DTBB-catalysed lithiation of 1,2-bis(phenylsulfanyl)ethene: Does 1-lithio-2-phenylsulfanylethene really exist?

Article abstract of DOI:10.1016/j.tet.2005.07.056

The reaction of (Z)- or (E)-1,2-bis(phenylsulfanyl)ethene (1) with an excess of lithium and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 2.5 mol%) in the presence of a carbonyl compound as electrophile (Barbier conditions) in THF at -78°C leads, after hydrolysis with water at temperatures ranging between -78°C and rt, to a mixture of the corresponding (Z/E)-unsaturated 1,4-diols 2, the diastereomers ratio being independent of the stereochemistry of the starting materials. Allylic alcohols 3 are the main by-products, resulting from a lithium-hydrogen exchange on some of the lithiated intermediates along the whole process. A mechanistic explanation for the observed behaviour is given.

Full text of DOI:10.1016/j.tet.2005.07.056

Tetrahedron 61 (2005) 9325–9330
DTBB-catalysed lithiation of 1,2-bis(phenylsulfanyl)ethene:
does 1-lithio-2-phenylsulfanylethene really exist?
*
´ ´
Cecilia Gomez, Beatriz Macia and Miguel Yus
´ ´ ´ ´
Departamento de Quımica Organica, Facultad de Ciencias and Instituto de Sıntesis Organica (ISO), Universidad de Alicante, Apdo. 99,
03080 Alicante, Spain
Received 7 June 2005; revised 15 July 2005; accepted 18 July 2005
Available online 9 August 2005
Abstract—The reaction of (Z)- or (E)-1,2-bis(phenylsulfanyl)ethene (1) with an excess of lithium and a catalytic amount of 4,40-di-tert-
butylbiphenyl (DTBB, 2.5 mol%) in the presence of a carbonyl compound as electrophile (Barbier conditions) in THF at K78 8C leads, after
hydrolysis with water at temperatures ranging between K78 8C and rt, to a mixture of the corresponding (Z/E)-unsaturated 1,4-diols 2, the
diastereomers ratio being independent of the stereochemistry of the starting materials. Allylic alcohols 3 are the main by-products, resulting
from a lithium–hydrogen exchange on some of the lithiated intermediates along the whole process. A mechanistic explanation for the
observed behaviour is given.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
coordination by the oxygen atom exerting an important
stabilising effect.9 In the case of nitrogen-containing
intermediates of type III, the corresponding (Z)-derivatives
VIII have been prepared by direct deprotonation10 or by
bromine–lithium exchange,11 only one example of an (E)-
derivative IX having been described so far, to the best of our
knowledge.12 However, as far as we know, only two
examples of sulfur-containing derivatives of type III have
been reported in the literature, the dilithium compound X
(prepared by double tin–lithium exchange from the
corresponding stannathiacyclopentene)13 and XI (generated
by direct deprotonation).14 On the other hand, dilithium
intermediates of the type XII (not accessible from the
corresponding dihalo compounds) are interesting reagents
in synthetic organic chemistry because in the reaction with
electrophiles they are able to introduce two electrophilic
fragments in one only synthetic operation (Chart 1).15 In this
paper we want to report the arene-catalysed lithiation16–18 of
1,2-bis(phenylsulfanyl)ethenes with the aim of generating
dilithium intermediates of type XII, involving mono-
lithiated species of type III with XZPhS. This last
intermediate has not only the drawback of decomposing
by b-elimination (the PhSK is a good leaving group), but
also it can deprotonate intra or intermolecularly a carbon–
hydrogen bond at the a-position with respect to the sulfur
atom (for instance in the starting materials).
Among functionalised organolithium compounds,1 the
corresponding sp3-hybridised b-substituted derivatives I
are extremely unstable even at very low temperature, so
they decompose very easily by b-elimination giving an
olefin.2 There are two main ways to stabilise intermediates
of type I: (a) locating a negative charge at the heteroatom
(as in II) in order to inhibit the ability of the group YK to act
as a leaving one,3 and (b) bonding the lithium atom to a sp2-
hybridised carbon atom (as in III), which can stabilise better
the negative charge. Concerning the heteroatom, only
oxygen- or nitrogen-containing intermediates of type II
and III have been reported so far. For instance, chloro-
vinyllithiums (IV) were generated with essentially 0% yield
even at very low temperatures.3 For oxygen-containing
derivatives, while (Z)-ethoxyvinyllithium (V) can be
generated at low temperature by bromine–lithium4 or tin–
lithium exchange,5 the corresponding (E)-analogue decom-
poses easily (even at K50 8C) to give acetylene.6 As
expected, the stability of this type of intermediates is
increased notably when an anionic group is located at the
b-position (such as in intermediate VI, prepared by
bromine–lithium exchange)7 or when a chelating hetero-
atom is in an adequate position (such as in compound VII,
generated by direct deprotonation),8 in the last case the
Keywords: DTBB-catalysed lithiation; Sulfur–lithium exchange; Dilithium
synthons; Unsaturated 1,4-diols.
2. Results and discussion
*
Corresponding author. Tel.: C34 965 903548; fax: C34 965 903549;
e-mail: yus@ua.es
The reaction of (Z)-1,2-bis(phenylsulfanyl)ethene [(Z)-1
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.07.056

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C. Gomez et al. / Tetrahedron 61 (2005) 9325–9330
9326
Chart 1.
Scheme 1. Reagents and conditions: (i) Li, DTBB (cat.), R2COZEt2CO, nPr2CO, (n-C5H11)2CO, iPr2CO, (CH2)5CO, THF, K78 8C; (ii) H2O, K78 8C to rt.
(96:4)] with an excess of lithium (1:7 mol ratio; theoretical
1:4 mol ratio) and a catalytic amount of 4,40-di-tert-
butylbiphenyl (DTBB; 1:0.1 mol ratio; 2.5% mol) in the
presence of a ketone as electrophile (1:3 mol ratio) in THF
at K78 8C gave, after hydrolysis with water, the
corresponding diols 2 as a (Z/E)-mixture of diastereomers
with low to modest isolated yields (Scheme 1, Chart 2 and
Table 1, entries 1–5). In general, the main by-product in the
crude reaction mixture was the corresponding allylic
alcohols 3.
independently of the starting material. Two important
problems are associated to intermediates XIII: (a) the (E)-
diastereomer suffers easy b-elimination to yield acetylene,
even at low temperature,4a and (b) a lithium–hydrogen
exchange can take place from intermediates XIII giving
either phenyl vinyl thioether (abstracting a proton from the
reaction medium, probably from THF21) or a new
intermediate XVII (by intra or intermolecular deprotona-
tion). Anyhow, once intermediates XIII have survived, they
react with a carbonyl compound also with retention to yield
alkoxides XIV, which suffer again a sulfur–lithium
exchange to give the corresponding organolithium inter-
mediates XV with the same stereochemistry. This type of
intermediates are configurationally stable22 and do not
undergo equilibration, so the corresponding final products
XVI arise from the reaction of compounds XV with the
same electrophile present in the reaction medium with
retention of the configuration. Final hydrolysis of these
dialkoxides XVI gives the expected diols 2. Another
important problem with dianions of type XV is their
instability by abstracting a proton from the reaction medium
to give the most abundant by-products, the allylic alcohols 3
through the corresponding alkoxides XVIII (Chart 3). As
can be seen, from the former considerations, it is easy to
explain the low yields obtained in the lithiation of
compounds 1 and in situ reaction with carbonyl compounds.
As can be seen in Scheme 1, one important aspect
concerning the stereochemistry has to do with the final
proportion of (Z/E)-diastereomers depending on the geo-
metry of the starting material 1. Thus, starting from an
enriched material (Z)-1 (96:4) or (E)-1 (89:11) and
3-pentanone, the same (Z/E)-ratio was observed in both
cases: 0.47/1 (Table 1, entries 1 and 6). The same behaviour
was observed with cyclohexanone, so a 0.67/1 (Z/E)-ratio
was obtained for both starting materials (Table 1, entries 5
and 7). These results clearly indicate that some equilibration
takes place through the whole reaction. Initially a sulfur–
lithium exchange occurs, which in principle works with
retention of the configuration,19 but once intermediates XIII
are formed an equilibrium can take place,20 so the
corresponding mixture of diastereomers is obtained
Chart 2.

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C. Gomez et al. / Tetrahedron 61 (2005) 9325–9330
9327
Table 1. Preparation of compounds 2
Entry
Starting
materiala
Electrophile
R2CO
Productb
No.
Conversion (%)
GC yield (%)c
Isolated yield
(%)d
Z/E Ratioe
1
2
3
4
5
6
7
(Z)-1
(Z)-1
(Z)-1
(Z)-1
(Z)-1
(E)-1
(E)-1
Et2CO
nPr2CO
(n-C5H11)2CO
iPr2CO
(CH2)5CO
Et2CO
(CH2)5CO
2a
2b
2c
2d
2e
2a
2e
O99
O99
O99
O99
O99
O99
O99
36 (55)
33 (—f)
36 (25)
25 (—f)
30 (43)
17 (48)
32 (52)
30
30
35
15
20
15
18
0.47/1
0.56/1
0.76/1
0.10/1
0.67/1
0.47/1
0.67/1
a Purity of (Z)-1: Z/E ratio 96/4. Purity of (E)-1: E/Z ratio 89/11.
1
b All products 2 were O95% pure (GLC and/or 300 MHz H NMR).
c In parenthesis estimated yield of the monocondensation alcohol 3.
d Isolated yield of analytically pure compounds 2 after flash chromatography (neutral silica gel, hexane/ethyl acetate) based on the starting material 1.
1
e Deduced from the crude reaction mixture by 300 MHz H NMR.
f
Not determined.
Due to the difficulty of assigning the stereochemistry of
products 2 by spectroscopic means, we separated both
diastereomers, looking for the possibility of performing a
X-ray determination. That was the case for the major
diastereomer (E)-2e (Fig. 1). Knowing the geometry of both
(Z)- and (E)-2, we conclude that in all cases the olefinic
protons in (E)-diastereomers appear at lower field than for
the corresponding (Z)-ones.
phenylthiolate under ethanol reflux as a mixture of (Z/E)-
diastereomers, which was separated by flash chromato-
graphy to yield both enriched (Z)- and (E)-1.23
Pure diols (Z)- and (E)-2e were treated separately under
acidic conditions (H3PO4 85%) in order to study the
corresponding possible dehydration, the results being
different depending on the structure of the starting diol.
Thus, as expected, compound (Z)-2e yielded the heterocycle
4e in quantitative yield (O95%), while its (E)-isomer gave a
mixture of olefinic compounds resulting from a dehydration
process. This result suggests that no (E)/(Z) isomerization
occurred under the assayed acidic reaction conditions.
Starting materials 1 were prepared from commercially
available (Z)-1,2-dichloroethene by reaction with potassium
3. Conclusion
In conclusion, from the results described here, we propose
that there is an equilibrium between both (Z)- and (E)-
intermediates of type XIII, so the same ratio of (Z/E)-
products 2 is obtained starting from differently enriched
(Z/E)-mixtures of disulfides 1. Even working with poor
yields (due to the high instability of intermediates XIII and
XV) the reaction allows the introduction of two electrophilic
fragments at both carbon atoms of ethylene so, in this way,
compounds 1 act as synthetic equivalents of the unknown
ethene 1,2-dianion (see, for instance, intermediate XII). By-
products 3 are not interesting from a synthetic point of view,
because they can be easily prepared by addition of a vinyl
Chart 3.
Figure 1.

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C. Gomez et al. / Tetrahedron 61 (2005) 9325–9330
9328
metal (for example, commercially available vinyl-
magnesium bromide) to a ketone.
desired compounds. Solid products were recrystallized in
hexane/diethyl ether. Yields are given in Table 1; physical,
analytical spectroscopic data as well as literature references
for the known compounds follow. Some by-products 3
(3a,c,d) were characterized by GLC-MS from the crude
reaction mixture, the corresponding data (tr and MS) as well
as literature references also follow.
4. Experimental
4.1. General
4.3.1. (Z)-3,6-Diethyl-4-octene-3,6-diol [(Z)-2a].26 White
solid. Mp 73 8C; trZ11.1 min; Rf (hexane/ethyl acetate
8:2)Z0.2; n (KBr) 3364, 3053, 975, 736 cmK1; dH 0.92
(12H, t, JZ7.5 Hz, 4!CH3), 1.60, 1.61 (8H, 2q, JZ7.5 Hz,
4!CH2), 5.28 (2H, s, HC]CH); dC 8.3 (CH3), 34.4 (CH2),
76.1 (COH), 135.1 (HC]CH); m/z 182 (MCKH2O, 2%),
171 (12), 154 (11), 153 (100), 57 (24); HRMS: MCKC2H5,
found 171.1389. C10H19O2 requires 171.1385.
For general information see Ref. 24. Lithium powder was
prepared from commercially available lithium granules
(99%, high sodium content, Aldrich) as it was already
reported by us.25 X-ray analysis was performed at the
Technical Services of the University of Alicante, the
corresponding details being given below.
4.2. Preparation of (Z)-and (E)-1,2-bis(phenylsulfanyl)-
1-ethene [(Z)- and (E)-1]23
4.3.2. (E)-3,6-Diethyl-4-octene-3,6-diol [(E)-2a].26 White
solid. Mp 66 8C; trZ10.9 min; Rf (hexane/ethyl acetate
(Z)-1,2-Dichloroethene (3 mL, 38.5 mmol) was added, with
stirring, to a solution of potassium hydroxide (9.05 g,
137 mmol) and thiophenol (8.3 mL, 81 mmol) in ethanol
(120 mL). The mixture was refluxed at 80 8C for 7 h, the
solvent was then evaporated (15 Torr) and the resulting
residue was diluted with water and extracted with ethyl
acetate. The organic layer was dried over anhydrous MgSO4
and evaporated (15 Torr) to give the desired mixture of (Z)-
and (E)-diastereomers (80:20), which was separated by flash
chromatography (neutral silica gel, hexane) to yield both
enriched (Z) and (E)-1.
8:2)Z0.1; n (KBr) 3603, 3467 (OH), 3010, 908, 734 cmK1
;
dH 0.87 (12H, t, JZ7.5 Hz, 4!CH3), 1.55, 1.57 (8H, 2q,
JZ7.5 Hz, 4!CH2), 5.56 (2H, s, HC]CH); dC 7.9 (CH3),
33.4 (CH2), 75.6 (COH), 133.7 (HC]CH); m/z 182 (MCK
H2O, 2%), 172 (11), 171 (100), 153 (66), 135 (11), 125 (12),
107 (16), 97 (24), 93 (10), 85 (16), 83 (16), 81 (11), 69 (20),
57 (87), 55 (34); HRMS: MC, found 171.1387. C12H24O2
requires 171.1385.
4.3.3. (Z)-4,7-Dipropyl-5-decene-4,7-diol [(Z)-2b].26
White solid. Mp 66–70 8C; trZ13.4 min; Rf (hexane/ethyl
acetate 8:2)Z0.4; n (KBr) 3384, 908, 735 cmK1; dH 0.91
(12H, t, JZ7.3 Hz, 4!CH3), 1.26–1.56 (16H, m, 8!CH2),
4.19 (2H, br s, 2!OH), 5.26 (2H, s, HC]CH); dC 14.5
(CH3), 17.2 (CH2CH3), 44.8 (CH2COH), 75.7 (COH), 135.0
(HC]CH); m/z 238 (MCKH2O, 1%), 196 (14), 195 (100),
71 (12); HRMS: MCKC3H7, found 213.1843. C13H25O2
requires 213.1855.
4.2.1. (Z)-1,2-Bis(phenylsulfanyl)-1-ethene [(Z)-1].23
Yellow liquid. trZ17.0 min; Rf (hexane)Z0.2; n (film)
3056, 3043, 928, 736, 687 cmK1; dH 6.51 (2H, s, HC]CH),
7.21–7.42 (10H, m, ArH); dC 125.3, 126.9, 129.2, 129.4,
134.9; m/z 244 (MC, 100%), 199 (10), 135 (67), 134 (54),
121 (11), 109 (28), 91 (33), 77 (11), 65 (13); HRMS: MC,
found 244.0370. C14H12S2 requires 244.0380.
4.2.2. (E)-1,2- Bis(phenylsulfanyl)-1-ethene [(E)-1].23
White solid. Mp 63 8C; trZ17.5 min; Rf (hexane)Z0.1; n
(KBr) 3061, 3059, 908, 733, 690 cmK1; dH 6.49 (2H, s,
HC]CH), 7.18–7.39 (10H, m, ArH); dC 124.8, 126.7,
129.0, 129.2, 135.0; m/z 244 (MC, 100%), 199 (10), 135
(60), 134 (47), 109 (23), 91 (27), 65 (11); HRMS: MC,
found 244.0393. C14H12S2 requires 244.0380.
4.3.4. (E)-4,7-Dipropyl-5-decene-4,7-diol [(E)-2b].26
White solid. Mp 57–62 8C; trZ13.2 min; Rf (hexane/ethyl
acetate 8:2)Z0.3; n (KBr) 3404, 3054, 975, 745 cmK1; dH
0.90 (12H, t, JZ7.3 Hz, 4!CH3), 1.26–1.52 (16H, m, 8!
CH2), 5.58 (2H, s, HC]CH); dC 14.5 (CH3), 16.8
(CH2CH3), 43.7 (CH2COH), 75.2 (COH), 133.7
(HC]CH); m/z 238 (MCKH2O, 1%), 214 (14), 213
(100), 195 (37), 99 (13), 83 (15), 71 (50), 69 (22), 57
(11), 55 (12); HRMS: MCKC3H7, found 213.1846.
C13H25O2 requires 213.1855
4.3. DTBB-catalysed lithiation of (Z) and (E)-1,2-
bis(phenylsulfanyl)ethene [(Z) and (E)-1] and in situ
reaction with carbonyl compounds. Preparation of
compounds 2
4.3.5. (Z)-6,9-Dipentyl-7-tetradecene-6,9-diol [(Z)-2c].26
White solid. Mp 78 8C; trZ17.6 min; Rf (hexane/ethyl
acetate 8:2)Z0.3; n (KBr) 3383, 910, 740 cmK1; dH 0.88
(12H, t, JZ6.8 Hz, 4!CH3), 1.23–1.33, 1.51–1.58 (32H,
m, 16!CH2), 5.26 (2H, s, HC]CH); dC 12.4 (CH3), 21.0,
22.0, 30.7, 40.8 (CH2), 74.1 (COH), 133.5 (HC]CH); m/z
350 (MCKH2O, 1%), 280 (21), 279 (100); HRMS: MCK
C5H11, found 297.2787. C19H37O2 requires 297.2794.
To a cooled green suspension of lithium (49 mg, 7 mmol)
and DTBB (26 mg, 0.1 mmol) in THF (2 mL) at K78 8C
was slowly added a solution of the corresponding
electrophile (3 mmol) and (Z) or (E)-1,2-bis(phenyl-
sulfanyl)ethene (244 mg, 1 mmol) in THF (3 mL). The
resulting mixture was stirred for 3 h at the same temperature
and then it was hydrolysed with water (5 mL) allowing the
temperature to rise to 20 8C. The resulting mixture was
extracted with ethyl acetate (3!10 mL). The organic layer
was dried over anhydrous MgSO4 and evaporated (15 Torr).
The resulting residue was then purified by flash chroma-
tography (neutral silica gel, hexane/ethyl acetate) to give the
4.3.6. (E)-6,9-Dipentyl-7-tetradecene-6,9-diol [(E)-2c].26
White solid. Mp 70 8C; trZ17.5 min; Rf (hexane/ethyl
acetate 8:2)Z0.2; n (KBr) 3512, 3199, 908, 734 cmK1; dH
0.88 (12H, t, JZ6.6 Hz, 4!CH3), 1.21–1.34, 1.43–1.59
(32H, m, 16!CH2), 5.56 (2H, s, HC]CH); dC 14.0 (CH3),

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C. Gomez et al. / Tetrahedron 61 (2005) 9325–9330
9329
22.6, 23.3, 32.3, 41.5 (CH2), 75.3 (COH), 133.8 (HC]CH);
m/z 350 (MCKH2O, 1%), 298 (21), 297 (100), 279 (27), 99
(15), 71 (17); HRMS: MCKC5H11, found 297.2787.
C19H37O2 requires 297.2794.
in toluene (3 mL) was added H3PO4 85% (2 drops). The
mixture was stirred for 2 h at room temperature, dried over
anhydrous MgSO4 and evaporated (1 Torr). The resulting
residue was then purified by flash chromatography (neutral
silica gel, hexane/ethyl acetate). Yield is given in the text
and physical, analytical and spectroscopic data follow.
4.3.7. (Z)-3,6-Diisopropyl-2,7-dimethyl-4-octene-3,6-diol
[(Z)-2d].27 White solid. Mp 80 8C; trZ13.4 min; Rf
(hexane/ethyl acetate 8:2)Z0.2; n (KBr) 3554, 909,
738 cmK1; dH 0.88, 0.92 (24H, 2d, JZ6.7 Hz, 8!CH3),
1.90–1.98 (4H, m, 4!CH), 5.29 (2H, s, HC]CH); dC 16.9,
17.6 (CH3), 33.7 (CH), 76.9, 80.2 (COH), 129.0 (HC]CH);
m/z 238 (MCKH2O, 1%), 214 (14), 213 (100), 195 (15),
127 (14), 109 (13), 97 (13), 71 (51), 69 (20); HRMS: MCK
C3H7, found 213.1851. C13H25O2 requires 213.1855.
4.4.1. 7-Oxadispiro[5.1.5.2.]pentadec-14-ene (4e). Yellow
liquid. trZ11.1 min; Rf (hexane/ethyl acetate 8:2)Z0.5; n
(film) 3025, 1651, 1075 cmK1; dH 0.83–1.71 (20H, m, 10!
CH2), 5.86 (2H, s, HC]CH); dC 22.7, 23.6, 39.6 (CH2),
88.3 (COH), 132.3 (HC]CH); m/z 206 (MC, 21%), 164
(13), 163 (100), 135 (11), 107 (34), 94 (11); HRMS: MC,
found 206.1669. C14H22O requires 206.1671.
4.3.8. (E)-3,6-Diisopropyl-2,7-dimethyl-4-octene-3,6-diol
[(E)-2d].27 White solid. Mp 62 8C. trZ13.5 min; Rf
(hexane/ethyl acetate 8:2)Z0.1; n (KBr) 3484, 918,
745 cmK1; dH 0.86, 0.90 (24H, 2d, JZ6.7 Hz, 8!CH3),
1.90–1.99 (4H, m, 4!CH), 5.51 (2H, s, HC]CH); dC 16.5,
17.7 (CH3), 33.5 (CH), 77.2, 79.6 (COH), 132.0 (HC]CH);
m/z 238 (MCKH2O, 1%), 213 (16), 196 (14), 195 (100),
153 (29), 71 (21); HRMS: MCKC3H7, found 213.1846
C13H25O2 requires 213.1855.
4.5. X-ray analysis
Crystal data (deposited at the Cambridge Crystallographic
Data Centre: CCDC 274485): C14H24O2, MZ224.33;
˚
˚
triclinic, aZ9.7410(16) A, bZ19.424(3) A, cZ23.917(4)
˚
˚
A, aZ68.0698, bZ86.1798, gZ87.8588; VZ6194.4(19)
3
A ; space group P(1; ZZ12; DcZ1.067 Mg mK3; lZ
ꢀ
0.71073 A; mZ0.069 mmK1; F(000)Z1488; TZ297G
˚
1 8C. Data collection was performed on a Bruker Smart
´
CCD diffractometer in ‘Servicios Tecnicos de Investiga-
cion’ of University of Alicante, based on three u-scan runs
4.3.9. 1-[(Z)-2-(1-Hydroxycyclohexyl)-1-ethenyl]-1-
cyclohexanol [(Z)-2e].27 White solid. Mp 145 8C; trZ
14.3 min; Rf (hexane/ethyl acetate 8:2)Z0.2; n (KBr) 3603,
3467 (OH), 3010, 908, 734 cmK1; dH 1.28–1.88 (20H, m,
10!CH2), 3.88 (2H, br s, 2!OH), 5.40 (2H, s, HC]CH);
dC 22.0, 25.4, 39.2 (CH2), 72.0 (COH), 135.9 (HC]CH);
m/z 224 (MC, 12%), 206 (13), 164 (13), 163 (100), 149 (16),
145 (11), 135 (15), 107 (36), 95 (12), 91 (12), 81 (13), 79
(14), 67 (10), 55 (14); HRMS: MC, found 224.1777.
C14H24O2 requires 224.1776.
´
(starting uZK348) at values fZ08, 1208, 2408 with the
detector at 2qZK328. An additional run of 100 frames, at
2qZK328, uZK348 and fZ08, was acquired to improve
redundancy. For each of these runs, 606 frames were
collected at 0.38 intervals and 30 s per frame. The diffraction
frames were integrated using the program SAINT.29 The
structure was solved by direct methods29 and refined to all
13242 unique F2o by full matrix least squares.30 All of the
hydrogen atoms were placed at idealised positions and
refined as rigid atoms. Final wR2Z0.1588 for all data and
878 parameters; R1Z0.0697 for 3025 FoO4s(Fo).
4.3.10. 1-[(E)-2-(1-Hydroxycyclohexyl)-1-ethenyl]-1-
cyclohexanol [(E)-2e].27 White solid. Mp 117 8C; trZ
14.2 min; Rf (hexane/ethyl acetate 8:2)Z0.1; n (KBr) 3603,
3467 (OH), 3010, 908, 734 cmK1; dH 1.26–1.67 (20H, m,
10!CH2), 5.81 (2H, s, HC]CH); dC 22.1, 25.5, 38.1
(CH2), 71.3 (COH), 135.1 (HC]CH); m/z 224 (MC, 8%),
206 (20), 188 (17), 181 (62), 163 (27), 153 (13), 149 (11),
145 (35), 135 (18), 131 (16), 126 (13), 125 (100), 117 (10),
112 (36), 111 (27), 110 (14), 109 (13), 107 (26), 99 (21), 98
(14), 97 (28), 96 (25), 95 (24), 94 (13), 93 (20), 91 (23), 83
(23), 82 (14), 81 (40), 79 (29), 77 (14), 71 (11), 69 (17), 67
(27), 55 (47); HRMS: MC, found 224.1790. C14H24O2
requires 224.1776.
Acknowledgements
´
This work was generously supported by the Direccion
General de Ensen˜anza Superior (DGES) of the current
´
Spanish Ministerio de Educacion y Ciencia (MEC; grant no.
CTQ2004-01261) and the Generalitat Valenciana (grant no.
GRUPOS03/135). We also thank Dr. R. Chinchilla for
carrying out the PM3 calculations and MEDALCHEMY
S.L. for a gift of chemicals. B. M. thanks the MEC for a
predoctoral fellowship.
4.3.11. 3-Ethyl-1-penten-3-ol (3a).28 trZ4.5 min; m/z 114
(MC, 3%), 96 (10), 87 (16), 85 (100), 58 (27), 57 (10).
References and notes
4.3.12. 3-Pentyl-1-octen-3-ol (3c). trZ10.3 min; m/z 198
(MC, 1%), 128 (10), 127 (100), 67 (11), 57 (19), 55 (12).
´
1. For reviews, see: (a) Najera, C.; Yus, M. Trends Org. Chem.
´
4.3.13. 1-Vinylcyclohexanol (3e).27 trZ6.2 min; m/z 126
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1991, 2, 155. (b) Najera, C.; Yus, M. Org. Prep. Proc. Int.
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To a solution of the corresponding diol (0.1 mmol, 22 mg)

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