Syntheses and reactions of new optically active terpene dialkyl diselenides

Article abstract of DOI:10.1002/ejoc.200600044

The reaction of sodium diselenide with optically active alkyl tosylates or chlorides is found to be a useful method for the synthesis of optically active dialkyl diselenides. Optically active monoterpene diselenides derived from menthane, carane, pinane,

Full text of DOI:10.1002/ejoc.200600044

FULL PAPER
DOI: 10.1002/ejoc.200600044
Syntheses and Reactions of New Optically Active Terpene Dialkyl Diselenides
[a]
[a]
[a]
´
Jacek Scianowski,* Zbigniew Rafin´ski, and Andrzej Wojtczak
Keywords: Terpenoids / Selenium / Electrophilic addition / Asymmetric synthesis
The reaction of sodium diselenide with optically active alkyl
tosylates or chlorides is found to be a useful method for the
synthesis of optically active dialkyl diselenides. Optically
active monoterpene diselenides derived from menthane, car-
ane, pinane, and bornane systems have been obtained. The
influence of the terpene fragment of the obtained diselenides
on the diastereomeric excess of the methoxyselenylation
products has been investigated. The best result for methoxy-
selenylation was observed for (–)-diisopinocamphyl diselen-
ide.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
Introduction
Results and Discussion
In recent years the synthetic[1] and pharmacological[2]
role of organoselenium compounds has been increasingly
appreciated. This great interest in organoselenium chemis-
try, especially in the reactions of optically active diselen-
ides,[3] prompted us to search for a useful method for the
synthesis of optically active terpene dialkyl diselenides.
The only terpenes extensively studied so far are optically
active diselenides that are camphor derivatives. These dis-
elenides were obtained either by oxidation of the reaction
products of organometallic compounds with selenium,[4]
the reaction of selenocyanates with samarium iodide,[5] or
the reaction of bromides with sodium diselenide.[6] Op-
tically active diselenides derived from camphor have been
used, for example, in methoxy- and hydroxyselenylation re-
actions and in selenocyclizations, amongst others.[4–6]
In a previous paper we proposed a new method for the
synthesis of dialkyl diselenides based on the reaction of
alkyl tosylates with sodium diselenide, and we successfully
employed this method for the synthesis of optically active
bis(cis-myrtanyl) diselenide (1; Scheme 1).[7]
This research began with the synthesis of menthane di-
selenides. The reactions were conducted as a one-step ver-
sion.[7] Treatment of (–)-menthol (2) with tosyl chloride in
pyridine[8] led to (–)-menthyl tosylate (3), which gave (+)-
dineomenthyl diselenide (4) upon treatment with sodium
diselenide (Scheme 2).
Scheme 2. Synthesis of (+)-dineomenthyl diselenide (4) and (–)-di-
menthyl diselenide (6). Reagents and conditions: a) TsCl, pyridine,
24 h, 0 °C; b) NaOH, Se, N2H4·H2O, DMF, Ar, 1 h, 100 °C; c)
CCl4, PPh3, 24 h, reflux; d) NaOH, Se, N2H4·H2O, DMF, Ar, 2 h,
100 °C.
Scheme 1. Synthesis of bis(cis-myrtanyl) diselenide (1).
We present here a synthesis of optically active diselenides
derived from menthane, carane, pinane, and bornane sys-
tems based on the reaction of sodium diselenide with alkyl
tosylates or chlorides. The resulting diselenides have been
investigated in the methoxyselenylation reaction.
The structure of 4 (Figure 1) was confirmed by an X-ray
crystallographic analysis.[9]
The absolute configurations at C-1 and C-1Ј were estab-
lished as S,S, which confirms the SN2 substitution mecha-
nism of the toluenesulfonyl group by sodium diselenide.
The diselenide bridge torsion angle C(1)–Se(1)–Se(2)–C(1Ј)
is –112.1(4)°. The cyclohexyl rings in both neomentyl moie-
ties have a chair conformation.
[a] Department of Chemistry, Nicolaus Copernicus University,
7 Gagarin Street, 87-100 Torun, Poland,
E-mail: jsch@chem.uni.torun.pl
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Optically Active Terpene Dialkyl Diselenides
FULL PAPER
Table 1. Synthesis of diselenides 15–19.
Figure 1. X-ray structure of (+)-dineomenthyl diselenide (4). Se-
lected bond lengths [Å] and angles [°]: Se(1)–Se(2) 2.3182(11),
Se(1)–C(1) 2.008(8), Se(2)–C(1Ј) 1.990(7); C(1)–Se(1)–Se(2)
100.6(2) C(1Ј)–Se(2)–Se(1) 100.05(18).
(+)-Neomenthyl chloride (5) was obtained as a result of
the reaction of (–)-menthol with CCl4 and PPh3.[10] When
treated with sodium diselenide, chloride 5 gave (–)-dimen-
thyl diselenide (6). Diselenide 6 could also be obtained from
the reaction of sodium diselenide with (+)-neomenthyl tos-
ylate (7), which was itself formed from (+)-neomenthol (8;
Scheme 2). Analogous reactions were conducted with (+)-
menthol to give (–)-dineomenthyl and (+)-dimenthyl dis-
elenides, respectively.
Subsequent studies on the synthesis of optically active
diselenides were carried out on the bicyclic terpene systems
using (–)-trans-4-caranol,[11] (–)-isopinocampheol,[12] and
(–)-borneol. The respective tosylates 9, 11, and 13, and the
chlorides 10 and 12 were obtained by the methods de-
scribed above.[8,10] Because of the instability of the bicyclic
terpene tosylates, which undergo spontaneous decomposi-
tion even at room temperature, the diselenides were ob-
tained in a two-step procedure. The respective tosylate or
chloride was added to the sodium diselenide prepared in
the first step (NaOH, Se, N2H4·H2O, DMF, Ar, 100 °C,
15 minutes). The syntheses of (+)-bis(cis-4-caranyl) diselen-
ide (15), (–)-bis(trans-4-caranyl) diselenide (16), (+)-dipino-
camphyl diselenide (17), (–)-diisopinocamphyl diselenide
(18), and (–)-diisobornyl diselenides (19) are presented in
Table 1. The structures of all diselenides obtained were es-
tablished on the basis of their 1H, 13C, and 77Se NMR spec-
tra.
[a] See ref.[8] [b] See ref.[10]
The addition of the selenic electrophile to a double bond,
conducted in methanol, proceeds as a two-stage process, na-
mely formation of a seleniranic ion and subsequent reaction
with a nucleophile (Scheme 3).
(–)-Dipinocamphyl and (+)-diisopinocamphyl diselenides
were also obtained from (+)-isopinocampheol. The synthe-
sis of diselenide from isobornyl chloride failed.
Scheme 3. Mechanism of methoxyselenylation.
The optically active selenic electrophiles hitherto ob-
The optically active terpene diselenides were used for the tained were synthesized in the process of reaction of sele-
asymmetric electrophilic methoxyselenylation. All chiral nides with bromine,[4d] sulfuryl chloride,[4a–4d,4f,4j,4l] or am-
diselenides used in the methoxyselenylation reactions de- monium persulfate.[4d,4g,4h] A bromide is usually changed
scribed so far have contained heteroatoms, which control for a triflate anion by treatment with silver triflate.[4d,4e,4i,4f]
–
–
the diastereomeric excess of the resulting products. There is PF6 and BF4 have also been used as counterions.[4f]
much theoretical and experimental evidence concerning the
The preliminary studies on the choice of the reaction
influence of heteroatoms in the literature.[3,4] So, for com- conditions were conducted with (+)-dineomenthyl diselen-
parison, we decided to investigate the influence of the struc- ide (4; Scheme 4). We investigated the influence of the sol-
ture of the unfunctionalized terpene diselenides on the dia- vent, the temperature, and the kind of counterion on the
stereomeric excess of the formed adducts in the methoxy- yield and the diastereomeric excess for the addition to sty-
selenylation.
rene.
Eur. J. Org. Chem. 2006, 3216–3225
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´
J. Scianowski, Z. Rafin´ski, A. Wojtczak
FULL PAPER
Scheme 4. Addition of bromide 9 to styrene in the presence of methanol.
For this purpose, we used THF, tert-butyl methyl ether, Table 4. Influence of temperature and counterion on the methoxy-
selenylation with (–)-dimenthyl diselenide (6).
and dichloromethane as solvents (Table 2). The best results
were obtained for dichloromethane. In the case of tert-butyl
methyl ether, the process was conducted at 0 °C because at
lower temperatures the reaction failed.
Counterion
Temp. [°C] Time [h]
Yield [%]
dr[a]
Br–
–78
–95
–78
2
3
2
11
90
80
56:44
65:35
62:38
OTf–
Table 2. Influence of solvent on the diastereomeric excess of the
methoxyselenylation with (+)-dineomenthyl diselenide.
1
[a] Estimated on the basis of H NMR spectroscopy.
Solvent
Temp. [°C]
Time [h]
Yield [%]
dr[a]
THF
tBuOMe
–78
–78
0
6
6
6
2
62
0
72
93
50:50
–
52:48
70:30
On the basis of the obtained results we conducted subse-
quent methoxyselenylation reactions in dichloromethane
at –78 °C using the triflate anion as a counterion. For these
methoxyselenylations we used diselenides derived from
menthane (4 and 6), carane (15 and 16), and pinane (17
and 18), as well as bis(cis-myrtanyl) diselenide (1). Styrene,
α-methylstyrene, β-trans-methylstyrene, and 1-methylcy-
clopentene served as alkenes (Table 5). The methoxyselenyl-
ation products 20–47 were isolated by column chromatog-
raphy and their diastereomeric excess was estimated by me-
CH2Cl2
–78
1
[a] Estimated on the basis of H NMR spectroscopy.
The investigation of the influence of the temperature and
counterion on the ratio of the produced diastereomers for
the reaction conducted in dichloromethane was the subse-
quent step of our study (Table 3). The best diastereomeric
excesses were obtained at –78 °C both for a bromide ion
and a triflate. The lowering of the reaction temperature in
the case of the bromide ion to –95 °C diminished the prod-
uct yield. A similar drop in yield was observed for the tri-
flate ion. A lowering of the diastereomeric excess was also
observed in both cases with a decrease of temperature. The
use of sulfuryl chloride and ammonium persulfate was un-
successful.
1
ans of H NMR spectroscopy. The pure compounds were
isolated in all cases except for the reaction of cis-caranyl
and pinocamphyl diselenides with β-trans-methylstyrene 37
and 40 (Table 5), whose purification by means of chromato-
graphic techniques led to partial decomposition. In this
1
case the diastereomeric excess was established from the H
NMR spectrum of the crude mixtures. The best dia-
stereomeric excess was obtained for the menthyl and pinane
diselenides. Much worse results were observed for cis-car-
anyl, trans-caranyl, and myrtanyl diselenides. The studies
with the (+)-diisobornyl diselenide (19) failed because of its
instability under the reaction conditions and spontaneous
decomposition.
Table 3. Influence of temperature and counterion on the methoxy-
selenylation with (+)-dineomenthyl diselenide (4).
Counterion
Br–
Temp. [°C]
Time [h]
Yield [%]
dr[a]
–95
–78
–95
–78
–78
25
3
2
3
2
2
24
6
43
93
48
60:40
70:30
60:40
70:30
–
–
–
OTf–
86
Cl–
HSO4
no reaction
no reaction
no reaction
– [b]
Conclusions
40
1
[a] Estimated on the basis of H NMR spectroscopy. [b] The reac-
tions were carried out with the addition of trifluoromethanesul-
fonic acid.
A series of new, optically active dialkyl diselenides have
been obtained by treatment of optically active alkyl tosyl-
ates and chlorides derived from mono- and bicyclic terpenes
For comparison, we also investigated the influence of with sodium diselenide. The obtained diselenides have been
counterion and temperature for (–)-dimenthyl diselenide (6) used with success as selenic electrophiles for asymmetric
(Table 4). The position of a diselenide group in a trans rela- methoxyselenylation. The best results were observed for
tion to an isopropyl group exerts a radical influence on the (–)-diisopinocamphyl diselenide (18), which shows that the
reaction rate. In the case of bromide ion for the reaction structure of the diselenides has a strong influence on the
conducted at –78 °C we observed mainly the bromoselenyl- diastereomeric excess of the formed adducts. Further inves-
ation product, whereas for the triflate ion the methoxyselen- tigation of the functionalization of these terpene diselenides
ylation product dominated. A change of temperature did and the influence on the diastereomeric excess of the re-
not influence the diastereomeric excess.
sulting products is in progress.
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Optically Active Terpene Dialkyl Diselenides
FULL PAPER
Table 5. Asymmetric methoxyselenylation of olefins with menthyl, pinanyl, and caranyl diselenides.
1
1
[a] Ter*: terpene fragment. [b] Estimated on the basis of H and 77Se NMR spectroscopy. [c] Estimated on the basis of H NMR spec-
troscopy of the crude product.
stirred for 1 h at the same temperature. It was then poured into
water (100 mL) and the resulting precipitate was filtered off and
dried under vacuum. The crude product was used without further
Experimental Section
1
General: H and 13C NMR spectra were recorded with Bruker Av-
ance 300 or Varian Gemini 200 spectrometers at 300, 200, 75, and
50.3 MHz, respectively (J values are given in Hz). 77Se NMR spec-
tra were recorded with a Varian Gemini 200 instrument at 38 MHz.
Optical rotations were measured in 50-mm cells with a polAAr
3000 polarimeter. All melting points are uncorrected. Elemental
analysis was carried out with a vario MACRO elemental analyzer.
Column chromatography was performed with Merck silica gel 60
(70–230 mesh) or basic alumina. Methanol and dichloromethane
were distilled from calcium hydride. Commercial grade N,N-di-
methylformamide was used without purification. All methoxyselen-
ylation reactions were carried out under an argon atmosphere. The
same general procedure as given for entries 2 and 3 of Table 5 be-
low was employed for all reactions in Tables 2–4, using styrene,
with the variations indicated in these tables. Diastereomeric ex-
cesses were measured by integration of the 1H NMR signals of the
methoxy groups, which were generally well-separated for the two
diastereomers, or by integration of the 77Se NMR signals.
purification.
(–)-Menthyl Tosylate (3): Yield: 25.6 g (75%), white solid; m.p. 95–
97 °C. [α]2D0 = –72.79 (c = 6.04, CHCl3). 1H NMR (200 MHz,
3
CDCl3, 25 °C): δ = 7.80 (d, JH,H = 8.0 Hz, 2 H, 2×CH), 7.32 (d,
3JH,H = 8.0 Hz, 2 H, CH), 4.40 (dt, JH,H = 10.6 and 4.4 Hz, 1 H,
3
CH), 2.44 (s, 3 H, CH3), 2.15 (m, 1 H, CH), 1.89 (m, 1 H, CH),
3
1.69–0.93 (m, 7 H), 0.87 (d, JH,H = 6.2 Hz, 3 H, CH3), 0.83 (d,
3JH,H = 7.0 Hz, 3 H, CH3), 0.52 (d, JH,H = 7.0 Hz, 3 H, CH3)
3
ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ = 144.2, 134.8, 129.6
(2 C), 127.7 (2 C), 83.6, 47.6, 41.9, 33.7, 31.6, 25.4, 22.9, 21.8, 21.5,
20.8, 15.2 ppm.
(+)-Neomentyl Tosylate (7): Yield: 15.7 g (46%), white solid; m.p.
59–62 °C. [α]2D0 = –25.10 (c = 3.20, CHCl3). 1H NMR (200 MHz,
3
CDCl3, 25 °C): δ = 7.82 (d, JH,H = 8.0 Hz, 2 H, 2×CH), 7.31 (d,
3JH,H = 8.0 Hz, 2 H, CH), 5.01 (m, 1 H), 2.44 (s, 3 H, CH3), 1.75
3
3
Preparation of Tosylates. General Procedure: Tosyl chloride
(110 mmol) was added in one portion to a solution of the terpene
alcohol (100 mmol) in pyridine (125 mL). The reaction mixture was
(m, 9 H), 0.83 (d, JH,H = 6.6 Hz, 3 H, CH3), 0.78 (d, JH,H =
6.6 Hz, 3 H, CH3), 0.75 (d, JH,H = 7.0 Hz, 3 H, CH3) ppm. 13C
3
NMR (50 MHz, CDCl3, 25 °C): δ = 144.1, 135.3, 129.5 (2 C), 127.5
Eur. J. Org. Chem. 2006, 3216–3225
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J. Scianowski, Z. Rafin´ski, A. Wojtczak
FULL PAPER
(2 C), 81.6, 47.8, 39.6, 34.4, 28.5, 25.8, 24.1, 21.8, 21.5, 20.6,
20.5 ppm.
zine hydrate (0.6 mL) dropwise to a mixture of selenium (22 mmol)
and sodium hydroxide (33 mmol) in DMF (20 mL). After heating
at 100 °C for 15 min, the reaction mixture was cooled to ambient
temperature and the respective tosylate (22 mmol) or chloride
(22 mmol) was added. The solution was heated again at 100 °C for
1 h (2 h for chlorides). The reaction mixture was cooled, poured
into water (100 mL), and extracted with petroleum ether
(3×100 mL). The combined ethereal layers were washed with water
(100 mL), dried with anhydrous MgSO4, and the solvents evapo-
rated. The product was purified by column chromatography (petro-
leum ether, silica gel). The structures of all diselenides obtained
were established on the basis of their 1H, 13C, and 77Se NMR spec-
tra.
(–)-trans-4-Caranyl Tosylate (9): Yield: 29.4 g (86%), white solid;
m.p. 42–43 °C. [α]2D0 = –46.17 (c = 8.65, CHCl3). 1H NMR
3
(300 MHz, CDCl3, 25 °C): δ = 7.77 (d, JH,H = 8.4 Hz, 2 H,
2×CH), 7.32 (d, 3JH,H = 8.4 Hz, 2 H, 2×CH), 4.10–3.97 (m, 1 H),
2.44 (s, 3 H, CH3), 2.19–1.34 (m, 5 H), 0.93 (s, 3 H, CH3), 0.88 (s,
3 H, CH3), 0.84–0.79 (m, 1 H), 0.74 (d, 3JH,H = 6.4 Hz, 3 H, CH3),
0.70–0.61 (m, 1 H) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ =
144.3, 134.8, 129.6 (2 C), 127.7 (2 C), 87.5, 34.0, 28.4, 28.2, 27.8,
21.6, 21.4, 19.7, 17.8, 17.7, 15.8 ppm.
(–)-Isopinocamphyl Tosylate (11): Yield: 22.2 g (65%), white solid;
m.p. 58–60 °C. [α]2D0 = –36.50 (c = 7.80, CHCl3). 1H NMR
(+)-Dineomenthyl Diselenide (4): Yield: 4.3 g (90%), yellow crystals;
m.p. 57–59 °C. [α]2D0 = +302.15 (c = 5.58, CHCl3). 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 3.64 (m, 2 H, 2×CH), 2.32 (m, 2
H, 2×CH), 2.02–1.55 (m, 10 H), 1.40–1.04 (m, 6 H), 0.97 (d, 3JH,H
3
(300 MHz, CDCl3, 25 °C): δ = 7.82 (d, JH,H = 8.4 Hz, 2 H,
3
2×CH), 7.34 (d, JH,H = 8.4 Hz, 2 H, 2×CH), 4.81–4.71 (m, 1 H,
CH), 2.44 (s, 3 H, CH3), 2.40–2.11 (m, 3 H), 1.98–1.74 (m, 3 H),
3
1.18 (s, 3 H, CH3), 1.05 (d, JH,H = 10.0 Hz, 1 H, CH), 0.89 (d,
3
= 6.4 Hz, 6 H, 2×CH3), 0.91 (d, JH,H = 6.6 Hz, 6 H, 2×CH3),
3JH,H = 7.4 Hz, 3 H, CH3), 0.85 (s, 3 H, CH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): δ = 144.4, 134.5, 129.7 (2 C), 127.8 (2 C),
83.0, 47.5, 44.0, 42.6, 38.2, 41.3, 35.8, 32.2, 23.9, 21.6, 19.6 ppm.
3
0.90 (d, JH,H = 6.4 Hz, 6 H, 2×CH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C): δ = 51.7 (2 C), 49.6 (2 C), 41.9 (2 C), 35.4 (2 C),
31.3 (2 C), 27.4 (2 C), 26.7 (2 C), 22.1 (2 C), 21.0 (2 C), 20.8 (2 C)
ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ = 290.4 ppm.
C20H38Se2 (436.44): calcd. C 55.04, H 8.77; found C 55.08, H 8.82.
(–)-Bornyl Tosylate (13): Yield: 23.5 g (69%), white solid; m.p. 74–
76 °C. [α]2D0 = –11.24 (c = 10.05, CHCl3). 1H NMR (200 MHz,
3
CDCl3, 25 °C): δ = 7.78 (d, JH,H = 8.2 Hz, 2 H, 2×CH), 7.32 (d,
(–)-Dimenthyl Diselenide (6): Yield: 1.9 g (40%), yellow oil. [α]2D0
= –306.27 (c = 5.10, CHCl3). 1H NMR (200 MHz, CDCl3, 25 °C):
3JH,H = 8.2 Hz, 2 H, 2×CH), 4.60 (m, 1 H, CH), 2.44 (s, 3 H,
CH3), 2.20–2.02 (m, 1 H, CH), 1.98–1.58 (m, 3 H), 1.34–1.21 (m,
3
δ = 2.85 (dt, JH,H = 11.2 and 3.8 Hz, 2 H, 2×CH), 2.42–2.22 (m,
2
3
2 H), 1.18 (dd, JH,H = 9.8, JH,H = 3.2 Hz, 2 H, CH2), 0.82 (s, 3
H, CH3), 0.80 (s, 3 H, CH3), 0.71 (s, 3 H, CH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): δ = 144.3, 134.3, 129.6 (2 C), 127.7 (2 C),
87.9, 49.5, 47.5, 44.6, 36.0, 27.7, 26.5, 21.5, 19.6, 18.6, 12.8 ppm.
3
4 H), 1.73–0.98 (m, 14 H), 0.91 (d, JH,H = 7.2 Hz, 6 H, 2×CH3),
3
3
0.90 (d, JH,H = 6.2 Hz, 6 H, 2×CH3), 0.77 (d, JH,H = 7.2 Hz, 6
H, 2×CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ = 47.9 (2
C), 47.7 (2 C), 45.4 (2 C), 34.8 (2 C), 34.4 (2 C), 29.1 (2 C), 24.9
(2 C), 22.2 (2 C), 21.4 (2 C), 15.3 (2 C) ppm. 77Se NMR (38 MHz,
CDCl3, 25 °C): δ = 336.3 ppm. C20H38Se2 (436.44): calcd. C 55.04,
H 8.77; found C 55.04, H 8.85.
Preparation of Chlorides. General Procedure: A solution of the ter-
pene alcohol (100 mmol) and triphenylphosphane (200 mmol) in
carbon tetrachloride (240 mL) was refluxed for 24 h. It was then
cooled and petroleum ether (300 mL) was added. The formed pre-
cipitate was filtered off under vacuum, concentrated, and evapo-
rated by means of a rotary evaporator. The product was isolated
by distillation under reduced pressure.
(+)-Bis(cis-4-caranyl) Diselenide (15): Yield: 4.6 g (95%), yellow oil.
[α]2D0 = +140.95 (c = 10.85, CHCl3). H NMR (300 MHz, CDCl3,
1
25 °C): δ = 3.39–3.46 (m, 2 H), 2.34–2.44 (m, 2 H), 1.77–1.91 (m,
4 H), 1.50–1.60 (m, 2 H), 1.00 (s, 6 H, CH3), 0.99 (s, 6 H, 2×CH3),
(+)-Neomenthyl Chloride (5): Yield: 14.8 g (85%), colorless liquid.
[α]2D0 = +53.03 (c = 9.05, CHCl3). 1H NMR (300 MHz, CDCl3,
25 °C): δ = 4.52 (m, 1 H), 2.08–2.03 (m, 1 H), 1.98–1.86 (m, 1 H),
1.77–1.69 (m, 2 H), 1.59–1.51 (m, 2 H), 1.42–1.30 (m, 2 H), 1.08–
3
0.96 (d, JH,H = 7.2 Hz, 6 H, 2×CH3), 0.77–0.90 (m, 2 H), 0.56–
0.71 (m, 4 H) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ = 49.5
(2 C), 31.4 (2 C), 28.5 (2 C), 26.4 (2 C), 25.8 (2 C), 21.5 (2 C), 21.4
(2 C), 20.1 (2 C), 17.8 (2 C), 15.9 (2 C) ppm. 77Se NMR (38 MHz,
CDCl3, 25 °C): δ = 351.1 ppm. C20H34Se2 (432.40): calcd. C 55.55,
H, 7.92; found C 55.56, H 7.86.
3
3
1.00 (m, 1 H) 0.93 (d, JH,H = 6.6 Hz, 3 H, CH3), 0.91 (d, JH,H
=
6.6 Hz, 3 H, CH3), 0.88 (d, JH,H = 6.6 Hz, 3 H, CH3) ppm. 13C
NMR (50 MHz, CDCl3, 25 °C): δ = 63.3, 48.9, 43.2, 34.8, 30.0,
25.8, 24.2, 21.8, 20.7, 20.1 ppm.
3
(–)-Bis(trans-4-caranyl) Diselenide (16): Yield: 3.4 g (70%), yellow
oil. [α]2D0 = –140.95 (c = 7.85, CHCl3). 1H NMR (300 MHz, CDCl3,
25 °C): δ = 2.54 (m, 2 H), 2.05 (m, 6 H), 1.32 (m, 2 H), 1.02 (d,
3JH,H = 6.3 Hz, 6 H, 2×CH3), 0.97 (s, 6 H, 2×CH3), 0.95 (s, 6 H,
2×CH3), 0.74 (m, 6 H) ppm. 13C NMR (50 MHz, CDCl3, 25 °C):
δ = 49.8 (2 C), 34.9 (2 C), 29.9 (2 C), 29.5 (2 C), 28.9 (2 C), 21.9
(2 C), 21.1 (2 C), 20.7 (2 C), 17.6 (2 C), 15.6 (2 C) ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): δ = 366.9 ppm. C20H34Se2 (432.40):
calcd. C 55.55, H 7.92; found C 55.52, H 7.90.
(+)-cis-4-Caranyl Chloride (10): Yield: 11.3 g (66%), colorless li-
quid. [α]2D0 = +26.76 (c = 12.45, CHCl3). 1H NMR (300 MHz,
CDCl3, 25 °C): δ = 4.32–4.24 (m, 1 H), 2.63–2.46 (m, 1 H), 1.90
3
(dt, JH,H = 16.8 and 3.0 Hz, 1 H, CH), 1.72–1.56 (m, 2 H), 1.08
3
(s, 3 H, CH3), 0.97 (d, JH,H = 6.4 Hz, 3 H, CH3), 1.07–0.76 (m, 2
3
H), 0.41 (dt, JH,H = 9.2 and 3.0 Hz, 1 H, CH) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): δ = 63.6, 34.0, 29.2, 28.7, 23.0, 22.1, 19.0,
17.8, 17.6, 15.9 ppm.
(–)-Dipinocamphyl Diselenide (17): Yield: 3.1 g (64%), yellow oil.
[α]2D0 = –9.69 (c = 52.04, CHCl3). 1H NMR (200 MHz, CDCl3,
25 °C): δ = 4.03–4.19 (m, 2 H), 2.49–2.75 (m, 4 H), 1.90–2.44(m, 8
H), 1.34 (d, 3JH,H = 10.0 Hz, 2 H, 2×CH), 1.22 (d, 3JH,H = 7.8 Hz,
6 H, 2×CH3), 1.19 (s, 6 H, 2×CH3), 1.01 (s, 6 H, 2×CH3) ppm.
13C NMR (50 MHz, CDCl3, 25 °C): δ = 48.9 (2 C), 42.1 (2 C), 40.6
(2 C), 39.6 (2 C), 38.6 (2 C), 36.8 (2 C), 28.2 (2 C), 27.6 (2 C), 23.4
(2 C), 19.8 (2 C) ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ =
352.2 ppm. C20H34Se2 (432.40): calcd. C 55.55, H 7.92; found C
55.35, H 8.10.
(+)-Pinocamphyl Chloride (12): Yield: 7.7 g (45%), colorless liquid.
[α]2D0 = +24.66 (c = 20.00, EtOH). 1H NMR (300 MHz, CDCl3,
25 °C): δ = 4.71 (dt, JH,H = 9.9 and 7.8 Hz, 1 H, CH), 2.71–2.57
3
3
(m, 2 H), 2.25–2.17 (m, 2 H), 2.00–1.86 (m, 2 H), 1.25 (d, JH,H
=
3
7.2 Hz, 1 H, CH), 1.21 (d, JH,H = 7.8 Hz, 3 H, CH3), 1.20 (s, 3 H,
CH3), 1.06 (s, 3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C):
δ = 55.8, 48.4, 41.5, 39.6, 39.4, 38.7, 28.5, 27.3, 23.1, 18.3 ppm.
Preparation of Diselenides. General Procedure: The standard syn-
thesis of diselenides was conducted under argon, by adding hydra-
3220
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 3216–3225

Optically Active Terpene Dialkyl Diselenides
FULL PAPER
(+)-Diisopinocamphyl Diselenide (18): Yield: 1.5 g (32%), yellow oil.
[α]2D0 = +98.11 (c = 7.95, CHCl3). 1H NMR (300 MHz, CDCl3,
25 °C): δ = 3.45 (m, 2 H), 2.55 (m, 2 H), 1.92 (m, 12 H), 1.20 (s, 6
56.8, 46.0, 42.1, 35.4, 31.1, 30.9, 27.6, 26.8, 22.2, 21.0, 20.9 ppm;
minor diastereomer: δ = 84.4, 45.9, 42.0, 30.8 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 148.9 ppm;
minor diastereomer: δ = 146.2 ppm. C19H30OSe (353.40): calcd. C
3
H, 2×CH3), 1.15 (d, JH,H = 7.2 Hz, 6 H, 2×CH3), 1.02 (s, 6 H,
2×CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ = 48.4 (2 C), 64.57, H 8.56; found C 64.52, H 8.48.
46.6 (2 C), 42.4 (2 C), 42.2 (2 C), 38.8 (2 C), 38.7 (2 C), 33.6 (2 C),
{2-[(1R,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-
27.9 (2 C), 23.2 (2 C), 21.9 (2 C) ppm. 77Se NMR (38 MHz, CDCl3,
25 °C): δ = 444.4 ppm. C20H34Se2 (432.40): calcd. C 55.55, H 7.92;
found C 55.01, H 8.21.
ethyl}benzene (22): Purification by column chromatography on sil-
ica gel with petroleum ether/ethyl acetate (95:5). Yield: 330 mg
(79%), yellow oil; dr 62:38. 1H NMR (200 MHz, CDCl3, 25 °C):
3
(+)-Diisobornyl Diselenide (19): Yield: 1.6 g (33%), yellow solid;
major diastereomer: δ = (m, 5 H, Ph), 4.32 (dd, JH,H = 8.0 and
m.p. 170–171 °C. [α]2D0 = +7.04 (c = 7.19, CHCl3). 1H NMR
5.8 Hz, 1 H, CH), 3.24 (s, 3 H, OCH3), 2.95 (dd, 2JH,H = 12.2, 3JH,H
3
2
3
(200 MHz, CDCl3, 25 °C): δ = 3.41 (t, JH,H = 6.4 Hz, 2 H, = 8.0 Hz, 1 H, CH2Se), 2.75 (dd, JH,H = 12.2, JH,H = 5.8 Hz, 1
2×CH), 2.12–1.94 (m, 4 H), 1.81–1.61 (m, 6 H), 1.33–1.11 (m, 4
H, CH2Se), 2.35–2.06 (m, 3 H), 2.80–2.55 (m, 1 H), 1.74–1.64 (m,
3
H), 1.05 (s, 6 H, 2×CH3), 0.92 (s, 6 H, 2×CH3), 0.82 (s, 6 H, 2 H), 1.28–0.95 (m, 4 H), 0.88 (d, JH,H = 7.2 Hz, 3 H, CH3), 0.86
2×CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): δ = 59.3 (2 C), (d, JH,H = 6.2 Hz, 3 H, CH3), 0.72 (d, JH,H = 7.2 Hz, 3 H, CH3)
3
3
3
50.0 (2 C), 47.2 (2 C), 46.5 (2 C), 41.9 (2 C), 38.4 (2 C), 27.4 (2 C),
20.6 (2 C), 19.9 (2 C), 15.6 (2 C) ppm. 77Se NMR (38 MHz, CDCl3,
25 °C): δ = 464.41 ppm. C20H34Se2 (432.40): calcd. C 55.55, H 7.92;
found C 55.52, H 8.14.
ppm; minor diastereomer: δ = 0.74 (d, JH,H = 7.2 Hz, 3 H, CH3)
ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major diastereomer: δ =
141.2, 128.14 (2 C), 127.6, 126.5 (2 C), 84.2, 56.6, 47.5, 44.6, 43.3,
34.5, 33.9, 28.6, 28.4, 24.6, 21.9, 21.2, 14.9 ppm; minor dia-
stereomer: δ = 126.4 (2 C), 84.5, 44.8, 43.5, 34.0 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 230.0 ppm;
minor diastereomer: δ = 227.0 ppm. C19H30OSe (353.40): calcd. C
64.57, H 8.56; found C 64.45, H 8.42.
General Procedure for the Asymmetric Methoxyselenylation: The
diselenide (250 mg, 0.58 mmol) was dissolved in dry dichlorometh-
ane (8 mL) under argon. A 1  solution of bromine (0.58 mL,
0.58 mmol) in tetrachloromethane was added dropwise at –78 °C.
After 15 min, a 0.70  methanol solution of silver triflate (320 mg,
1.80 mL) was added at –78 °C and stirred for another 15 min. The
mixture was treated with the substrate (2.9 mmol) and stirred at
the same temperature for between 2 and 5 h. The reaction was
quenched with aqueous NaHCO3 solution, diluted with 50 mL of
dichloromethane, washed with water and brine, dried, filtered, and
concentrated in vacuo. The crude product was purified by
chromatography on silica gel or basic alumina.
(1R,3S,4R,6S)-3-(Methoxyphenylmethylselanyl)-4,7,7-trimethylbi-
cyclo[4.1.0]heptane (23): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 325 mg
(78%), yellow oil; dr 52:48. 1H NMR (300 MHz, CDCl3, 25 °C):
3
major diastereomer: δ = 7.36 (m, 5 H, Ph), 4.32 (dd, JH,H = 8.4
and 5.4 Hz, 1 H, CH), 3.24 (s, 3 H, OCH3), 3.03 (m, 1 H), 2.95
2
3
2
(dd, JH,H = 12.6, JH,H = 8.4 Hz, 1 H, CH2Se), 2.72 (dd, JH,H
=
3
12.3, JH,H = 5.4 Hz, 1 H, CH2Se), 2.27–2.17 (m, 1 H), 1.84–1.74
(m, 2 H), 1.49–1.38 (m, 1 H), 0.97 (s, 3 H, CH3), 0.91 (d, JH,H
3
=
(1S,2R,5S)-2-(2-Methoxy-2-phenylethylselanylmethyl)-6,6-dimethyl-
bicyclo[3.1.1]heptane (20): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 270 mg
(64%), yellow oil; dr 51:49. 1H NMR (300 MHz, CDCl3, 25 °C):
6.6 Hz, 1 H, CH), 0.85–0.76 (m, 1 H), 0.68–0.50 (m, 2 H) ppm;
minor diastereomer: δ = 3.22 (s, 3 H, OCH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): major diastereomer: δ = 141.3, 128.2 (2
C), 127.7, 126.4 (2 C), 84.4, 56.7, 43.1, 31.3, 30.9, 28.4, 26.1, 25.3,
21.2, 21.1, 20.1, 17.4, 15.7 ppm; minor diastereomer: δ = 84.2, 43.2,
31.6, 25.4, 20.0 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ =
203.7 ppm. C19H28OSe (351.39): calcd. C 64.94, H 8.03; found C
64.90, H 8.01.
3
major diastereomer: δ = 7.34 (m, 5 H, Ph), 4.32 (dd, JH,H = 7.8
2
and 5.4 Hz, 1 H, CH), 3.24 (s, 3 H, OCH3), 2.96 (dd, JH,H = 12.6,
2
3
3JH,H = 7.8 Hz, 1 H, CH2Se), 2.71 (dd, JH,H = 12.6, JH,H
=
5.4 Hz, 1 H, CH2Se), 2.64–2.49 (m, 2 H), 2.36–2.28 (m, 1 H), 2.24–
2.14 (m, 1 H), 2.05–1.78 (m, 4 H), 1.52–1.39 (m, 1 H), 1.18 (s, 3
3
H, CH3), 0.96 (s, 3 H, CH3), 0.86 (d, JH,H = 9.4 Hz, 1 H, CH)
(1R,3R,4R,6S)-3-(Methoxyphenylmethylselanyl)-4,7,7-trimethylbi-
cyclo[4.1.0]heptane (24): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 340 mg
(81%), yellow oil; dr 53:47. 1H NMR (300 MHz, CDCl3, 25 °C):
2
3
ppm; minor diastereomer: δ = 2.95 (dd, JH,H = 12.6, JH,H
=
2
3
7.8 Hz, 1 H, CH2Se), 2.70 (dd, JH,H = 12.6, JH,H = 5.4 Hz, 1 H,
CH2Se), 1.17 (s, 3 H, CH3), 0.97 (s, 3 H, CH3) ppm. 13C NMR
(75 MHz, CDCl3, 25 °C): major diastereomer: δ = 141.2, 128.3 (2
3
major diastereomer: δ = 7.36 (m, 5 H, Ph), 4.32 (dd, JH,H = 8.1
2
C), 127.8, 126.6 (2 C), 84.4, 56.8, 46.1, 41.8, 41.2, 38.5, 33.3, 32.8, and 5.4 Hz, 1 H, CH), 3.24 (s, 3 H, OCH3), 2.94 (dd, JH,H = 12.3,
2
3
31.0, 27.9, 26.0, 23.1, 22.8 ppm; minor diastereomer: δ = 84.3, 46.2,
3JH,H = 8.1 Hz, 1 H, CH2Se), 2.72 (dd, JH,H = 12.3, JH,H
=
41.7, 32.7, 31.1, 22.7 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ 5.4 Hz, 1 H, CH2Se), 2.30–2.20 (m, 1 H), 2.15–2.10 (m, 1 H), 2.01–
3
= 202.7 ppm. C19H28OSe (351.39): calcd. C 64.94, H 8.03; found
C 64.93, H 7.98.
1.87 (m, 2 H), 1.35–1.25 (m, 1 H), 0.97 (d, JH,H = 6.6 Hz, 3 H,
CH3), 0.95 (s, 3 H, CH3), 0.89 (s, 3 H, CH3), 0.57–0.51 (m, 1 H)
ppm; minor diastereomer: δ = 3.23 (s, 3 H, OCH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): major diastereomer: δ = 141.4, 128.2 (2
C), 127.7, 126.5 (2 C), 84.5, 56.7, 44.6, 34.8, 29.8, 29.6, 29.3, 28.7,
21.5, 20.4, 17.2, 15.5 ppm; minor diastereomer: δ = 84.6, 56.6, 44.5,
35.0 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 256.3 ppm; minor diastereomer: δ = 255.7 ppm.
C19H28OSe (351.39): calcd. C 64.94, H 8.03; found C 64.88, H 7.95.
{2-[(1S,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-
ethyl}benzene (21): Purification by column chromatography on sil-
ica gel with petroleum ether/ethyl acetate (95:5). Yield: 350 mg
(86%), yellow oil; dr 70:30. 1H NMR (200 MHz, CDCl3, 25 °C):
3
major diastereomer: δ = 7.34 (m, 5 H, Ph), 4.31 (dd, JH,H = 8.2,
3JH,H = 5.4 Hz, 1 H, CH), 3.36 (m, 1 H, CH), 3.24 (s, 3 H, OCH3),
2
3
2.97 (dd, JH,H = 12.4, JH,H = 8.2 Hz, 1 H, CH2Se), 2.70 (dd,
2JH,H = 12.4, JH,H = 5.4 Hz, 1 H, CH2Se), 2.05–0.98 (m, 9 H),
(1R,2R,3S,5S)-3-(Methoxyphenylmethylselanyl)-2,6,6-trimethylbi-
cyclo[3.1.1]heptane (25): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 200 mg
3
3
3
0.93 (d, JH,H = 6.4 Hz, 3 H, CH3), 0.89 (d, JH,H = 6.4 Hz, 3 H,
CH3), 0.87 (d, 3JH,H = 6.4 Hz, 3 H, CH3) ppm; minor diastereomer:
δ = 3.25 (s, 3 H, OCH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): (48%), yellow oil; dr 52:48. 1H NMR (300 MHz, CDCl3, 25 °C):
3
major diastereomer: δ = 141.5, 128.4 (2 C), 127.9, 126.6 (2 C), 85.0,
major diastereomer: δ = 7.35 (m, 5 H, Ph), 4.38 (dd, JH,H = 7.8
Eur. J. Org. Chem. 2006, 3216–3225
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3221

´
J. Scianowski, Z. Rafin´ski, A. Wojtczak
FULL PAPER
3
and 5.4 Hz, 1 H, CH), 3.65 (q, JH,H = 9.6 Hz, 1 H, CH), 3.25 (s,
25 °C): major diastereomer: δ = 7.44–7.26 (m, 5 H, Ph), 3.10 (s, 3
2
3
2
2
3 H, OCH3), 2.99 (dd, JH,H = 12.3, JH,H = 7.8 Hz, 1 H, CH2Se), H, OCH3), 2.98 (d, JH,H = 11.7 Hz, 1 H, CH2), 2.88 (d, JH,H
=
2.75 (dd, 2JH,H = 12.3, 3JH,H = 5.4 Hz, 1 H, CH2Se), 2.52–1.84 (m, 11.7 Hz, 1 H, CH2), 2.56–2.15 (m, 2 H), 2.04–2.00 (m, 1 H), 1.70
3
7 H), 1.23 (d, JH,H = 9.9 Hz, 1 H, CH), 1.20–1.18 (m, 6 H, CH3),
1.00 (s, 3 H, CH3), 0.99–0.83 (m, 1 H) ppm; minor diastereomer:
(s, 3 H, CH3), 1.66–1.56 (m, 2 H), 1.49–0.95 (m, 5 H), 0.86 (d,
3JH,H = 6.9 Hz, 3 H, CH3), 0.83 (d, JH,H = 6.3 Hz, 3 H, CH3),
3
δ = 3.24 (s, 3 H, OCH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): 0.67 (d, JH,H = 6.9 Hz, 3 H, CH3) ppm; minor diastereomer: δ =
3
3
major diastereomer: δ = 141.4, 128.2 (2 C), 127.9, 126.6 (2 C),
84.4, 56.8, 48.8, 41.9, 39.4, 37.9, 36.2, 34.0, 30.5, 27.8, 27.5, 23.4,
19.5 ppm; minor diastereomer: δ = 84.1, 36.3, 33.8, 30.3, 19.4 ppm.
77Se NMR (38 MHz, CDCl3, 25 °C): δ = 206.4 ppm. C19H28OSe
(351.39): calcd. C 64.94, H 8.03; found C 64.84, H 7.96.
3.11 (s, 3 H, OCH3), 1.70 (s, 3 H, CH3), 0.70 (d, JH,H = 6.9 Hz, 3
H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 143.9, 128.0 (2 C), 127.1, 126.3 (2 C), 79.2, 50.8,
47.7, 44.7, 43.4, 35.3, 34.7, 34.1, 28.7, 24.8, 22.7, 22.1, 21.4,
15.1 ppm; minor diastereomer: δ = 79.3, 47.8, 44.9, 35.8, 34.2, 28.8,
22.9, 15.2 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ =
201.2 ppm. C20H32OSe (367.43): calcd. C 65.37, H 8.78; found C
65.25, H 8.70.
(1R,2R,3R,5S)-3-(Methoxyphenylmethylselanyl)-2,6,6-trimethylbi-
cyclo[3.1.1]heptane (26): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 230 mg
(57%), yellow oil; dr 82:18. 1H NMR (300 MHz, CDCl3, 25 °C):
major diastereomer: δ = 7.35 (m, 5 H, Ph), 4.37 (m, 1 H), 3.25 (s,
3 H, OCH3), 3.10–2.75 (m, 2 H), 2.44–2.29 (m, 2 H), 2.17–1.73 (m,
(1R,3S,4R,6S)-3-(2-Methoxy-2-phenylpropylselanyl)-4,7,7-trimeth-
ylbicyclo[4.1.0]heptane (30): Purification by column chromatog-
raphy on basic alumina with petroleum ether/ethyl acetate (95:5).
Yield: 390 mg (94%), yellow oil; dr 52:48. 1H NMR (300 MHz,
CDCl3, 25 °C): major diastereomer: δ = 7.44–7.22 (m, 5 H, Ph),
3.10 (s, 3 H, OCH3), 3.04–2.62 (m, 3 H), 2.20–1.98 (m, 1 H), 1.84–
1.70 (m, 2 H), 1.69 (s, 3 H, CH3), 1.44–1.28 (m, 1 H), 0.95 (s, 3 H,
CH3), 0.89 (d, JH,H = 6.6 Hz, 3 H, CH3), 0.87 (d, JH,H = 6.6 Hz,
3 H, CH3), 0.85–0.52 (m, 3 H) ppm; minor diastereomer: δ = 3.12
(s, 3 H, OCH3), 0.89 (d, 3JH,H = 6.6 Hz, 3 H, CH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): major diastereomer: δ = 144.0, 127.9 (2
C), 126.9, 126.1 (2 C), 79.1, 50.7, 43.0, 38.2, 30.8, 28.4, 25.8, 25.3,
22.6, 21.5, 21.2, 19.9, 17.3, 15.7 ppm; minor diastereomer: δ =
143.9, 79.0, 43.3, 38.5, 31.0, 26.0, 25.4, 21.3, 20.0 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 181.3 ppm;
minor diastereomer: δ = 180.5 ppm. C20H30OSe (365.41): calcd. C
65.73, H 8.27; found C 65.65, H 8.30.
3
4 H), 1.16 (s, 3 H, CH3), 1.02 (d, JH,H = 7.2 Hz, 3 H, CH3), 0.89
(s, 3 H, CH3) ppm; minor diastereomer: δ = 3.27 (s, 3 H, OCH3)
ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major diastereomer: δ =
141.4, 128.4 (2 C), 127.9, 126.9 (2 C), 84.5, 56.7, 48.4, 45.2, 42.5,
38.6, 38.3, 36.6, 33.8, 29.9, 27.9, 23.1, 21.4 ppm; minor dia-
stereomer: δ = 126.6 (2 C), 45.6, 41.9, 37.0, 30.4 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): δ = 309.5 ppm. C19H28OSe (351.39):
calcd. C 64.94, H 8.03; found C 64.86, H 8.05.
3
3
(1S,2R,5S)-2-(2-Methoxy-2-phenylpropylselanylmethyl)-6,6-dimeth-
ylbicyclo[3.1.1]heptane (27): Purification by column chromatog-
raphy on basic alumina with petroleum ether/ethyl acetate (95:5).
Yield: 210 mg (50%), yellow oil; dr 52:48. 1H NMR (200 MHz,
CDCl3, 25 °C): major diastereomer: δ = 7.38 (m, 5 H, Ph), 3.10 (s,
3 H, OCH3), 3.07–2.81 (m, 2 H), 2.43–1.72 (m, 9 H), 1.69 (s, 3 H,
CH3), 1.50–1.18 (m, 1 H), 1.15 (s, 3 H, CH3), 0.92 (s, 3 H, CH3),
(1R,3R,4R,6S)-3-(2-Methoxy-2-phenylpropylselanyl)-4,7,7-trimeth-
ylbicyclo[4.1.0]heptane (31): Purification by column chromatog-
raphy on basic alumina with petroleum ether/ethyl acetate (95:5).
Yield: 370 mg (89%), yellow oil; dr 52:48. 1H NMR (300 MHz,
CDCl3, 25 °C): major diastereomer: δ = 7.43–7.20 (m, 5 H, Ph),
3
0.82 (d, JH,H = 9.4 Hz, 1 H) ppm; minor diastereomer: δ = 0.90
(s, 3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major
diastereomer: δ = 143.8, 128.0 (2 C), 127.1, 126.3, (2 C), 79.3, 50.8,
46.3, 41.8, 41.2, 38.5, 38.4, 33.3, 33.2, 27.9, 26.0, 23.1, 22.8,
22.5 ppm; minor diastereomer: δ = 144.7, 79.2, 46.2, 41.7, 23.0,
22.7, 22.4 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 115.2 ppm; minor diastereomer: δ = 114.9 ppm.
C20H30OSe (365.41): calcd. C 65.73, H 8.27; found C 65.77, H 8.31.
2
3.10 (s, 3 H, OCH3), 2.96 (d, JH,H = 12.0 Hz, 1 H, CH2), 2.89 (d,
2JH,H = 12.0 Hz, 1 H, CH2), 2.08–1.82 (m, 4 H), 1.69 (s, 3 H, CH3),
3
1.27 (m, 1 H), 0.93 (s, 3 H, CH3), 0.91 (d, JH,H = 6.6 Hz, 3 H,
CH3), 0.85 (s, 3 H, CH3), 0.77–0.64 (m, 2 H), 0.54–0.47 (m, 1 H);
minor diastereomer: δ = 3.10 (s, 3 H, OCH3), 1.68 (s, 3 H, CH3),
0.84 (s, 3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major
diastereomer: δ = 143.9, 128.0 (2 C), 127.1, 126.3 (2 C), 79.3, 50.9,
44.6, 36.6, 34.8, 29.6, 29.3, 28.7, 22.6, 21.6, 20.5, 17.3, 15.5 ppm;
minor diastereomer: δ = 44.9, 37.0, 35.2, 29.5, 22.5 ppm. 77Se
NMR (38 MHz, CDCl3, 25 °C): major diastereomer: δ =
233.7 ppm; minor diastereomer: δ = 231.7 ppm. C20H30OSe
(365.41): calcd. C 65.73, H 8.27; found C 65.61, H 8.15.
[2-[(1S,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-1-
methylethyl]benzene (28): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 140 mg
(33%), yellow oil; dr 62:38. 1H NMR (300 MHz, CDCl3, 25 °C):
major diastereomer: δ = 7.43–7.22 (m, 5 H, Ph), 3.14 (m, 1 H,
2
CHSe), 3.10 (s, 3 H, OCH3), 3.00 (d, JH,H = 11.7 Hz, 1 H, CH2),
2
2.88 (d, JH,H = 11.7 Hz, 1 H, CH2), 1.95–1.75 (m, 2 H), 1.71 (s, 3
3
H, CH3), 1.70–1.50 (m, 3 H), 1.33–0.91 (m, 5 H), 0.90 (d, JH,H
=
3
6.6 Hz, 3 H, CH3), 0.87 (d, JH,H = 6.3 Hz, 3 H, CH3), 0.84 (d,
3JH,H = 6.6 Hz, 3 H, CH3) ppm; minor diastereomer: δ = 3.08 (s,
3 H, OCH3), 1.69 (s, 3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3,
25 °C): major diastereomer: δ = 144.1, 128.1 (2 C), 127.1, 126.3 (2
C), 79.2, 50.8, 49.6, 46.2, 41.9, 38.1, 35.3, 31.0, 27.5, 26.8, 23.0,
22.1, 20.9 ppm; minor diastereomer: δ = 128.4 (2 C), 127.8, 126.4
(2 C), 79.4, 46.4, 38.2, 27.6, 22.8, 20.8 ppm. 77Se NMR (38 MHz,
CDCl3, 25 °C): major diastereomer: δ = 118.4 ppm; minor dia-
stereomer: δ = 120.6 ppm. C20H32OSe (367.43): calcd. C 65.37, H
8.78; found C 65.23, H 8.66.
(1R,2R,3S,5S)-3-(2-Methoxy-2-phenylpropylselanyl)-2,6,6-trimeth-
ylbicyclo[3.1.1]heptane (32): Purification by column chromatog-
raphy on basic alumina with petroleum ether/ethyl acetate (95:5).
Yield: 270 mg (65%), yellow oil; dr 61:39. 1H NMR (300 MHz,
CDCl3, 25 °C): major diastereomer: δ = 7.46–7.22 (m, 5 H, Ph),
2
3.35 (m, 1 H), 3.12 (s, 3 H, OCH3), 3.00 (d, JH,H = 12.0 Hz, 1 H,
2
CH2Se), 2.90 (d, JH,H = 12.0 Hz, 1 H, CH2Se), 2.45–2.08 (m, 3
H), 2.05–1.77 (m, 3 H), 1.73 (s, 3 H, CH3), 1.21–1.11 (m, 6 H,
CH3), 0.94 (s, 3 H, CH3), 0.82 (m, 1 H) ppm; minor diastereomer:
δ = 3.13 (s, 3 H, OCH3), 1.74 (s, 3 H, CH3), 0.95 (s, 3 H, CH3)
[2-[(1R,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-1- ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major diastereomer: δ =
methylethyl]benzene (29): Purification by column chromatography
144.0, 128.1 (2 C), 127.2, 126.3 (2 C), 79.2, 50.9, 48.8, 41.8, 39.4,
37.7, 37.4, 35.8, 33.9, 27.7, 27.5, 23.4, 22.6, 19.5 ppm; minor dia-
on basic alumina with petroleum ether/ethyl acetate (95:5). Yield:
220 mg (55%), yellow oil; dr 72:28. 1H NMR (300 MHz, CDCl3, stereomer: δ = 41.9, 37.8, 36.1, 33.8, 22.7, 19.3 ppm. 77Se NMR
3222
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© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2006, 3216–3225

Optically Active Terpene Dialkyl Diselenides
FULL PAPER
3
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 183.0 ppm;
minor diastereomer: δ = 187.2 ppm. C20H30OSe (365.41): calcd. C
65.73, H 8.27; found C 65.75, H 8.42.
6.9 Hz, 3 H, CH3), 1.25–0.90 (m, 6 H), 0.87 (d, JH,H = 6.9 Hz, 3
3
3
H, CH3), 0.84 (d, JH,H = 6.9 Hz, 3 H, CH3), 0.72 (d, JH,H
=
=
3
6.9 Hz, 3 H, CH3) ppm; minor diastereomer: δ = 4.23 (d, JH,H
5.7 Hz, 1 H, CH), 3.25 (s, 3 H, OCH3), 1.41 (d, 3JH,H = 6.9 Hz, 3 H,
CH3), 0.71 (d, 3JH,H = 6.9 Hz, 3 H, CH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C): major diastereomer: δ = 140.3, 127.9 (2 C), 127.5,
127.2 (2 C), 88.4, 57.3, 48.1, 45.2, 43.3, 39.3, 38.2, 34.7, 34.2, 28.7,
24.9, 22.2, 21.4, 18.2, 15.2 ppm; minor diastereomer: δ = 140.2,
88.2, 45.1, 43.5, 34.0, 28.6, 24.8, 22.1, 21.3, 18.1 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 350.8 ppm;
minor diastereomer: δ = 343.3 ppm. C20H32OSe (367.43): calcd. C
65.37, H 8.78; found C 65.29, H 8.71.
(1R,2R,3R,5S)-3-(2-Methoxy-2-phenylpropylselanyl)-2,6,6-trimeth-
ylbicyclo[3.1.1]heptane (33): Purification by column chromatog-
raphy on basic alumina with petroleum ether/ethyl acetate (95:5).
Yield: 320 mg (76%), yellow oil; dr 66:34. 1H NMR (300 MHz,
CDCl3, 25 °C): major diastereomer: δ = 7.45–7.21 (m, 5 H, Ph),
3.11 (s, 3 H, OCH3), 3.08–2.84 (m, 2 H), 2.51–2.26 (m, 2 H), 2.10–
1.81 (m, 3 H), 1.73 (s, 3 H, CH3), 1.78–1.69 (m, 1 H), 1.39–1.32
3
(m, 1 H), 1.14 (s, 3 H, CH3), 1.04 (d, JH,H = 7.2 Hz, 1 H, CH),
0.94 (d, 3JH,H = 7.2 Hz, 3 H, CH3), 0.82 (s, 3 H, CH3) ppm; minor
diastereomer: δ = 3.12 (s, 3 H, OCH3), 1.71 (s, 3 H, CH3), 1.16
(s, 3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major
diastereomer: δ = 143.8, 128.1 (2 C), 127.2, 126.6 (2 C), 79.5, 51.0,
48.3, 45.0, 42.4, 38.6, 38.1, 36.9, 36.3, 33.7, 27.8, 23.0, 22.4,
21.3 ppm; minor diastereomer: δ = 144.1, 127.1, 126.3 (2 C), 79.1,
50.8, 48.4, 45.6, 38.2, 33.9, 27.9, 23.1, 21.5 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): major diastereomer: δ = 294.7 ppm;
minor diastereomer: δ = 290.0 ppm. C20H30OSe (365.41): calcd. C
65.73, H 8.27; found C 65.65, H 8.18.
(1R,3R,4R,6S)-3-(2-Methoxy-1-methyl-2-phenylethylselanyl)-4,7,7-
trimethylbicyclo[4.1.0]heptane (38): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 340 mg (81%), yellow oil; dr 58:42. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 7.32 (m, 5 H,
Ph), 4.21 (d, 3JH,H = 6.2 Hz, 1 H, CH), 3.23 (s, 3 H, OCH3), 3.15–
3
3.04 (m, 1 H, CH), 2.10–1.80 (m, 4 H), 1.41 (d, JH,H = 7.0 Hz, 3
3
H, CH3), 1.38–1.16 (m, 2 H), 0.95 (d, JH,H = 7.0 Hz, 3 H, CH3),
0.87 (s, 3 H, CH3), 0.81 (s, 3 H, CH3), 0.80–0.43 ppm (m, 2 H);
3
minor diastereomer: δ = 4.23 (d, JH,H = 6.2 Hz, 1 H, CH), 3.26
(1S,2R,5S)-2-(2-Methoxy-1-methyl-2-phenylethylselanylmethyl)-6,6-
dimethylbicyclo[3.1.1]heptane (34): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 363 mg (86%), yellow oil; dr 52:48. 1H NMR
(200 MHz, CDCl3, 25 °C): major diastereomer: δ = 7.36 (m, 5 H,
Ph), 4.24 (d, 3JH,H = 5.8 Hz, 1 H, CH), 3.26 (s, 3 H, OCH3), 3.16–
2.98 (m, 1 H), 2.56–2.42 (m, 2 H), 2.40–2.03 (m, 3 H), 2.02–1.73
(s, 3 H, OCH3), 1.40 (d, 3JH,H = 7.0 Hz, 3 H, CH3) ppm. 13C NMR
(50 MHz, CDCl3, 25 °C): major diastereomer: δ = 140.3, 128.0 (2
C), 127.7, 127.5 (2 C), 88.5, 57.3, 44.6, 40.4, 35.6, 30.3, 29.5, 28.8,
21.7, 20.7, 18.0, 17.4, 15.8 ppm; minor diastereomer: δ = 140.4,
88.4, 57.4, 44.1, 39.5, 18.3, 15.7 ppm. 77Se NMR (38 MHz, CDCl3,
25 °C): major diastereomer: δ = 371.2 ppm; minor diastereomer: δ
= 380.4 ppm. C20H30OSe (365.41): calcd. C 65.73, H 8.27; found
C 65.75, H 8.42.
3
(m, 4 H), 1.49–1.32 (m, 1 H), 1.40 (d, JH,H = 7.0 Hz, 3 H, CH3),
3
1.16 (s, 3 H, CH3), 0.94 (s, 3 H, CH3), 0.84 (d, JH,H = 9.4 Hz, 1
3
H, CH) ppm; minor diastereomer: δ = 4.21 (d, JH,H = 5.8 Hz, 1
(1R,2R,3S,5S)-3-(2-Methoxy-1-methyl-2-phenylethylselanyl)-2,6,6-
trimethylbicyclo[3.1.1]heptane (39): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 250 mg (60%), yellow oil; dr 62:38. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 7.36 (m, 5 H,
Ph), 4.21 (d, 3JH,H = 3.8 Hz, 1 H, CH), 3.27 (s, 3 H, OCH3), 3.29–
3.21 (m, 1 H), 3.15–3.02 (m, 1 H), 2.44–2.24 (m, 2 H), 2.18–2.07
3
H, CH), 3.27 (s, 3 H, OCH3), 1.39 (d, JH,H = 7.0 Hz, 3 H, CH3),
1.15 (s, 3 H, CH3), 0.92 (s, 3 H, CH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C): major diastereomer: δ = 140.0, 127.9 (2 C), 127.5,
127.2 (2 C), 88.0, 57.1, 46.3, 41.9, 41.1, 40.4, 38.4, 33.3, 31.6, 27.9,
26.0, 23.1, 22.8, 17.6 ppm; minor diastereomer: δ = 87.9, 46.2, 41.8,
31.4, 22.7, 17.5 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): major
diastereomer: δ = 246.9 ppm; minor diastereomer: δ = 248.7 ppm.
C20H30OSe (365.41): calcd. C 65.73, H 8.27; found C 65.68, H 8.36.
3
(m, 2 H), 1.94–1.79 (m, 3 H), 1.42 (d, JH,H = 4.8 Hz, 3 H, CH3),
3
1.38–1.26 (m, 1 H), 1.18 (d, JH,H = 7.8 Hz, 3 H, CH3), 1.16–1.14
(m, 1 H), 0.96 (s, 3 H, CH3), 0.85 (m, 1 H) ppm; minor dia-
[2-[(1S,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-
propyl]benzene (35): Purification by column chromatography on ba-
sic alumina with petroleum ether/ethyl acetate (95:5). Yield: 114 mg
3
3
stereomer: δ = 4.27 (d, JH,H = 5.7 Hz, 1 H, CH), 1.43 (d, JH,H
=
6.9 Hz, 3 H, CH3), 0.98 (s, 3 H, CH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C): major diastereomer: δ = 140.4, 127.9 (2 C), 127.5,
127.2 (2 C), 88.2, 57.2, 48.9, 41.9, 39.6, 39.3, 37.9, 35.9, 32.8, 27.7,
27.5, 20.4, 19.9, 17.3 ppm; minor diastereomer: δ = 140.3, 88.1,
41.9, 38.1, 36.6, 27.6, 19.5, 17.8 ppm. 77Se NMR (38 MHz, CDCl3,
25 °C): major diastereomer: δ = 256.4 ppm; minor diastereomer: δ
= 257.6 ppm. C20H30OSe (365.41): calcd. C 65.73, H 8.27; found
C 65.85, H 8.46.
(27%), yellow oil; dr 54:46. 1H NMR (300 MHz, CDCl3, 25 °C):
3
major diastereomer: δ = 7.39–7.24 (m, 5 H, Ph), 4.27 (d, JH,H
=
5.7 Hz, 1 H, CH), 3.27 (s, 3 H, OCH3), 3.06 (m, 1 H), 2.05–1.45
3
(m, 5 H), 1.40 (d, JH,H = 6.9 Hz, 3 H, CH3), 1.35–0.97 (m, 2 H),
3
3
0.91 (d, JH,H = 6.6 Hz, 3 H, CH3), 0.88 (d, JH,H = 6.6 Hz, 3 H,
CH3), 0.83 (d, 3JH,H = 6.3 Hz, 3 H, CH3) ppm; minor diastereomer:
δ = 3.28 (s, 3 H, OCH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C):
major diastereomer: δ = 140.4, 128.1 (2 C), 127.5, 127.3 (2 C), 87.9,
57.4, 49.5, 45.0, 42.2, 42.9, 35.3, 30.8, 27.6, 26.9, 22.2, 21.0, 20.9,
17.9 ppm; minor diastereomer: δ = 140.2, 87.5, 42.7, 40.5, 20.8,
17.8 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): δ = 261.7 ppm;
minor diastereomer: δ = 261.0 ppm. C20H32OSe (367.43): calcd. C
65.37, H 8.78; found C 65.31, H 8.74.
(1S,2R,5S)-2-(2-Methoxy-2-methylcyclopentylselanylmethyl)-6,6-di-
methylbicyclo[3.1.1]heptane (41): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 70 mg (18 %), yellow oil; dr 52:48. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 3.49–3.25 (m,
1 H), 3.23 (s, 3 H, OCH3), 2.71 (m, 1 H), 2.45–2.15 (m, 3 H), 2.10–
1.32 (m, 14 H), 1.31 (s, 3 H, CH3), 1.18 (s, 3 H, CH3), 1.00 (s, 3
[2-[(1R,2S,5R)-2-Isopropyl-5-methylcyclohexylselanyl]-1-methoxy-
propyl]benzene (36): Purification by column chromatography on ba-
sic alumina with petroleum ether/ethyl acetate (95:5). Yield: 260 mg
(62%), yellow oil; dr 52:48. 1H NMR (300 MHz, CDCl3, 25 °C):
major diastereomer: δ = 7.43 (m, 5 H, Ph), 4.28 (d, 3JH,H = 5.7 Hz,
3
H, CH3), 0.88 (d, JH,H = 9.4 Hz, 1 H, CH) ppm; minor dia-
stereomer: δ = 3.22 (s, 3 H, OCH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C) major diastereomer: δ = 85.8, 50.2, 47.4, 46.2, 41.9,
41.2, 38.5, 35.5, 33.3, 32.4, 32.1, 27.8, 26.0, 23.0, 22.8, 21.2,
1 H, CH), 3.26 (s, 3 H, OCH3), 3.18–3.09 (m, 1 H), 2.55–2.16 (m, 20.4 ppm; minor diastereomer: δ = 47.2, 41.8, 35.8, 22.7 ppm. 77Se
3
2 H), 2.06–1.87 (m, 1 H), 1.71–1.52 (m, 4 H), 1.42 (d, JH,H
=
NMR (38 MHz, CDCl3, 25 °C): major diastereomer: δ =
Eur. J. Org. Chem. 2006, 3216–3225
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3223

´
J. Scianowski, Z. Rafin´ski, A. Wojtczak
FULL PAPER
184.7 ppm; minor diastereomer: δ = 186.2 ppm. C17H30OSe
δ = 312.0 ppm; minor diastereomer: δ = 308.1 ppm. C17H30OSe
(329.38): calcd. C 61.98, H 9.18; found C 61.92, H 9.14.
(329.38): calcd. C 61.98, H 9.18; found C 62.00, H 9.15.
(1S,2S,4R)-1-Isopropyl-2-(2-methoxy-2-methylcyclopentylselanyl)-4-
methylcyclohexane (42): Purification by column chromatography on
silica gel with petroleum ether/ethyl acetate (95:5). Yield: 140 mg
(33%), yellow oil; dr 78:22. 1H NMR (300 MHz, CDCl3, 25 °C):
major diastereomer: δ = 3.43 (m, 1 H, CHSe), 3.24 (s, 3 H, OCH3),
2.36–1.36 (m, 14 H), 1.34 (s, 3 H, CH3), 1.31–1.02 (m, 2 H), 0.94
(d, 3JH,H = 6.6 Hz, 3 H, CH3), 0.89 (d, 3JH,H = 6.6 Hz, 3 H, CH3),
(1R,2R,3S,5S)-3-(2-Methoxy-2-methylcyclopentylselanyl)-2,6,6-tri-
methylbicyclo[3.1.1]heptane (46): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 121 mg (32%), yellow oil; dr 70:30. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 3.85 (m, 1 H),
3.52–3.25 (m, 1 H), 3.24 (s, 3 H, OCH3), 2.55–2.04 (m, 5 H), 1.96–
3
1.60 (m, 8 H), 1.32 (s, 3 H, CH3), 1.20 (d, JH,H = 7.8 Hz, 3 H,
3
0.88 (d, JH,H = 6.6 Hz, 3 H, CH3) ppm; minor diastereomer: δ =
CH3), 1.17 (s, 3 H, CH3), 1.00 (s, 3 H, CH3) ppm; minor dia-
3.22 (s, 3 H, OCH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C):
major diastereomer: δ = 85.6, 50.2, 49.5, 47.0, 44.9, 41.9, 35.8, 35.4,
32.9, 31.0, 27.6, 26.9, 22.2, 21.4, 20.9, 20.8 ppm; minor dia-
stereomer: δ = 85.7, 49.6, 47.1, 45.0, 42.4, 31.1 ppm. 77Se NMR
(38 MHz, CDCl3, 25 °C): δ = 292.2 ppm. C17H32OSe (331.40):
calcd. C 61.60, H 9.73; found C 61.58, H 9.74.
3
stereomer: δ = 1.30 (s, 3 H, CH3), 1.17 (d, JH,H = 7.8 Hz, 3 H,
CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 85.9, 50.4, 49.0, 46.2, 42.0, 39.6, 38.2, 36.5, 36.0,
33.2, 32.6, 27.9, 27.6, 23.6, 21.5, 20.7, 19.9 ppm; minor dia-
stereomer: δ = 85.7, 48.8, 41.9, 36.4, 32.5, 27.5, 21.4, 20.6 ppm.
77Se NMR (38 MHz, CDCl3, 25 °C): major diastereomer: δ =
263.1 ppm. C17H30OSe (329.38): calcd. C 61.98, H 9.18; found C
61.90, H 9.19.
(1S,2R,4R)-1-Isopropyl-2-(2-methoxy-2-methylcyclopentylselanyl)-
4-methylcyclohexane (43): Purification by column chromatography
on silica gel with petroleum ether/ethyl acetate (95:5). Yield: 380 mg
(84%), yellow oil; dr 75:25. 1H NMR (300 MHz, CDCl3, 25 °C):
major diastereomer: δ = 3.23 (s, 3 H, OCH3), 2.93–2.67 (m, 1 H),
2.43–2.17 (m, 3 H), 1.83–1.59 (m, 8 H), 1.31 (s, 3 H, CH3), 1.30–
(1R,2R,3R,5S)-3-(2-Methoxy-2-methylcyclopentylselanyl)-2,6,6-tri-
methylbicyclo[3.1.1]heptane (47): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 180 mg (44%), yellow oil; dr 72:28. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 3.42–3.25 (m,
1 H), 3.24 (s, 3 H, OCH3), 3.22–3.10 (m, 1 H), 2.64–2.52 (m, 1 H),
2.41–2.18 (m, 2 H), 2.10–1.89 (m, 3 H), 1.82–1.60 (m, 6 H), 1.32
3
1.15 (m, 3 H), 1.11–0.90 (m, 2 H), 0.89 (d, JH,H = 6.9 Hz, 3 H,
3
3
CH3), 0.88 (d, JH,H = 6.0 Hz, 3 H, CH3), 0.76 (d, JH,H = 6.9 Hz,
3 H, CH3) ppm; minor diastereomer: δ = 3.25 (s, 3 H, OCH3), 1.29
(s, 3 H, CH3), 0.73 (d, JH,H = 6.9 Hz, 3 H, CH3) ppm. 13C NMR
3
3
(s, 3 H, CH3), 1.18 (s, 3 H, CH3), 1.13 (d, JH,H = 7.2 Hz, 3 H,
3
(50 MHz, CDCl3, 25 °C): major diastereomer: δ = 86.0, 50.3, 48.1,
45.7, 45.6, 43.8, 35.3, 34.8, 34.3, 33.2, 28.9, 25.0, 22.2, 21.5, 21.3,
20.7, 15.2 ppm; minor diastereomer: δ = 85.6, 47.7, 45.4, 33.4, 28.7,
20.8, 15.0 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 205.1 ppm; minor diastereomer: δ = 206.3 ppm.
C17H32OSe (331.40): calcd. C 61.60, H 9.73; found C 61.52, H 9.67.
CH3), 1.04 (d, JH,H = 9.6 Hz, 1 H, CH), 1.01 (s, 3 H, CH3) ppm;
minor diastereomer: δ = 1.30 (s, 3 H, CH3), 1.11 (d, 3JH,H = 7.2 Hz,
3 H, CH3) ppm. 13C NMR (50 MHz, CDCl3, 25 °C): major dia-
stereomer: δ = 86.1, 50.4, 48.5, 47.0, 45.8, 42.6, 39.2, 38.6, 36.8,
35.6, 34.0, 33.1, 27.9, 23.2, 21.5, 21.3, 20.6 ppm; minor dia-
stereomer: δ = 85.7, 49.9, 45.5, 38.9, 35.9, 33.2, 21.2, 20.8 ppm.
77Se NMR (38 MHz, CDCl3, 25 °C): δ = 372.1 ppm.C17H30OSe
(329.38): calcd. C 61.98, H 9.18; found C 62.11, H 9.29.
(1R,3S,4R,6S)-3-(2-Methoxy-2-methylcyclopentylselanyl)-4,7,7-tri-
methylbicyclo[4.1.0]heptane (44): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 70 mg (18 %), yellow oil; dr 65:35. 1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 3.24 (s, 3 H,
OCH3), 3.22–3.15 (m, 1 H), 2.42–2.15 (m, 2 H), 1.92–1.62 (m, 7
H), 1.54–1.32 (m, 2 H), 1.30 (s, 3 H, CH3), 0.98 (s, 3 H, CH3), 0.97
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3297–3304; f) M. Tiecco, L. Testaferri, F. Marini, S. Sternativo,
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3
(s, 3 H, CH3), 0.94 (d, JH,H = 6.9 Hz, 3 H, CH3), 0.90–0.53 (m, 3
H) ppm; minor diastereomer: δ = 3.22 (s, 3 H, OCH3) ppm. 13C
NMR (50 MHz, CDCl3, 25 °C): major diastereomer: δ = 85.7, 50.3,
47.4, 42.4, 35.7, 32.7, 30.8, 28.5, 26.2, 25.7, 21.9, 21.3, 20.9, 20.7,
21.1, 17.5, 15.8 ppm; minor diastereomer: δ = 85.9, 47.5, 42.5, 35.6,
32.6, 30.7, 28.4, 21.8 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C):
major diastereomer: δ = 320.2 ppm; minor diastereomer: δ =
324.6 ppm. C17H30OSe (329.38): calcd. C 61.98, H 9.18; found C
62.02, H 9.20.
(1R,3R,4R,6S)-3-(2-Methoxy-2-methylcyclopentylselanyl)-4,7,7-tri-
methylbicyclo[4.1.0]heptane (45): Purification by column
chromatography on basic alumina with petroleum ether/ethyl ace-
tate (95:5). Yield: 125 mg (33 %), yellow oil; dr 70:30.1H NMR
(300 MHz, CDCl3, 25 °C): major diastereomer: δ = 3.31 (m, 1 H),
3.23 (s, 3 H, OCH3), 2.53–2.44 (m, 1 H), 2.28–1.94 (m, 5 H), 1.84–
1.60 (m, 7 H), 1.40–1.31 (m, 1 H), 1.29 (s, 3 H, CH3), 1.02 (d, 3JH,H
= 6.6 Hz, 3 H, CH3), 0.95 (s, 3 H, CH3), 0.87–0.70 (m, 2 H), 0.61–
0.54 (m, 1 H) ppm; minor diastereomer: δ = 3.21 (s, 3 H, OCH3),
1.28 (s, 3 H, CH3), 0.94 (s, 3 H, CH3) ppm. 13C NMR (50 MHz,
CDCl3, 25 °C): major diastereomer: δ = 86.0, 50.3, 46.5, 45.9, 44.1,
35.6, 35.1, 32.5, 30.1, 29.5, 28.8, 21.7, 21.4, 20.7, 20.6, 17.4,
15.4 ppm; minor diastereomer: δ = 85.9, 46.4, 44.0, 35.0, 21.6,
15.3 ppm. 77Se NMR (38 MHz, CDCl3, 25 °C) major diastereomer:
3224
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Eur. J. Org. Chem. 2006, 3216–3225

Optically Active Terpene Dialkyl Diselenides
FULL PAPER
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´
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the orthorhombic space group P212121. The X-ray data were
collected at 293(2) K with an Oxford Sapphire CCD dif-
fractometer, graphite monochromator, Mo-Kα radiation (λ =
0.71073 Å), cell parameters a = 6.3470(10), b = 11.660(2), c =
29.011(6) Å, V = 2147.0(7) Å3, Dcalc 1.350 Mgm–3, Z = 4,
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matrix least-squares on F2 with the use of SHELX-97[13] to R1
= 0.0778, wR2 = 0.1541 for [I Ͼ 2σ(I)] reflections. The absolute
structure was determined by the Flack method,[14] x = 0.10(3).
Non-hydrogen atoms were refined anisotropically and hydro-
gen atoms were constrained as riding atoms. The (S,S,R)
(C1,C2,C5) chirality is identical in both neomenthyl moieties.
CCDC-267154 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
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Received: January 19, 2006
Published Online: May 22, 2006
Eur. J. Org. Chem. 2006, 3216–3225
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3225