Selenoxides as catalysts for epoxidation and Baeyer-Villiger oxidation with hydrogen peroxide

Article abstract of DOI:10.1055/s-2006-939692

Aryl benzyl selenoxides are catalysts for the epoxidation of various olefinic substrates and the Baeyer-Villiger oxidation of aldehydes and ketones with H₂O₂ in CH₂Cl₂ at 2.5 mol% catalyst. Benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide (4) was the most effective catalyst while 2-(dimethylamino)phenyl benzyl selenoxide was the least. Mono-, di-, and trisubstituted alkenes were epoxidized and adamantanone, cyclohexanone, and 3,4,5-trimethoxybenzaldehyde underwent Baeyer-Villiger oxidation using 4 and H₂O₂. Competition studies showed that epoxidation reactions were faster than Baeyer-Villiger oxidations although the selectivity varied only from 1.3:1 to 4.6:1. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2006-939692

1100
LETTER
Selenoxides as Catalysts for Epoxidation and Baeyer–Villiger Oxidation with
Hydrogen Peroxide
S
elenoxides as Catalys
a
ts rgaret A. Goodman, Michael R. Detty*
Department of Chemistry, University at Buffalo, The State University of New York, 627 Natural Sciences Complex, North Campus,
Buffalo, New York 14260, USA
Fax +1(716)6456963; E-mail: mdetty@buffalo.edu
Received 14 February 2006
diphenyl selenoxide (Figure 1) were evaluated as cata-
Abstract: Aryl benzyl selenoxides are catalysts for the epoxidation
lysts for the epoxidation of alkenes with H2O2 in order to
examine electron-donating substituents (2), chelating
substituents (3), and electron-withdrawing substituents (4
of various olefinic substrates and the Baeyer–Villiger oxidation of
aldehydes and ketones with H2O2 in CH2Cl2 at 2.5 mol% catalyst.
Benzyl 3,5-bis(trifluoromethyl)phenyl selenoxide (4) was the most
effective catalyst while 2-(dimethylamino)phenyl benzyl selen- and 5) in the aryl group relative to either benzyl phenyl
oxide was the least. Mono-, di-, and trisubstituted alkenes were
epoxidized and adamantanone, cyclohexanone, and 3,4,5-tri-
methoxybenzaldehyde underwent Baeyer–Villiger oxidation using
4 and H2O2. Competition studies showed that epoxidation reactions
were faster than Baeyer–Villiger oxidations although the selectivity
varied only from 1.3:1 to 4.6:1.
selenoxide (1) or diphenyl selenoxide.
O
O
Se
2
NMe2
Se
Se
Ph
Ph
1
Ph
Key words: catalysis, epoxidations, esters, oxidations, selenoxide
MeO
Ph
O
3
O
O
F3C
Se
O
Hydrogen peroxide is an inexpensive, commercially
available strong oxidant that is environmentally benign.
Kinetically, many reactions of H2O2 are slow and require
the use of a catalyst to give useful rates of reaction. Two
reactions in which H2O2 has been a useful oxidant are
epoxidation of alkenes and Baeyer–Villiger oxidation of
aldehydes and ketones. Inorganic complexes of tungsten,1
rhenium,2 and manganese3 have been used as catalysts for
epoxidation reactions with H2O2 as have inorganic and
organic compounds of selenium such as selenium(IV)
oxide,4 arylseleninic acids,5 and their precursor di-
selenides.6,7 Both selenium(IV) oxide and arylseleninic
acids have been used as catalysts for Baeyer–Villiger
oxidations with H2O2.6,8,9 Among these catalysts, the
arylseleninic acids have perhaps been the most efficient.
Se
Ph
Se
4
5
Ph
Ph
O2N
CF3
Figure 1 Selenoxide catalysts for epoxidation and Baeyer–Villiger
oxidation with hydrogen peroxide
Benzyl aryl selenoxides 1–4 were prepared as previously
described.10 Benzyl 4-nitrophenyl selenoxide (5), which
has been prepared by singlet oxygen oxidation of benzyl
4-nitrophenyl selenide,12 was synthesized by NaBH4
reduction of bis(4-nitrophenyl)diselenide5c followed by
addition of benzylbromide to the resulting selenide anion
in ethanol. Oxidation of benzyl 4-nitrophenyl selenide
with m-chloroperbenzoic acid (MCPBA) gave selenoxide
5 in 73% overall yield. Diphenyl selenoxide was prepared
via oxidation of diphenyl selenide.13
We report that organoselenoxides are efficient catalysts
for epoxidation of alkenes as well as for Baeyer–Villiger
oxidation of carbonyl-containing compounds using H2O2
as an environmentally benign oxidant. We have previous-
ly shown that organoselenoxides are effective catalysts
for the bromination of organic substrates with NaBr and
H2O2 and that these catalysts are somewhat more active
than arylseleninic acid catalysts for this reaction.10
Selenoxides 1–5 and diphenyl selenoxide were evaluated
as catalysts using the epoxidation of cis-cyclooctene with
H2O2 to 9-oxa-bicyclo[6.1.0]nonane (6) as a model reac-
tion (Scheme 1).14 Pseudo-first-order rate constants k for
the first half-life of epoxidation (and their relative rates,
krel) are compiled in Table 1 and represent the average of
duplicate runs. A control reaction with no selenoxide gave
no detectable epoxidation after 72 hours at 296 K. If one
assumes a lower detection limit of 2% conversion to prod-
uct 6, then an upper limit for the rate of the uncatalyzed
reaction is still <10–7 s–1.
Diaryl, dibenzyl, and aryl benzyl selenoxides all lack b-
alkyl hydrogens to the selenoxide functionality, do not un-
dergo selenoxide elimination,11 and have shown catalytic
activity with H2O2.10 Among these systems, aryl benzyl
selenoxides have greater catalytic activity with H2O2 than
the diaryl or dibenzyl systems. Selenoxides 1–5 and
All of the benzyl selenoxides 1–5 exhibited some catalytic
activity for the epoxidation of cyclooctene to give 6
(Table 1). Diphenyl selenoxide gave no detectable epoxi-
dation after 72 hours. Interestingly, both benzyl 4-meth-
oxyphenyl selenoxide (2) and benzyl 4-nitrophenyl
SYNLETT 2006, No. 7, pp 1100–1104
0
3.
0
5.
2
0
0
6
Advanced online publication: 24.04.2006
DOI: 10.1055/s-2006-939692; Art ID: S01706ST
© Georg Thieme Verlag Stuttgart · New York

LETTER
Selenoxides as Catalysts
1101
selenoxide (5) were poorer catalysts than benzyl phenyl Several examples of preparative epoxidation are present-
selenoxide (1) suggesting that electronic effects do not ed in Scheme 2.15,16 Isolated yields are the average of du-
follow an obvious trend. Selenoxide 3 with a chelating plicate runs. Times given are for completion of reaction.
2-(dimethylaminomethyl)phenyl substituent was much The more highly substituted alkenes were the most reac-
less active as a catalyst for epoxidation with H2O2 (krel of tive substrates. Thus, epoxidations of the trisubstituted
0.007 for 3 vs. krel of 1 for 1, Table 1). Benzyl 3,5-bis(tri- alkenes 2-methyl-2-heptene and 1-methylcyclo-hexene
fluoromethyl)phenyl selenoxide (4) was the most active were complete within 4 hours to give 8 and 9, respective-
selenoxide evaluated as an epoxidation catalyst with ly, in 94% and 86% isolated yield. Epoxidations of the
H2O2. The 3,5-bistrifluoromethyl substituents behaved disubstituted alkenes cis-cyclooctene and (E)-5-decene
similarly in studies of aryl seleninic acids as catalysts for were somewhat slower but complete within 9 hours to
epoxidation with H2O2.5c We have no obvious explanation give 6 and 9, respectively, in 93% and 89% isolated
for the superior performance of these derivatives. The yields. Epoxidation of the monosubstituted 1-decene was
trends observed with selenoxides 3 and 4 for epoxidation sluggish at best and was only 15% complete after 24 hours
are opposite those observed in selenoxide-catalyzed (product not isolated). Epoxidation of (E)-2-methylsty-
brominations of organic substrates with H2O2.10 In the rene, with an electron-withdrawing (relative to an alkyl
bromination studies, benzyl 2-(dimethylaminometh- group) phenyl group on the alkene, also was relatively
yl)phenyl selenoxide (3) was the most active catalyst and slow and was only 75% complete after 24 hours. Epoxide
was 40 times more active than selenoxide 4, the least ac- 7 was isolated in 56% yield.
tive catalyst studied. For epoxidation of cis-cyclooctene,
though, selenoxide 4 is roughly 2000 times more active
than selenoxide 3 (Table 1).
O
cat. 4
+
H2O2
0.05 mmol
2.5 mol%
4 mmol
2 mmol
2 mL CH2Cl2
O
Se
Ar
1–5, 5 mol%
Ph
H
O
H
O
O
O
H2O2, CH2Cl2
8
7
6
Scheme 1 Epoxidation of cyclooctene with hydrogen peroxide
94%, 4 h
56%, 24 h
93%, 9 h
O
H
O
Table 1 Pseudo-First-Order Rate Constants k and Relative Rate
Constants krel for Selenoxide-Catalyzed Epoxidation of Cyclooctenea
10
89%, 9 h
H
O
9
86%, 4 h
Catalyst
k (s–1)
krel
11
15%, 24 h
None
<10–7
<0.001
<0.001
1.0
Scheme 2 Scope of epoxidation reactions
Ph2Se = O
<10–7
1
2
3
4
5
(7.6 0.1)·10–5
(9.2 0.1)·10–6
(5.3 0.2)·10–7
(1.0 0.1)·10–3
(2.2 0.1)·10–5
O
O
R
cat. 4
R'
+
H2O2
0.12
0.007
13
R
R'
O
0.05 mmol
2.5 mol%
2 mmol
2 mL CH2Cl2
4 mmol
MeO
MeO
MeO
MeO
O
H
0.29
MeO
MeO
O
H
a Conditions: 5 mol% selenoxide relative to cis-cyclooctene with
2 equiv H2O2 in CH2Cl2 at 296 1 K.
13
O
12
96%, 8 h
O
O
A series of control reactions were performed. Selenoxide
4 was evaluated as a stoichiometric reagent with cis-cy-
clooctene and no epoxidation was observed after stirring
a 1:1 mixture of the two for 24 hours in CH2Cl2. Selenox-
ide 4 gave no reaction with two equivalents of H2O2 after
24 hours. Specifically, no 3,5-bis(trifluoromethyl)phen-
ylseleninic acid was observed in the product mixture.
With tert-BuOOH as oxidant, no epoxidation of cyclo-
octene with selenoxide 4 was observed after 48 hours.
O
O
14
O
94 %, 24 h
O
15
98%, 18 h
Scheme 3 Baeyer–Villiger oxidations
Synlett 2006, No. 7, 1100–1104 © Thieme Stuttgart · New York

1102
M. A. Goodman, M. R. Detty
LETTER
The selenoxides of Figure 1 were also compared as cata- species such as 19 were involved in the rate-determining
lysts for Baeyer–Villiger oxidation of 3,4,5-trimethoxy- step of the oxidation where a formal positive charge
benzaldehyde (12) to formate 13 (Scheme 2).17 After 24 develops on the selenium atom adjacent to the aryl ring.
hours, chelating selenoxide 3 gave less than 10% reaction,
selenoxide 1 gave 50% reaction, selenoxides 2 and 5 gave
25% reaction, and selenoxide 4 gave essentially complete
conversion of 12 to formate 13. Diphenyl selenoxide gave
no detectable Baeyer–Villiger oxidation. These trends in
catalyst activity follow those observed with the epoxida-
tion reactions.
The epoxidation reactions and the Baeyer–Villiger oxida-
tions displayed no clear trend for the effect of selenoxide
substituents on rates of catalysis. Both selenoxide 2 with
an electron-donating 4-methoxyphenyl substituent and
selenoxide 5 with an electron-withdrawing 4-nitrophenyl
substituent were poorer catalysts than benzyl phenyl
selenoxide (1). These observations suggest that charge
Selenoxide 4 was evaluated in preparative Baeyer– development is not as important in the rate-determining
Villiger oxidations with aldehyde 12, cyclohexanone, or step, which is consistent, perhaps, with hydroxy per-
adamantanone and H2O2 as shown in Scheme 3.15,16 Iso- hydroxy selenane intermediate 16 as the active oxidant in
lated yields are the average of duplicate runs. Times given these systems relative to selenonium intermediate 19.
are for completion of reaction. For these three systems,
selenoxide 4 is an efficient and practical catalyst for pro-
ducing Baeyer–Villiger oxidation products in high yields.
Benzyl 2-[(dimethylamino)methyl]phenyl selenoxide (3)
was the poorest epoxidation or Baeyer–Villiger catalyst
among 1–5, yet 3 was the best catalyst for oxidation of
bromide with H2O2.10 As shown in Scheme 5, the 2-(di-
OH
methylamino)methyl substituent can chelate the Se(IV)
center to form selenane 21 from selenane 20. In related
product
Se
[ox]
Te-containing compounds, the chelated structure was
OH
– H2O
substrate
characterized by X-ray crystallography19a and rotational
17
O
barriers suggest N–Te interactions on the order of 14–15
H
–
OH
+
O
kcal mol–1.21 The Se–N interactions should be of similar
H2O2
Se
Se
magnitude in the selenoxide 3.
18
OH
product
16
–
HOBr
Br
O
O
H
[ox]
substrate
Me2N
+
+
Se
+
NMe2
OH
Se
fast
NMe2
19
Se
H+,
Se
Ph
Ph
Ph
Scheme 4 Two possible catalytic cycles for selenoxide catalysts
– H2O
OOH
21
OOH
–
OH
slow
20
3
The catalytic utility of the selenoxide functional group be-
gins with the addition of H2O2 to the selenoxide as shown
in Scheme 4. We have shown that H2O adds reversibly to
diphenyl selenoxide13 to give the trigonal bipyramidal di-
hydroxy selenane and that thiols can add reversibly to se-
lenoxides.18 The addition of H2O2 to the selenoxide
generates a hydroxy perhydroxy selenane intermediate
represented by 16 in Scheme 4. In the presence of H2O2
and H2O, both 16 and dihydroxy selenane 17 would be in
equilibrium with the selenoxide 18. Intermediate 16 may
behave similarly to peroxyseleninic acids and to percar-
boxylic acids with respect to transfer of the oxygen atom
to alkene or carbonyl-containing compound. Following
transfer of the oxygen atom, the dihydroxy selenane (16)
can reversibly lose water to regenerate the selenoxide and
begin the catalytic cycle anew. Alternatively, protonation
of 16 followed by loss of water would lead to the perhy-
droxyselenonium intemediate 19 (Scheme 4). We have
described kinetic evidence for the formation of hydroxy-
selenonium and haloselenonium intermediates from
selenoxides in several studies, which suggests that 19 is a
reasonable intermediate to propose for reactions of
selenoxides with H2O2.18–20 One might expect substituent
effects to be more pronounced if perhydroxyselenonium
alkene or
carbonyl compound
epoxide or
ester
Scheme 5
Perhydroxy selenane 21 presumably is the active oxidant
for either epoxidation or for oxidation of bromide using
catalytic selenoxide 3 with H2O2. If nucleophilic attack of
bromide on selenane 21 to produce 3 and HOBr as shown
in Scheme 5 were much faster than nucleophilic attack of
bromide on various hydroxy perhydroxy selenanes 16 or
perhydroxyselenonium species 19,10 then the increased
catalytic activity of 3 relative to other selenoxides in the
oxidation of bromide with H2O2 is easily rationalized.
Conversely, if rate-determining transfer of oxygen from
21 to alkene or carbonyl were much slower than rate-de-
termining transfer of oxygen from hydroxy perhydroxy
selenane 16, then 3 would be a poorer catalyst for epoxi-
dations or Baeyer–Villiger oxidations with H2O2.
Baeyer–Villiger oxidation and epoxidation can be com-
peting reactions in highly functionalized alkenes and a se-
lective procedure for either transformation when both
alkene and carbonyl functional groups are present would
offer synthetic advantages. We examined competition
Synlett 2006, No. 7, 1100–1104 © Thieme Stuttgart · New York

LETTER
Selenoxides as Catalysts
1103
(5) (a) Grieco, P. A.; Yokoyama, Y.; Gilman, S.; Nishizawa, M.
J. Org. Chem. 1977, 42, 2034. (b) Sharpless, K. B.; Hori, T.
J. Org. Chem. 1978, 43, 1689. (c) Ten Brink, G. J.;
Fernandes, B. C. M.; Van Vliet, M. C. A.; Arends, I. W. C.
E.; Sheldon, R. A. J. Chem. Soc., Perkin Trans. 1 2001, 224.
(6) Syper, L.; Mlochowski, J. Tetrahedron 1987, 43, 207.
(7) For a general review, see: Lane, B. S.; Burgess, K. Chem.
Rev. 2003, 103, 2457.
reactions between 1-methylcyclohexene and 3,4,5-tri-
methoxybenzaldehyde (12) or cyclohexanone using
selenoxide 2 or 4 as a catalyst.22 For comparison purposes,
we also examined the selectivity for epoxidation relative
to Baeyer–Villiger oxidation using m-chloroperbenzoic
acid (MCPBA) as oxidant with the same 1:1:1 relative
stoichiometry of oxidant and substrates.22
(8) (a) Ten Brink, G. J.; Vis, J.-M.; Arends, I. W. C. E.; Sheldon,
R. A. J. Org Chem. 2001, 66, 2429. (b) Ten Brink, G. J.;
Vis, J.-M.; Arends, I. W. C. E.; Sheldon, R. A. Tetrahedron
2002, 3977.
(9) For general reviews, see: (a) Renz, M.; Meunier, B. Eur. J.
Org. Chem. 1999, 737. (b) Krow, G. R. Org. React. 1993,
43, 251.
With m-CPBA, epoxidation of 1-methylcyclohexene was
favored by 16:1 relative to Baeyer–Villiger oxidation of
aldehyde 12 and by 20:1 relative to Baeyer–Villiger oxi-
dation of cyclohexanone. With H2O2 and selenoxide 4 as
a catalyst, epoxidation of 1-methyl-cyclohexene was fa-
vored by 4.0:1 relative to Baeyer–Villiger oxidation of al-
dehyde 12 and by 4.6:1 relative to oxidation of
cyclohexanone. With H2O2 as oxidant and benzyl 4-meth-
oxyphenyl selenoxide (2) as catalyst, epoxidation of 1-
methylcyclohexene was favored by 1.6:1 relative to
Baeyer–Villiger oxidation of aldehyde 12 and by 1.3:1
relative to oxidation of cyclohexanone.
(10) Goodman, M. A.; Detty, M. R. Organometallics 2004, 23,
3016.
(11) (a) Walter, R.; Roy, J. J. Org. Chem. 1970, 36, 2561.
(b) Jones, D. N.; Mundy, D.; Whitehouse, R. D. J. Chem.
Soc., Chem. Commun. 1970, 86. (c) Sharpless, K. B.;
Young, M. W.; Lauer, R. F. Tetrahedron Lett. 1973, 1979.
(d) Reich, H. J.; Reich, I. L.; Renga, J. M. J. Am. Chem. Soc.
1973, 95, 5813.
Aryl benzyl selenoxides are efficient catalysts for epoxi-
dation of alkenes and for Baeyer–Villiger oxidation of
various carbonyl-containing compounds using the envi-
ronmentally benign oxidant H2O2. Of the selenoxides ex-
amined here, selenoxide 4 is kinetically the most active
catalyst. Rates of Baeyer–Villiger oxidation and epoxida-
tion with the selenoxide catalysts are more similar than
with MCPBA as an oxidant where epoxidation is much
faster. We shall build upon these initial studies to develop
selective selenoxide catalysts for epoxidation of alkenes
or for Baeyer–Villiger oxidation of aldehydes and ketones
using H2O2 as an oxidant.
(12) Krief, A.; Lonez, F. Tetrahedron Lett. 2002, 43, 6255.
(13) Detty, M. R. J. Org. Chem. 1980, 45, 274.
(14) Hydrogen peroxide (8.8 M, 0.225 mL, 2.0 mmol) was added
to 1.0 mmol of cis-cyclooctene and 0.05 mmol of selenoxide
in 2 mL of CH2Cl2. The progress of the reaction at 296 1 K
was monitored by determining the cis-cylooctene:6 ratio
using 1H NMR spectroscopy from aliquots withdrawn from
the reaction mixtures.
(15) Selenoxide 4 (0.05 mmol, 2.5 mol%), alkene (2 mmol) or
carbonyl compound (2 mmol), and H2O2 (8.8 M, 0.45 mL,
4.0 mmol) were stirred in CH2Cl2 (2 mL) at 296 K. The
progress of reaction was followed by 1H NMR spectroscopy
of aliquots withdrawn at various time points. Upon
completion, reaction mixtures were poured into 10 mL of
H2O and products were extracted with CH2Cl2. Products
were purified via chromatography of SiO2 eluted with
CH2Cl2.
Acknowledgment
(16) Compound 6: 1H NMR (400 MHz, CDCl3): d = 2.91 (d, 2 H,
J = 8 Hz), 2.15 (d, 2 H, J = 11.6 Hz), 1.27–1.60 (m, 10 H).
13C NMR (125 MHz, CDCl3): d = 55.35, 26.58, 26.37, 25.59.
Compound 7: 1H NMR (400 MHz, CDCl3): d = 7.24–7.34
(m, 5 H), 3.57 (s, 1 H), 3.04 (q, 1 H, J = 5.0 Hz), 1.44 (d, 3
H, J = 5.0 Hz). 13C NMR (125 MHz, CDCl3): d = 137.60,
128.30, 127.90, 125.40, 59.42, 58.93, 17.80.
We thank the Office of Naval Research (Grant No. N00014021-
0836) for partial support of this work.
References and Notes
(1) (a) Allan, G. G.; Neogi, A. N. J. Catal. 1970, 16, 197.
(b) Venturello, C.; Alneri, E.; Ricci, M. J. Org. Chem. 1983,
48, 3831. (c) Ishii, Y.; Yamawaki, K.; Ura, T.; Yamada, H.;
Yoshida, T.; Ogawa, M. J. Org. Chem. 1988, 53, 3587.
(d) Kaczmarczyk, E.; Janus, E.; Milchert, E. J. Mol. Catal.
A: Chem. 2005, 235, 52.
(2) (a) Herrmann, W. A.; Fischer, R. W.; Scherer, W.; Rauch,
M. U. Angew. Chem., Int. Ed. Engl. 1993, 32, 1157.
(b) Rudolph, J.; Reddy, K. L.; Chiang, J. P.; Sharpless, K. B.
J. Am. Chem. Soc. 1997, 119, 6189. (c) Li, M.; Espenson, J.
H. J. Mol. Catal. A: Chem. 2004, 208, 123.
(3) (a) Renaud, J. P.; Battioni, P.; Bartoli, J. F.; Mansuy, D. J.
Chem. Soc., Chem. Commun. 1985, 888. (b) Neumann, R.;
Gara, M. J. Am. Chem. Soc. 1995, 117, 5066. (c) Rebelo, S.
L. H.; Pereira, M. M.; Simoes, M. M. Q.; Neves, M. G. P. M.
S.; Cavaleiro, J. A. S. J. Catal. 2005, 234, 76.
(4) (a) Astin, S.; Newman, A. C. C.; Riley, H. L. J. Chem. Soc.
1933, 391. (b) Schaefer, J. P.; Horvath, B.; Klein, H. P. J.
Org. Chem. 1968, 33, 2647.
Compound 8: 1H NMR (500 MHz, CDCl3): d = 2.75 (t, 1 H,
J = 7.5 Hz), 1.24–1.52 (m, 12 H), 0.91 (t, 3 H, J = 6.5 Hz).
13C NMR (125 MHz, CDCl3): d = 64.58, 58.48, 28.42, 28.25,
24.61, 22.34, 18.42, 13.78.
Compound 9: 1H NMR (500 MHz, CDCl3): d = 1.84–1.91
(m, 2 H), 1.63–1.69 (m, 2 H), 1.38–1.44 (m, 2 H), 1.30 (s, 3
H), 1.16–1.26 (m, 2 H). 13C NMR (125 MHz, CDCl3): d =
59.15, 32.57, 29.40, 24.26, 23.52, 19.56, 19.18.
Compound 10: 1H NMR (500 MHz, CDCl3): d = 2.66 (t, 2
H, J = 5.0 Hz), 1.35–1.54 (m, 12 H), 0.93 (t, 6 H, J = 7.0
Hz). 13C NMR (125 MHz, CDCl3): d = 58.53, 31.78, 28.12,
22.46, 13.92.
Compound 13: 1H NMR (400 MHz, CDCl3): d = 8.17 (s, 1
H), 6.28 (s, 2 H), 3.71 (s, 9 H). 13C NMR (125 MHz, CDCl3):
d = 159.20, 153.20, 145.60, 135.70, 98.32, 60.36, 55.72.
Compound 14: 1H NMR (400 MHz, CDCl3): d = 4.25 (t, 2
H, J = 4.6 Hz), 2.66 (t, 2 H, J = 5.2 Hz), 1.59–1.66 (m, 4 H),
1.40–1.50 (m, 2 H). 13C NMR (75 MHz, CDCl3): d = 175.90,
69.22, 34.66, 29.18, 27.42, 25.40.
Synlett 2006, No. 7, 1100–1104 © Thieme Stuttgart · New York

1104
M. A. Goodman, M. R. Detty
LETTER
Compound 15: 1H NMR (400 MHz, CDCl3): d = 4.40 (t, 1
H, J = 3.0 Hz), 2.97 (t, 1 H, J = 5.4 Hz), 1.67–2.04 (m, 12
H). 13C NMR (75 MHz, CDCl3): d = 178.3, 72.61, 40.71,
35.15, 33.09, 30.35, 25.23.
(20) You, Y.; Ahsan, K.; Detty, M. R. J. Am. Chem. Soc. 2003,
125, 4918.
(21) Detty, M. R.; Williams, A. J.; Hewitt, J. M.; McMillan, M.
Organometallics 1995, 14, 5258.
(17) H2O2 (8.8 M, 0.225 mL, 2.0 mmol) was added to 1.0 mmol
of 12 and 0.05 mmol of selenoxide (5.0 mol% relative to 12)
in 2 mL CH2Cl2.
(18) Detty, M. R.; Friedman, A. E.; Oseroff, A. J. Org. Chem.
1994, 59, 8245.
(19) (a) Detty, M. R.; Friedman, A. E.; McMillan, M.
Organometallics 1994, 13, 3338. (b) Detty, M. R.;
Friedman, A. E.; McMillan, M. Organometallics 1995, 14,
1442.
(22) H2O2 (8.8 M, 0.225 mL, 2.0 mmol) or MCPBA (2.0 mmol,
no catalyst), 2.0 mmol of 1-methylcyclohexene, 2.0 mmol of
aldehyde 12 or cyclohexanone, and 0.05 mmol of selenoxide
were stirred in 2 mL of CDCl3. The reactions were stirred for
24 h and the product mixtures were examined directly by 1H
NMR spectroscopy. In each reaction, the product/starting
material ratio was approximately 1:1. Ratios are the average
of duplicate runs.
Synlett 2006, No. 7, 1100–1104 © Thieme Stuttgart · New York