -O-t-butyldimethylsilyl-l,2-cyclohexanedimethanol
entry 2) in benzene heterogenous
reaction
mixture
was irradiated
Water (5 mL) and Na2S203.H20 species.
The resultant
combined
organic extracts
reduced pressure. ethyl acetate colorless acetal
0.31
mmol,
(0.60 mmol).
was extracted
any NIS or hypoiodite
with a 50% ether in hexane
were then washed with water (5 ml),
The crude residue was chromatographed
mixture
The
lamp.
containing
(4 X 5 mL).
and the solvent was removed
The under
on a 35 X 1 cm column of silica gel with 1%
to afford 67 mg (0.26 mmol, 84% yield) of the corresponding
cyclic acetal as a
: 1 mixture of diastereomers at the acetal center as determined by integration of the 1H NMR signals). IR (neat) 2940. 2880, 1470, 1460, 1320, cm-l; 1 H NMR (60 MHz,
oil (1.6
5.4 (d, J = 2 Hz. IH.
2.1 (m, ZH), (MH+,
mg,
at 35OC for 12 h with a G.E. 150 W, 130 V tungsten
(0.5 g) were then added to destroy
mixture
in hexane
proton
CDCl3)
(80
(1.6 ml) was added 105 mg NIS (0.47 mmol) and 51 mg NaHC03
1.9-1.2
loo),
major diastereomer),
(m, 8H),
199
(8),
146
0.1 (s, H-l);
0.9 (s, 9H), (5),
125
5.2 (br s, lH,
minor diastereomer),
MS (Cl),
m/z
(relative
3.9 (m, 2H),
intensity)
257
(57).
Acknowledgements We are grateful to the Jessie Ball DuPont Religious, Chemistry
Fund of Berea College
to Steven Stout of American References 1.
and
Fund and the Julian Capps
a summer research grant for C.E.M.
for performing
Webb, M.;
R.; Bogardus,
Yates, S.
. We are also grateful
the mass spectral analyses.
C.; Champney,
2.
McDougal,
P.; Rico, J.; Oh, Y.: Condon,
Chaudary,
S.; Hernandez,
4.
All of the diols were commercially aluminum
hydride
Meystere,
C.; Heusler,
B.; Hii, P.; Reinking,
J. Org. Chem. 1983,
3.
5.
and Educational
notes
Beebe, T.; Adkins, W.;
for providing
Cyanamid
Charitable,
0.
reduction
J.;
Weatherford,
B. J. Org. Chem. 1986, 51, 3388.
Tetrahedron available
Leff., 1979, 20, 99. except
of gamma-octanoic
K.: Kalvoda,
P.; Shadday,
48, 3126.
for 1,5-octanediol
which was obtained
by
lithium
lactone.
J.; Wieland,
P.; Anner,
G.; Wettstein,
A. fxperentia,
1961,
17,
475. 6.
All starting materials and products were characterized
by IR,
1H NMR,
elemental
analysis
and/or
GUMS. 7.
The necessity previously,
8.
For an example van der Gen,
9.
Bernardi, 98,
of low-energy
see:
Heusler,
chair conformations
K.; Kalvoda,
of oxygen-directed, A. Tetrahedron
J. Angew.
regioselective
Lett. 1976,
F.; Epiotis, N.; Cherry,
for efficient
1,5hydrogen
shifts has been noted
Chem. Int. Ed. Engl. 1964, 3, 525. radical chlorination
see:
Kruse, C.; Broekhof,
W.; Schlegel, H.; Whangbo, M.; Wolfe, S. J. Am. Chem. Sot. 1976,
469.
IO. Viehe, H.; Merenyi, R.; Stella, L.; Janousek, 2. Angew Chem Int M fngl. (Received
in USA
19 May
N.;
17. 1725.
1989)
1979,
18, 917.