γ-Lactones as templates in ring-closing metathesis: Enantioselective synthesis of medium sized carbocycles fused to butyrolactones

Article abstract of DOI:10.1016/j.jorganchem.2006.08.021

A methodology for accessing enantiomerically enriched carbocyclic systems fused to γ-lactones is described. Key steps are the stereoselective synthesis of highly substituted γ-lactones and ring-closing metathesis of the suitable ramifications. The process permits the choice of stereochemistry, regioselectivity and ring size of the fused compounds.

Full text of DOI:10.1016/j.jorganchem.2006.08.021

Journal of Organometallic Chemistry 691 (2006) 5326–5335
www.elsevier.com/locate/jorganchem
c-Lactones as templates in ring-closing metathesis:
Enantioselective synthesis of medium sized carbocycles
fused to butyrolactones
a
*
´
´
´
´
Jose Luis Ravelo, Carmen M Rodrıguez, Vıctor S. Martın
Instituto Universitario de Bio-Orga´nica ‘‘Antonio Gonza´lez’’, Universidad de La Laguna, C/Astrofı´sico Francisco Sa´nchez,
2, 38206 La Laguna, Tenerife, Spain
Received 30 June 2006; received in revised form 14 August 2006; accepted 14 August 2006
Available online 22 August 2006
Abstract
A methodology for accessing enantiomerically enriched carbocyclic systems fused to c-lactones is described. Key steps are the ster-
eoselective synthesis of highly substituted c-lactones and ring-closing metathesis of the suitable ramifications. The process permits the
choice of stereochemistry, regioselectivity and ring size of the fused compounds.
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: c-Lactone; RCM; Carbocycles; Stereoselective synthesis
1. Introduction
tionalized dienes has been extensively utilized in the synthe-
sis of various organic frameworks [11].
c-Lactones are widely distributed in nature in many bio-
logically important natural products [1]. This structural
unit also plays a very important role in the synthesis of bio-
logically active natural products [2]. In addition, the c-lac-
tone unit is often found fused to medium-sized rings [3].
Included among these structures are the ambrosin (1) [4],
vernolepin (2) [5], elephantopin (3) [6] and Corey lactone
(4) [2a]. Approaches to the stereocontrolled synthesis of
such complex system are highly desirable [7] (Fig. 1).
The base-induced cyclization of enantiomerically
enriched a-[(phenylthio)acyloxy]-a,b-unsaturated esters 7
produces highly substituted butyrolactones 8 with a high
degree of stereocontrol (Scheme 1) [8]. After oxidation,
the alkylation of the anion generated a to the lactone car-
bonyl of these a-benzenesulfonyl c-lactones proceeded with
excellent diastereoselection [9]. On the other hand, ring-
closing metathesis (RCM) [10] reaction of densely func-
Guided by this set of construction reactions, we pon-
dered a general methodology to the stereoselective access
to carbocyclic systems fused to a c-lactone ring (9, and
11) based on the retrosynthetic simplification outlined in
Scheme 2. In both a,b- or b,c-fused systems the cyclic dou-
ble bond could arise via RCM of the suitable diene system
(10 and 12). Both molecules should be available either by
diastereoselective alkylation or proper homologation of
the stereochemically defined butyrolactone 8. This method-
ology could ensure stereochemistry, ring size of the fused
system and divergence from a common intermediate [12]
(see Scheme 2).
2. Results and discussion
Based on the retrosynthetic analysis presented above,
the first critical issue on the way to testing the RCM strat-
egy for the synthesis of carbocyclic fused system was the
enantioselective construction of the polysubstituted
butyrolactone 14. In general, the basic sequence outlined
in Scheme 1 was followed to access the necessary c-lactone.
*
Corresponding author. Tel./fax: +34 922318579.
´
E-mail address: vmartin@ull.es (V.S. Martın).
0022-328X/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.08.021

J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
5327
O
O
OH
O
O
O
O
O
H
O
O
H
AcO
O
O
O
O
O
OMe
O
1
2
3
4
O
Fig. 1. Representative structures featuring a fused carbocycle to a butyrolactone.
O
PhSCH2COOH
Encumbered
-face
O
SPh
O
R1
OH
6
Ti(OPr- ) , CH Cl
i
4
2
2
5
R1
OH
R1
S
O
O
OH
O
Na
O
O
1. NaIO4, MeOH/H2O
O
NaH, DMF
SPh
Preferential
attack
SPh
CO2Me
O
R
O
2. (MeO)2P(O)CH2CO2Me
NaH, Benzene
R1
CO2Me
R4-X
R1
8
7
Fig. 2. Stereochemical model for the alkylation of a-benzenesulfonyl-c-
a, R1 = C H - ,
7 n
3
lactones.
, R1 = (CH2)2OTBDPS,
, R1 = (CH2)3OTBDPS,
b
c
Scheme 1.
O
13
,
O
SO2Ph
R4
SO Ph
1. NaOH, THF/H2O
2. BH3·SMe2, THF
1. NaH, DMF
2. R4Br
2
8a
O
O
R1
®
R1
3. Oxone , MeOH/H2O
OH
OH
O
O
14 (a-d)
R2
R2
RCM
RCM
( )m
( )m
∗
O
O
R3
∗
R3
∗
∗
, R1 = C H - , R4 = CH2CH=CH2
7 n
a
∗
∗
3
R1
R1
( )n
( )n
1. SO3·Py, CH2Cl2
b, R1 = C H - , R4 = (CH2)2CH=CH2
7 n
3
10 (a-d)
2 = SO2Ph
, R1 = C H - , R4 = (CH2)3CH=CH2
7 n
c
9
10
3
R
, R1 = C H - , R4 = CH2C(CH3)=CH2
d
7 n
2. Ph3PCH3Br,
KHDMS, THF
3
8
O
O
∗
∗
∗
R2
R2
Scheme 3.
O
∗
O
∗
∗
( )m ( )n
( )m ( )n
coordination of the sodium cation with one oxygen of the
sulfone group and the oxygen of the enolate causes the
anti-p-face of the enolate relative to the b-substituent to
be encumbered by the phenyl group of the phenylsulfone,
directing the alkylating agents to the syn face (Fig. 2) [9].
Oxidation of the primary alcohol 14 and Wittig reaction
provided the necessary diene system 10 for the ring-closing
metathesis step (Scheme 3).
Having reached these advanced intermediates, we tested
the ring-closing olefin metathesis reaction. Exposure of the
dienes 10 to second generation Grubbs’ catalyst 15 pro-
vided the corresponding a,b-fused unsaturated cycles 9 in
good to high yield depending of the ring size (Table 1)
[15]. The coupling between geminal disubstituted olefins
with terminal alkenes provided the corresponding trisubti-
tuted cyclic alkene also in good yield (entry 4).
11
12
Scheme 2.
It should be pointed out that in order to homologate the R1
substituent it must contain a suitable functional group at
this end. In our case a tert-butyl diphenyl silyl ether was
adequate for this propose. Known epoxides 5 [13], were
submitted to our previously reported sequence [8] yielding
satisfactorily the common intermediate 8. At this point of
the synthesis, two alternative ways were followed depend-
ing if a,b- or b,c-fused systems are the desired target.
The synthesis of the diene 10 needs stereoselective alkyl-
ation at the a-carbon of the lactone system and proper
functional group manipulation on the ester functionality.
In order to accomplish both tasks, 8a was saponified to
the corresponding carboxylic acid that was reduced to the
primary alcohol and the sulfide group was oxidated to
the sulfone 13. The base-induced alkylation with a series
of unsaturated alkylating agents proceeded chemo- and ste-
reoselectively yielding the contrasteric product 14 [14]. The
As mentioned earlier, the synthesis of the alternative
diene 12 from the common c-lactone 8 needed the neces-
sary manipulation of the functional group at the R1 and
the ester substituents. Thus, proceeding with the synthesis,
the above mentioned sequence of saponification of the ester
functionality, reduction to primary alcohol, oxidation and

5328
J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
Table 1
4. Experimental
Stereoselective synthesis of a,b-fused unsaturated cycles to c-lactones
4.1. General remarks
N
N
Mes
Cl
Cl
Mes
Ph
1H and 13C NMR spectra were recorded at 25 °C on a
Bruker Avance-400 and/or 300 spectrometer in CDCl3 as
solvent, and chemical shifts are reported relative to Me4Si.
Low- and high-resolution mass spectra were taken using a
Micromass Autospec spectrometer. Elemental analyses
were performed on a Fisons Instruments EA 1108
CHNS-O. Optical rotations were determined for solutions
in chloroform or n-hexane with a Perkin–Elmer Model 241
polarimeter. Column chromatography was performed on
O
O
SO2Ph
( )m
Ru
PCy3
SO2Ph
( )m
15
O
O
R3
R3
R1
CH2Cl2, 40 ˚C
R1
9 (a-d)
10 (a-d)
Entry
10
Yield (9)
1
2
3
4
10a, R3 = H, m = 1
10b, R3 = H, m = 2
10c, R3 = H, m = 3
10d, R3 = Me, m = 1
85
85
45
85
˚
Merck silica gel, 60 A and 0.2–0.5 mm. Visualization of
spots was performed with UV light and/or phosphomolyb-
dic acid in ethanol stain. All solvents were purified by stan-
dard techniques [16]. Reactions requiring anhydrous
conditions were performed under argon. Anhydrous mag-
nesium sulfate was used for drying solutions.
Wittig homologation provided the suitable terminal alkene
16. To fulfill the diene system the silyl protecting group was
readily removed and an almost identical sequence of oxida-
tion and Wittig reaction was performed yielding 12 (n = 1,
R2 = SPh), regardless of the carbon chain length. Again,
these intermediates were submitted to carbene 15 affording
the corresponding b,c-unsaturated fused c-lactones 11b
and 11c in excellent yields as the only detected products
(Scheme 4).
4.2. General procedure to obtain 3-(phenylthio)acyloxy 1,2-
diols from enantiomerically enriched 2,3-epoxy alcohols
4.2.1. Preparation of (2S,3R)-1,2-dihydroxyhexan-3-yl 2-
(phenylthio)acetate (6a)
To a stirred solution of (2S, 3S)-epoxy-1-hexanol [13]
(5 g, 0.043 mol) in dry CH2Cl2 (430 mL) was added (phenyl-
thio)acetic acid (10.9 g, 0.065 mol) at 0 °C under argon. The
mixture was stirred for 15 min, and Ti(OPr-i)4 (15.4 mL,
0.052 mol) was added. After the addition, the mixture was
allowed to warm to room temperature and the solution
was stirred for 2 h. A solution of aqueous tartaric acid
(15% w/v, 400 mL) was added, and this final mixture was
stirred until clear phases were reached (30 min). The phases
were separated and the aqueous phase was extracted with
CH2Cl2. The combined organic phases were washed with
a saturated aqueous solution of NaHCO3 and brine, dried,
concentrated, and purified by column chromatography, to
3. Conclusions
We have shown that the conjunction of our protocol for
accessing to highly substituted c-lactones and ring-closing
metathesis provides a suitable methodology to enantio-
meric unsaturated carbocyclic systems fused to c-lactones.
In addition to the high stereochemical control in all substi-
tuent in the butyrolactone system and control in the ring
size, we synthesize systems with enough functional groups
to elaborate more complicated molecules, such us the gen-
eration of a-methylene c-lactones [8], butenolides [8] and
series of structures resulting of manipulation of the gener-
ated cyclic alkene [12]. Applications of the reported strat-
egy to the synthesis of bioactive natural compounds are
subject of study in our laboratory and well be reported in
due course.
25
yield 6a (11.51 g, 94% yield) as an oil: ½aꢀD ¼ þ11:1 (c
1
1.32, CHCl3); H NMR (CDCl3) d 0,85 (t, J = 7.21 Hz,
3H), 1.28 (m, 2H), 1.57 (m, 2H), 3.12 (br s, 1H), 3.45 (br
s, 1H), 3.56 (m, 3H), 3.66 (s, 2H), 4.88 (m, 1H), 7.25 (m,
O
O
1. NaOH, THF/H2O
1. -Bu NF, THF
n
SPh
SPh
8
(b,c)
4
O
O
2. BH3·SMe2, THF
3. SO3·Py, CH2Cl2
4. Ph3PCH3Br,
2. SO3·Py, CH2Cl2
R1
( )m
3. Ph3PCH3Br,
KHDMS, THF
16
12
, R1 = (CH2)2OTBDPS
, R1 = (CH2)3OTBDPS
, m = 1
KHDMS, THF
16b
16c
12b
12c, m = 2
O
O
O
SPh
SPh
15
15
O
12b
12c
CH2Cl2, 40
(85 %)
CH2Cl2, 40
(89 %)
11b
11c
Scheme 4.

J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
5329
2H), 7.39 (m, 3H); 13C NMR (CDCl3) d 13.8 (q), 18.4 (t),
32.3 (t), 36.7 (t), 62.6 (t), 72.8 (d), 75.7 (d), 127.1 (d),
129.1 (d), 129.9 (d), 134.8 (s), 170.1 (s); MS m/z (relative
intensity) 284 (M)+ (25), 253 (2), 168 (61), 123 (100); HRMS
Calc. for C14H20O4S (M)+ 284.1082, found 284.1078.
(500 mL), and washed with a saturated aqueous solution of
NaHCO3 (200 mL) and brine (200 mL), dried over MgSO4,
filtered and concentrated, and purified by column chroma-
tography, to give 7a (7.92 g, 73% yield) as an oil:
25
1
½aꢀD ¼ þ19; 9 (c 1.24, CHCl3); H NMR (CDCl3) d 0.84
(t, J = 7.19 Hz, 3H), 1.24 (m, 2H), 1.57 (m, 2H), 3.64 (s,
2H), 3.69 (s, 3H), 5.37 (m, 1H), 5.90 (dd, J = 15.7,
1.5 Hz, 1H), 6.77 (dd, J = 15.7, 5.3 Hz, 1H), 7.24 (m,
2H), 7.38 (m, 3H); 13C NMR (CDCl3) d 13.3 (q), 17.70
(t), 35.4 (t), 36.3 (t), 51.2 (q), 73.0 (d), 121.1 (d), 126.7
(d), 128.7 (d), 129.8 (d), 134.4 (s), 144.71 (d), 165.9 (s),
166.4 (s); MS m/z (relative intensity) 308 (M)+ (18), 168
(6), 141 (54), 123 (100); HRMS Calc. for C16H20O4S
(M)+ 308.1082, found 308.1093.
4.2.2. Preparation of (2S,3R)-1,2-dihydroxy-5-tert-butyldi-
phenylsilyloxy-pentan-3-yl-2-(phenylthio)-acetate (6b)
Prepared from (2S,3S)-epoxy-5-tert-butyldiphenylsilyl-
oxy-1-pentanol [13] (4.16 g, 11.7 mmol) to give 6b (4.9 g,
25
80% yield) as an oil: ½aꢀD ¼ ꢁ2:85 (c 1.44, CHCl3); 1H
NMR (CDCl3) d 1,05 (s, 9H), 1.89 (m, 2H), 2.09 (br s,
1H), 3.21 (br s, 1H), 3.45 (dd, J = 11.8, 5.4 Hz, 1H), 3.56
(s, 2H), 3.62 (m, 1H), 3.69 (m, 3H), 5.05 (m, 1H), 7.38
(m, 9H), 7.63 (m, 6H); 13C NMR (CDCl3) d 19.0 (s), 26.7
(q), 33.2 (t), 36.6 (t), 59.9 (t), 62.6 (t), 72.5 (d), 73.1 (d),
127.1 (d), 127.7 (d), 129.1 (d), 129.8 (d), 133.1 (s), 135.5
(d), 169.7 (s); MS m/z (relative intensity) 449 (M ꢁ 75)+
(3), 269 (16), 199 (100), 123 (64); HRMS Calc. for
C25H25O4SiS (M ꢁ 75)+ 449.1243, found 449.1251.
4.3.2. Preparation of methyl (4R)-4-[(phenylthio)-acet-
oxy]-6-tert-butyldiphenylsilyloxy-hexen-2(E)-oate (7b)
Prepared from 6b (4.5 g, 8.58 mmol) to give 7b (3.57 g,
25
1
76% yield) as an oil: ½aꢀD ¼ þ10; 97 (c 1.44, CHCl3); H
NMR (CDCl3) d 1,04 (s, 9H), 1.86 (m, 2H), 3.58 (s, 2H),
3.66 (m, 2H), 3.72 (s, 3H), 5.64 (m, 1H), 5.92 (dd,
J = 15.7, 1.4 Hz, 1H), 6.81 (dd, J = 15.7, 5.4 Hz, 1H),
7.39 (m, 9H), 7.62 (m, 6H); 13C NMR (CDCl3) d 18.9 (s),
26.5 (q), 36.3 (t), 36.4 (t), 51.4 (q), 59.0 (t), 70.7 (d),
121.2 (d), 127.5 (d), 129.5 (d), 133.2 (s), 135.3 (d), 144.8
(d), 166.2 (s), 168.4 (s); MS m/z (relative intensity) 491
(M ꢁ 57)+ (27), 413 (2), 349 (68), 199 (93); HRMS Calc.
for C27H27O5SiS (M ꢁ 57)+ 491.1348, found 491.1354.
4.2.3. Preparation of (2S,3R)-1,2-dihydroxy-6-tert-butyldi-
phenylsilyloxy-hexan-3-yl-2-(phenylthio)acetate (6c)
Prepared from 6-tert-butyldiphenylsilyloxy-hexen-2(E)-
ol [13] (3.65 g, 9.86 mmol) to give 6c (4.3 g, 81% yield) as
25
1
an oil: ½aꢀD ¼ þ0:91 (c 4.39, CHCl3); H NMR (CDCl3)
d 1,08 (s, 9H), 1.58 (m, 4H), 2.9 (br s, 1H), 3.48 (dd,
J = 11.9, 5.9 Hz, 1H), 3.62 (m, 2H), 3.65 (s, 2H), 3.69 (m,
2H), 4.92 (m, 1H), 7.42 (m, 9H), 7.69 (m, 6H); 13C NMR
(CDCl3) d 18.9 (s), 26.3 (t), 26.6 (q), 27.8 (t), 36.2 (t),
62.1 (t), 63.0 (t), 72.3 (d), 75.3 (d), 126.8 (d), 127.4 (d),
128.8 (d), 129.3 (d), 129.6 (d), 133.5 (s), 134.3 (s), 135.2
(d), 169.8 (s); MS m/z (relative intensity) 463 (M ꢁ 75)+
(15), 349 (37), 235 (43), 199 (100); HRMS Calc. for
C26H27O4SiS (M ꢁ 75)+ 463.3029, found 463.3035.
4.3.3. Preparation of methyl (4R)-4-[(phenylthio)-acet-
oxy]-7-tert-butyldiphenylsilyloxy-hepten-2(E)-oate (7c)
Prepared from 6c (4 g, 7.43 mmol) to give 7c (3.09 g,
25
74% yield) as an oil: ½aꢀD ¼ þ4:87 (c 2.3, CHCl3); 1H
NMR (CDCl3) d 1,04 (s, 9H), 1.50 (m, 2H), 1.72 (m,
2H), 3.60 (m, 2H), 3.67 (s, 2H), 3.75 (s, 3H), 5.40 (m,
1H), 5.90 (dd, J = 15.7, 0.9 Hz, 1H), 6.78 (dd, J = 15.7,
5.2 Hz, 1H), 7.40 (m, 9H), 7.63 (m, 6H); 13C NMR
(CDCl3) d 19.2 (s), 26.8 (q), 27.7 (t), 30.1 (t), 36.7 (t),
51.7 (q), 63.1 (t), 73.4 (d), 121.6 (d), 127.6 (d), 129.1 (d),
133.7 (s), 135.5 (d), 144.9 (d), 166.3 (s), 168.8 (s); MS m/z
(relative intensity) 505 (M ꢁ 57)+ (29), 349 (100), 213
(31), 199 (63); HRMS Calc. for C28H29O5SiS (M ꢁ 57)+
505.1505, found 505.1505.
4.3. General procedure to transform 3-(phenylthio)acyloxy-
1,2-diols into c-(phenylthio)acyloxy-a,b-unsaturated esters
4.3.1. Preparation of methyl (4R)-4-[(phenylthio)-acet-
oxy]hepte-2(E)-enoate (7a)
To a stirred solution of 6a (10 g, 0.035 mol) in MeOH/
H2O (20:1, 70 mL) were added NaIO4 (18.83 g,
0.088 mol) and a catalytic amount of tetrabutylammonium
periodate at room temperature. After 1 h, the mixture was
filtered through a pad of celite and washed with ether. The
resulting solution was concentrated, yielding an oil of the
crude aldehyde, which was used without purification.
To a suspension of sodium hydride (1.9 g, 0.063 mol,
80% in mineral oil) in benzene (500 mL), at 0 °C was added
slowly (trimethylphosphono)acetate (11.34 mL, 0.070 mol)
in benzene (50 mL). After complete addition the mixture
was stirred for 5 min and the crude aldehyde dissolved in
benzene (150 mL) was added dropwise. The reaction mix-
ture was stirred for 30 min, after which time TLC showed
complete conversion to the unsaturated ester. The reaction
was quenched with acetic acid (4 mL), extracted with ether
4.4. General cyclization procedure of c-(phenylthio)acyloxy
a,b-unsaturated esters
4.4.1. Preparation of methyl 2-((2R,3R,4S)-5-oxo-4-(phe-
nylthio)-2-propyl-tetrahydrofuran-3-yl)acetate (8a)
To a suspension of sodium hydride (1.43 g, 0.036 mmol,
80% in mineral oil) in dry DMF (162 mL) under argon at
ꢁ50 °C was added dropwise the unsaturated ester 7a
(10 g, 0.032 mmol) in dry DMF (162 mL). The reaction
mixture was stirred for 4 h, after which time TLC showed
complete conversion into the lactone. The reaction was
quenched with acetic acid (4 mL) and extracted with ether.
The combined organic phases were washed with a saturated

5330
J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
aqueous solution of NaHCO3 and brine, dried and concen-
trated. Purification by silica gel column chromatography
reaction was extracted in AcOEt. The combined organic
phases were washed with a saturated aqueous solution of
brine, dried and concentrated. Purification by column
chromatography yielded (2R,3R,4S)-[5-oxo-4-(phenyl-
thio)-2-propyltetrahydrofuran-3- yl]acetic acid (7.9 g, 92%
25
gave 8a (9.5 g, 95% yield) as an oil: ½aꢀD ¼ þ7:1 (c 11.4,
1
CHCl3); H NMR (CDCl3) d 0.86 (t, J = 7.05 Hz, 3H),
1.35 (m, 4H), 2.40 (m, 1H), 2.56 (d, J = 5.8, Hz, 2H), 3.68
(s, 3H), 3.75 (d, J = 10.3, Hz, 1H), 4.22 (m, 1H), 7.32 (m,
3H), 7,55 (m, 2H); 13C NMR (300 MHz, CDCl3) d 13.6
(q), 18.4 (t), 34.7 (t), 36.0 (t), 43.1 (d), 51.3 (d), 51.8 (q),
82.2 (d), 128.7 (d), 129.2 (d), 131.5 (s), 134.1 (d), 171.0 (s),
173.5 (s); MS m/z (relative intensity) 308 (M)+ (86), 277
(3), 249 (7), 168 (32), 109 (96); HRMS Calc. for
C16H20O4S (M)+ 308.1082, found 308.1083.
25
yield) as an oil: ½aꢀD ¼ þ2:3 (c 2.7, CHCl3); 1H NMR
(CDCl3) d 0.87 (t, J = 7.1 Hz, 3H), 1.41 (m, 2H), 1.56
(m, 2H), 2.39 (m, 1H), 2.66 (d, J = 5.9 Hz, 2H), 3.75 (d,
J = 10.2 Hz, 1H), 4,20 (m, 1H), 7.32 (m, 3H), 7.55 (m,
2H), 10.98 (br s, 1H); 13C NMR (CDCl3) d 13.7 (q), 18.5
(t), 34.3 (t), 35.4 (t), 42.7 (d), 51.2 (d), 82.2 (d), 129.0 (d),
129.3 (d), 131.1 (s), 134.4 (d), 173.7 (s), 175.9 (s); MS m/z
(relative intensity) 294 (M)+ (100), 168 (29), 149 (21), 110
(68); HRMS Calc. for C15H18O4S (M)+ 294.0926, found
294.0938. Anal. Calc. for C15H18O4S: C, 61.22, H, 6.45,
S, 10.56. Found: C, 61.20, H, 6.16, S, 10.89.
4.4.2. Preparation of methyl 2-(2R,3R,4S)-5-oxo-4-(phe-
nylthio)-2-(2-tert-butyldiphenylsilyloxy)ethyl-tetrahydrofu-
ran-3-yl-acetate (8b)
Prepared from 7b (3.4 g, 6.2 mmol) to give 8b (3.23 g,
To a stirred solution of (2R,3R,4S)-[5-oxo-4-(phenyl-
25
1
95% yield) as an oil: ½aꢀD ¼ þ12; 75 (c 2.51, CHCl3); H
NMR (CDCl3) d 1,03 (s, 9H), 1.83 (m, 2H), 2.43
(m,1H), 2.63 (d, J = 5.9 Hz, 2H), 3.69 (s, 3H), 3.81 (d,
J = 7.6 Hz, 1H), 4.47 (m, 1H), 7.31 (m, 3H), 7.41 (m,
6H), 7.56 (m, 2H), 7.62 (m, 4H); 13C NMR (CDCl3) d
18.9 (s), 26.6 (q), 34.1 (t), 36.9 (t), 43.0 (q), 50.9 (d),
51.7 (d), 59.4 (t), 78.9 (d), 127.5 (d), 128.6 (d), 129.0
(d), 129.5 (d), 131.1 (s), 133.1 (s), 133.9 (d), 135.2(d),
170.8 (s), 173.4 (s); MS m/z (relative intensity) 491
(M ꢁ 57)+ (10), 255 (100), 199 (81); HRMS Calc. for
C27H27O5SiS (M ꢁ 57)+ 491.1348, found 491.1344.
thio)-2-propyltetrahydrofuran-3-yl]acetic
acid
(7.5 g,
0.025 mol) in dry THF (127 mL, 0.2 M) under argon
was added dropwise the complex BH3 Æ SMe2 (2 M) in
THF (15.3 mL, 0.031 mol) at ꢁ10 °C. The mixture was
allowed to warm slowly to room temperature and stirred
additionally for 6–8 h until TLC showed the end of the
reaction. Then the mixture was cooled to 0 °C and
quenched by careful addition of MeOH (10.3 mL,
0.25 mol). The resulting solution was evaporated in
vacuo and the obtained crude was purified by column
chromatography to give (3S,4R,5R)-4-(2-hydroxyethyl)-
3-phenylthio-5-propyldihydrofuran-2-one (6.28 g, 88%
25
4.4.3. Preparation of methyl 2-(2R,3R,4S)-5-oxo-4-(phe-
nylthio)-2-(3-tert-butyldiphenylsilyloxy)propyl-tetrahydro-
furan-3-yl-acetate (8c)
yield) as an oil: ½aꢀD ¼ þ28:4 (c 0.38, CHCl3); 1H
NMR (CDCl3) d 0.89 (t, J = 7.0 Hz, 3H), 1.43 (m,
2H), 1.59 (m, 2H), 1.84 (m, 2H), 2.18 (m, 1H), 2.55
(br s, 1H), 3.59 (d, J = 10.1 Hz, 1H), 3.85 (m, 2H),
4.09 (m, 1H), 7.34 (m, 3H), 7.59 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.7 (t), 36.4 (t), 43.6 (d), 52.3 (d),
60.0 (t), 83.3 (d), 128.8 (d), 129.3 (d), 131.7 (s), 133.9
(d), 174.6 (s); MS m/z (relative intensity) 280 (M)+
(100), 262 (47), 149 (12), 110 (82); HRMS Calc. for
C15H20O3S (M)+ 280.1133, found 280.1131. Anal. Calc.
for C15H20O3S: C, 64.26, H, 7.19, S, 11.44. Found: C,
64.27, H, 7.47, S, 11.29.
Prepared from 7c (2.8 g, 4.98 mmol) to give 8c (2.66 g,
25
95% yield) as an oil: ½aꢀD ¼ þ5:07 (c 2.6, CHCl3); 1H
NMR (CDCl3) d 1,04 (s, 9H), 1.55 (m, 2H), 1.68
(m,2H), 2.39 (m, 1H), 2.60 (d, J = 6.1 Hz, 2H), 3.63 (m,
2H), 3.69 (s, 3H), 3.76 (d, J = 10.2 Hz, 1H), 4.20 (ddd,
J = 8.2, 8.2, 3.3 Hz, 1H), 7.32 (m, 3H), 7.41 (m, 6H),
7.58 (m, 2H), 7.64 (m, 4H); 13C NMR (CDCl3) d 19.1
(s), 26.8 (q), 28.0 (t), 30.4 (t), 34.5 (t), 42.9 (d), 50.4 (q),
51.3 (d), 63.0 (t), 82.2 (d), 127.6 (d), 128.9 (d), 129.3
(d), 129.6 (d), 131.2 (s), 133.6 (s), 134.2 (d), 135.5(d),
171.0 (s), 173.6 (s); MS m/z (relative intensity) 505
(M ꢁ 57)+ (40), 427 (20), 269 (100), 199 (66); HRMS
Calc. for C28H29O5SiS (M ꢁ 57)+ 505.1505, found
505.1496.
To a stirred solution of (3S,4R,5R)-4-(2-hydroxyethyl)-
3-phenylthio-5- propyldihydrofuran-2-one (6 g, 0.021 mol)
in MeOH (71.4 mL, 0.3 M) was added KHSO5 (19.76 g,
0.032 mol) in H2O (42.8 mL, 0.5 M) at 0 °C. The mixture
was vigorously stirred for 5 h, until TLC showed comple-
tion. Then it was diluted with EtOAc and the organic
phase was washed with H2O and brine, dried, concen-
trated and purified by silica gel column chromatography,
4.5. General procedure to obtain a-benzenesulfonyl-b-
hydroxyethyl-c-lactones
25
yielding 13 (6.2 g, 93% yield) as an oil: ½aꢀD ¼ þ28:79 (c
4.5.1. Preparation of (3S,4R,5R)-3-benzenesulfonyl-4-(2-
hydroxyethyl)-5-propyldihydrofuran-2-one (13)
3.64, CHCl3); 1H NMR (CDCl3) d 0.88 (t, J = 7.3 Hz,
3H), 1.37 (m, 2H), 1.61 (m, 2H), 1.85 (m, 2H), 2.78 (br
s, 1H), 2.91 (m, 1H), 3.75 (m, 2H), 4.16 (m, 1H), 4.23
(d, J = 7.1 Hz, 1H), 7.55 (m, 2H), 7.66 (m, 1H), 7.90
(m, 2H); 13C NMR (CDCl3) d 13.6 (q), 18.6 (t), 36.0
(t), 37.1 (t), 38.8 (d), 59.7 (t), 69.3 (d), 84.3 (d), 129.2
(d), 129.9 (d), 134.7 (d), 136.6 (s), 167.4 (s); MS m/z
To a stirred solution of the lactone 8a (9 g, 0.029 mol) in
THF/H2O, 4:1 (146 mL, 0.2 M) was added NaOH (11.7 g,
0.29 mol). The reaction was stirred for 1 h, until starting
material was not detected by TLC. Then concentrated
HCl was added at 0 °C until pH 1 was reached and the

J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
5331
(relative intensity) 313 (M + 1)+ (31), 295 (7), 203 (45),
141 (44), 77 (100); HRMS Calc. for C15H21O5S
(M + 1)+ 313.1110, found 313.1111. Anal. Calc. for
C15H20O5S: C, 57.67, H, 6.45, S, 10.26. Found: C,
57.68, H, 6.65, S, 10.03.
4.6.3. Preparation of (3S,4R,5R)-3-benzenesulfonyl-3-pen-
tenyl-4-(2-hydroxyethyl)-5-propyldihydrofuran-2-one (14c)
Prepared from 13 (500 mg, 1.6 mmol) using 5-bromo-1-
pentene as alkylating agent to give 14c (353 mg, 58% yield)
25
as an oil: ½aꢀD ¼ þ22:6 (c 0.31, CHCl3); 1H NMR (CDCl3)
d 0.96 (t, J = 7.1 Hz, 3H), 1.33 (m, 2H), 1.44 (m, 2H), 1.53
(m, 2H), 1.96 (m, 2H), 2.16 (m, 2H), 3.17 (m, 1H), 3.75 (m,
1H), 3.82 (m, 1H), 4.05 (m, 1H), 4.99 (m, 2H), 5.65 (m,
1H), 7.67 (m, 2H), 7.71 (m, 1H), 7.94 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.6 (t), 28.6 (t), 29.2 (t), 30.1 (t),
30.8 (t), 36.8 (t), 40.8 (d), 61.3 (t), 75.1 (s), 83.6 (d), 116.0
(t), 124.0 (d), 129.2 (d), 129.6 (s), 130.9 (d), 136.8 (d),
174.5 (s); MS m/z (relative intensity) 381 (M + 1)+ (10),
269 (43), 125 (10), 69 (100); HRMS Calc. for C20H29O5S
(M + 1)+ 381.1735, found 381.1739. Anal. Calc. for
C20H28O5S: C, 63.13, H, 7.42, S, 8.43. Found: C, 63.30,
H, 7.55, S, 8.62.
4.6. General procedure for the alkylation of a-(benzenesulfo-
nyl)c-lactones
4.6.1. Preparation of (3S,4R,5R)-3-allyl-3-benzenesulfonyl-
4-(2-hydroxyethyl)-5-propyldihydrofuran-2-one (14a)
To a suspension of NaH (51,7 mg, 1,92 mmol, 80% in
mineral oil) in dry DMF (4 mL) under argon was added
dropwise the sulfone 13 (500 mg, 1.6 mmol) in dry DMF
(4 mL) at 0 °C. The reaction mixture was stirred for
15 min, after which time allyl bromide (166.4lL,
1.92 mmol) was added. The reaction was allowed to
warm to room temperature and stirred for 4 h. After this
period TLC showed complete conversion. Then to the
reaction mixture were added AcOH (50 lL) and H2O
(10 mL), and it was extracted with ether. The combined
organic phases were washed with a saturated aqueous
solution of NaHCO3 and brine, dried over MgSO4, con-
centrated and purified by column chromatography, giving
4.6.4. Preparation of (3S,4R,5R)-3-(2-methyl)allyl-3-ben-
zenesulfonyl-4-(2-hydroxyethyl)-5-propyl-dihydrofuran-2-
one (14d)
Prepared from 13 (500 mg, 1.6 mmol) using 3-chloro-2-
methyl-1-propene as alkylating agent to give 14d (352 mg,
25
60% yield) as an oil: ½aꢀD ¼ þ38:2 (c 1.07, CHCl3); 1H
25
14a (423 mg, 75% yield) as an oil: ½aꢀD ¼ þ39:9 (c 1.73,
NMR (CDCl3) d 0.87 (t, J = 7.3 Hz, 3H), 1.41 (m, 2H),
1.52 (m, 2H), 1.67 (s, 3H), 1.76 (m, 2H), 2.17 (m, 2H),
3.22 (m, 1H), 3.72 (m, 1H), 3.82 (m, 1H), 4.07 (m, 1H),
4.85 (s, 1H), 4.93 (s, 1H), 7.59 (m, 2H), 7.68 (m, 1H),
7.94 (m, 2H); 13C NMR (CDCl3) d 13.7 (q), 18.7 (t), 23.4
(q), 30.8 (t), 36.8 (t), 37.1 (t), 60.8 (t), 69.4 (d), 74.7 (s),
83.7 (d), 116.9 (t), 128.8 (d), 131.7 (d), 134.1 (s), 134.7
(d), 138.9 (s), 171.6 (s); MS m/z (relative intensity) 367
(M + 1)+ (39), 297 (10), 154 (100), 125 (24), 77 (54); HRMS
Calc. for C19H27O5S (M + 1)+ 367.1579, found 367.1571.
Anal. Calc. for C18H24O5S: C, 62.27, H, 7.15, S, 8.75.
Found: C, 62.47, H, 7.25, S, 8.87.
CHCl3); 1H NMR (CDCl3) d 0.86 (t, J = 7.2 Hz, 3H),
1.45 (m, 2H), 1.75 (m, 2H), 2.13 (m, 2H), 2.49 (br s,
1H), 2.80 (m, 2H), 3.16 (m, 1H), 3.71 (m, 1H), 3.84
(m, 1H), 3.98 (m, 1H), 5.19 (m, 2H), 5.56 (m, 1H),
7.59 (m, 2H), 7.68 (m, 1H), 7.92 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.6 (t), 30.6 (t), 34.0 (t), 36.5 (t),
40.9 (d), 60.4 (t), 75.1 (s), 83.5 (d), 122.3 (t), 129.93
(d), 129.8 (d), 131.5 (d), 134.3 (s), 134.7 (d), 170.7 (s);
MS m/z (relative intensity) 353 (M + 1)+ (13), 211
(100), 193 (64), 71 (95); HRMS Calc. for C18H25O5S
(M + 1)+ 353.1423, found 353.1423. Anal. Calc. for
C18H24O5S: C, 61.34, H, 6.86, S, 9.10. Found: C, 61.64,
H, 6.95, S, 8.87.
4.7. General procedure for the preparation of terminal
alkenes from primary alcohols
4.6.2. Preparation of (3S,4R,5R)-3-benzenesulfonyl-3-
butenyl-4-(2-hydroxyethyl)-5- propyldihydrofuran-2-one
(14b)
4.7.1. Preparation of (3S,4R,5R)-3,4-diallyl-3-benze-
nesulfonyl-5-propyldihydrofuran-2-one (10a)
Prepared from 13 (500 mg, 1.6 mmol) using 4-bromo-1-
butene as alkylating agent to give 14b (352 mg, 60% yield)
To a stirred solution of the alcohol 14a (R1 = Pr-n,
R4 = CH2CH@CH2) (400 mg, 1.14 mmol) in dry CH2Cl2
(3.8 mL) were added methyl sulfoxide (750 lL, 0.66 mL/
mmol) and triethylamine (1.11 mL, 7.9 mmol) at 0 °C.
The mixture was stirred for 15 min and then the complex
SO3 Æ Py (723 mg, 4.5 mmol) was added. The reaction was
allowed to warm to room temperature and stirred for
4 h. After this period TLC showed complete conversion.
The reaction was extracted with ether. The combined
organic phases were washed with H2O and brine, dried
and concentrated, yielding an oil of the crude aldehyde,
which was used without purification.
25
as an oil: ½aꢀD ¼ þ37:8 (c 0.27, CHCl3); 1H NMR
(CDCl3) d 0.86 (t, J = 7.1 Hz, 3H), 1.40 (m, 2H), 1.71
(m, 2H), 2.0 (m, 4H), 2.6 (br s, 1H), 3.16 (m, 1H), 3.74
(m, 1H), 3.82 (m, 1H), 4.04 (m, 1H), 4.97 (m, 2H), 5.63
(m, 1H), 7.57 (m, 2H), 7.67 (m, 1H), 7.91 (m, 2H); 13C
NMR (CDCl3) d 13.7 (q), 17.5 (t), 28.6 (t), 29.2 (t),
30.8 (t), 36.8 (t), 40.8 (d), 60.3 (t), 75.1 (s), 83.8 (d),
116.5 (t), 127.9 (d), 131.5 (d), 134.4 (s), 135.3 (d), 136.8
(d), 170.7 (s); MS m/z (relative intensity) 367 (M + 1)+
(39), 297 (10), 154 (100), 125 (24), 77 (54); HRMS Calc.
for C19H27O5S (M + 1)+ 367.1579, found 367.1571. Anal.
Calc. for C18H24O5S: C, 62.27, H, 7.15, S, 8.75. Found:
C, 62.47, H, 7.25, S, 8.87.
A solution of potassium hexamethyldisilazane (5.45 mL,
2.73 mmol) 0.5 M in toluene was added dropwise to a stirred
mixture of methyltriphenylphosphonium bromide (974 mg,

5332
J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
2.73 mmol) in THF (6 mL) at ꢁ40 °C. The mixture was stir-
red for 1 h at ꢁ40 °C to give a deep yellow coloration. A
solution of the crude aldehyde in THF (3 mL) was added
dropwise to the ylide solution and stirring was maintained
for 1 h at ꢁ40 °C. The reaction mixture was quenched by
dropwise addition of an ammonium chloride solution, fol-
lowed by warming to room temperature, at which point
ether was added. The organic layer was washed with water,
dried over MgSO4, and concentrated. The residue was puri-
fied by silica gel column chromatography to obtain the diene
377.1775. Anal. Calc. for C21H28O4S: C, 66.99, H, 7.50,
S, 8.52. Found: C, 67.27, H, 7.78, S, 8.04.
4.7.4. Preparation of (3S,4R,5R)-4-allyl-3-(2-methyl)allyl-
3-benzenesulfonyl-5- propyldihydrofuran-2-one (10d)
Prepared from 14d (300 mg, 0.82 mmol) to give 10d
25
(237 mg, 80% yield) as an oil: ½aꢀD ¼ þ48:8 (c 2.01,
CHCl3); 1H NMR (CDCl3) d 0.88 (t, J = 7.1 Hz, 3H),
1.34 (m, 2H), 1.49 (m, 2H), 1.69 (s, 3H), 1.74 (m, 1H),
2.43 (m, 1H), 2.72 (m, 2H), 3.11 (m, 1H), 4.09 (m, 1H),
4.87 (s, 1H), 4.95 (s, 1H), 5.09 (m, 2H), 5.79 (m, 1H),
7.69 (m, 2H), 7.79 (m, 1H), 7.94 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.5 (t), 23.4 (q), 32.8 (t), 37.0 (t),
37.1 (t), 44.0 (d), 73.9 (s), 84.0 (d), 116.7 (t), 117.5 (t),
128.7 (d), 131.5 (d), 134.4 (s), 134.5 (d), 137.7 (d), 139.1
(d), 171.4 (s); MS m/z (relative intensity) 363 (M + 1)+
(2), 257 (34), 221 (100), 179 (59), 77 (98); HRMS Calc.
for C20H27O4S (M + 1)+ 363.1630, found 363.1593. Anal.
Calc. for C20H26O4S: C, 66.27, H, 7.23, S, 8.85. Found:
C, 66.58, H, 7.35, S, 8.45.
25
10a (316 mg, 80% yield) as an oil: ½aꢀD ¼ þ32:5 (c 1.53,
CHCl3); 1H NMR (CDCl3) d 0.86 (t, J = 7.2 Hz, 3H), 1.27
(m, 2H), 1.45 (m, 2H), 1.75 (m, 1H), 2.33 (m, 1H), 2.76
(m, 2H), 3.06 (m, 1H), 4.03 (m, 1H), 5.10 (m, 2H), 5.22
(m, 2H), 5.58 (m, 1H), 5.78 (m, 1H), 7.60 (m, 2H), 7.72
(m, 1H), 7.94 (m, 2H); 13C NMR (CDCl3) d 13.7 (q), 18.4
(t), 32.8 (t), 33.9 (t), 37.2 (t), 43.6 (d), 74.2 (s), 83.8 (d),
117.6 (t), 122.0 (t), 129.2 (d), 130.1 (d), 131.4 (d), 133.4 (s),
134.6 (d), 135.4 (d), 170.6 (s); MS m/z (relative intensity)
349 (M + 1)+ (27), 207 (52), 91 (43), 71 (100); HRMS Calc.
for C19H25O4S (M + 1)+ 349.1473, found 349.1475. Anal.
Calc. for C19H24O4S: C, 65.49, H, 6.94, S, 9.20. Found: C,
65.83, H, 7.14, S, 8.86.
4.8. General experimental procedure for RCM of dienes
tethered to c-lactones
4.7.2. Preparation of (3S,4R,5R)-4-allyl-3-benzenesulfonyl-
3-butenyl-5-propyldihydrofuran-2-one (10b)
4.8.1. Preparation of (3R,3aR,7aS)-7a-(phenylsulfonyl)-3-
propyl-3a,4,7,7a-tetrahydroisobenzofuran-1(3H)-one (9a)
A 250 mL flask equipped with a condenser was flame-
dried in vacuo. The diene 10a (100 mg, 0.29 mmol) in
dry CH2Cl2 (71.8 mL, 4 mM) was added and the solution
was degassed by bubbling argon through the mixture for
1 h. Second-generation Grubbs catalyst 15 (24.4 mg,
10 mol%) in 2 mL of dry CH2Cl2 was added through the
condenser and the argon bubbling was continued for an
additional 30 min. The mixture was heated and stirred at
40 °C for 3 h until TLC showed the reaction was com-
plete. The solvent was removed in vacuo and the residue
was purified by silica gel chromatography to afford the
desired cyclic product 9a (78 mg, 85% yield) as an oil:
Prepared from 14b (300 mg, 0.82 mmol) to give 10b
25
(237 mg, 80% yield) as an oil: ½aꢀD ¼ þ57:4 (c 1.08,
1
CHCl3); H NMR (CDCl3) d 0.89 (t, J = 7.2 Hz, 3H),
1.33 (m, 2H), 1.48 (m, 2H), 1.78 (m, 1H), 2.02 (m, 3H),
2.23 (m, 1H), 2.70 (m, 1H), 3.10 (m, 1H), 4.07 (m, 1H),
5.01 (m, 2H), 5.13 (m, 2H), 5.63 (m, 1H), 5.78 (m, 1H),
7.56 (m, 2H), 7.68 (m, 1H), 7.92 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.5 (t), 28.5 (t), 29.4 (t), 30.0 (t),
37.5 (t), 43.4 (d), 74.1 (s), 83.9 (d), 116.4 (t), 117.8 (t),
128.8 (d), 131.4 (d), 134.6 (d), 134.7 (s), 135.1 (d), 135.4
(d), 170.6 (s); MS m/z (relative intensity) 363 (M + 1)+
(100), 255 (5), 154 (45), 109 (31), 77 (18); HRMS Calc.
for C20H27O4S (M + 1)+ 363.1630, found 363.1621. Anal.
Calc. for C20H26O4S: C, 66.27, H, 7.23, S, 8.85. Found:
C, 66.58, H, 7.35, S, 8.45.
25
½aꢀD ¼ þ1:07 (c 1.7, CHCl3); 1H NMR (CDCl3) d 0.94
(t, J = 7.3 Hz, 3H), 1.45 (m, 2H), 1.68 (m, 2H), 2.25 (m,
1H), 2.33 (m, 1H), 2.42 (m, 1H), 2.54 (m, 1H), 3.27 (m,
1H), 3.91 (m, 1H), 5.85 (m, 1H), 5.98 (m, 1H), 7.60 (m,
2H), 7.70 (m, 1H), 7.93 (m, 2H); 13C NMR (CDCl3) d
13.7 (q), 18.8 (t), 25.5 (t), 26.8 (t), 41.1 (d), 72.4 (s), 83.7
(d), 125.1 (d), 128.3 (d), 128.8 (d), 131.2 (d), 134.4 (s),
134.6 (d), 172.2 (s); MS m/z (relative intensity) 320 (M)+
(6), 179 (100), 123 (69), 77 (61); HRMS Calc. for
C17H20O4S (M)+ 320.1082, found 320.1087. Anal. Calc.
for C17H20O4S: C, 63.73, H, 6.29, S, 10.01. Found: C,
63.91, H, 6.32, S, 9.61.
4.7.3. Preparation of (3S,4R,5R)-4-allyl-3-benzenesulfonyl-
3-pentenyl-5-propyldihydrofuran-2-one (10c)
Prepared from 14c (300 mg, 0.79 mmol) to give 10c
25
(237 mg, 80% yield) as an oil: ½aꢀD ¼ þ56:9 (c 2.15,
1
CHCl3); H NMR (CDCl3) d 0.87 (t, J = 7.1 Hz, 3H),
1.42 (m, 5H), 1.57 (m, 1H), 1.76 (m, 1H), 2.03 (m, 3H),
2.17 (m, 1H), 2.66 (m, 1H), 3.05 (m, 1H), 4.05 (m, 1H),
4.97 (m, 2H), 5.12 (m, 2H), 5.65 (m, 1H), 5.76 (m, 1H),
7.58 (m, 2H), 7.67 (m, 1H), 7.92 (m, 2H); 13C NMR
(CDCl3) d 13.7 (q), 18.5 (t), 24.7 (t), 28.7 (t), 33.0 (t),
33.6 (t), 37.5 (t), 43.4 (d), 74.4 (s), 84.0 (d), 116.1 (t),
117.7 (t), 128.8 (d), 131.3 (d), 134.5 (d), 134.7 (s), 135.2
(d), 136.7 (d), 170.7 (s); MS m/z (relative intensity) 377
(M + 1)+ (84), 307 (12), 267 (94), 235 (100), 141 (40);
HRMS Calc. for C21H29O4S (M + 1)+ 377.1786, found
4.8.2. Preparation of (3R,3aR,8aS,Z)-8a-(phenylsulfonyl)-
3-propyl-3a,4,8,8a-tetrahydro-3H-cyclo-heptafuran-1(7H)-
one (9b)
Prepared from 10b (200 mg, 0.55 mmol) to give 9b
25
(157 mg, 85% yield) as an oil: ½aꢀD ¼ þ1:05 (c 3.06,
CHCl3); 1H NMR (CDCl3) d 0.93 (t, J = 7.2 Hz, 3H),

J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
5333
1.49 (m, 2H), 1.67 (m, 2H), 2.03 (m, 2H), 2.30 (m, 2H), 2.57
(m, 1H), 2.84 (m, 1H), 3.28 (m, 1H), 4.38 (m, 1H), 5.50 (m,
1H), 5.57 (m, 1H), 7.57 (m, 2H), 7.69 (m, 1H), 7.93 (m,
2H); 13C NMR (CDCl3) d 13.8 (q), 18.8 (t), 25.8 (t), 26.6
(t), 29.0 (t), 36.9 (t), 45.0 (d), 75.2 (s), 81.0 (d), 124.8 (d),
128.7 (d), 130.0 (d), 131.3 (d), 134.4 (s), 134.5 (d), 171.4
(s); MS m/z (relative intensity) 334 (M)+ (10), 267 (12),
193 (100), 147 (42); HRMS Calc. for C18H22O4S (M)+
334.1238, found 334.1225. Anal. Calc. for C18H22O4S: C,
64.64, H, 6.63, S, 8.76. Found: C, 65.23, H, 6.82, S, 9.05.
13C NMR (CDCl3) d 18.9 (s), 26.6 (q), 33.7 (t), 36.9 (t),
42.6 (d), 50.9 (d), 59.3 (t), 78.8 (d), 127.5 (d), 128.8 (d),
129.1 (d), 129.5 (d), 131.2 (s), 133.2 (s), 134.0 (d),
135.2(d), 173.6 (s), 175.9 (s); MS m/z (relative intensity)
477 (M ꢁ 57)+ (4), 349 (100), 255 (34), 199 (74); HRMS
Calc. for C26H25O5SiS (M ꢁ 57)+ 477.6321, found
477.6325.
From (2R,3R,4S)-[5-oxo-4-(phenylthio)-2-(2-tert-buty-
ldiphenylsilyloxy)-ethyl-tetrahydrofuran-3-yl]acetic
acid
(2.5 g, 4.68 mmol) was obtained (3S,4R,5R)-4-(2-hydroxy-
ethyl)-3-phenylthio-5-(2-tert-butyldiphenylsilyloxy)-ethyl-
dihydrofuran-2-one (2.09 g, 86% yield) as an oil:
4.8.3. Preparation of (3R,3aR,9aS,Z)-9a-(phenylsulfonyl)-
furan-1(3H)-
25
1
3-propyl-3a,4,7,8,9,9a-hexahydrocycloocta
one (9c)
½aꢀD ¼ þ12:89 (c 2.73, CHCl3); H NMR (CDCl3) d 1,04
(s, 9H), 1.69 (m, 3H), 1.84 (m, 2H), 2.22 (m, 1H), 3.62
(d, J = 10.1 Hz, 1H), 3.77 (m, 4H), 4.37 (ddd, J = 8.4,
8.4, 2.9 Hz, 1H), 7.31 (m, 3H), 7.41 (m, 6H), 7.57 (m,
2H), 7.63 (m, 4H); 13C NMR (CDCl3) d 19.2 (s), 26.6
(q), 28.9 (t), 34.5 (t), 43.5 (d), 52.0 (d), 59.7 (t), 60.0 (t),
77.2 (d), 127.5 (d), 128.8 (d), 129.0 (d), 129.5 (d), 131.5
(s), 133.3 (s), 133.5 (d), 135.3 (d), 174.6 (s); MS m/z (rela-
tive intensity) 463 (M ꢁ 57)+ (8), 385 (39), 255 (100), 199
(40); HRMS Calc. for C26H27O4SiS (M ꢁ 57)+ 463.1399,
found 463.1404.
Prepared from 10c (200 mg, 0.55 mmol) to give 9c
25
(83 mg, 45% yield) as an oil: ½aꢀD ¼ þ0:72 (c 2.5, CHCl3);
1H NMR (CDCl3) d 0.88 (t, J = 7.2 Hz, 3H), 1.34 (m,
4H), 1.67 (m, 2H), 2.03 (m, 2H), 2.25 (m, 2H), 2.40 (m,
2H), 3.07 (m, 1H), 4.24 (m, 1H), 5.68 (m, 1H), 5.80 (m,
1H), 7.59 (m, 2H), 7.68 (m, 1H), 7.97 (m, 2H); 13C NMR
(CDCl3) d 13.8 (q), 18.8 (t), 25.8 (t), 28.6 (t), 35.2 (t),
36.9 (t), 45.0 (d), 75.2 (s), 81.0 (d), 124.8 (d), 128.7 (d),
129.7 (d), 131.3 (d), 134.4 (s), 134.5 (d), 171.4 (s); MS m/
z (relative intensity) 348 (M)+ (2), 267 (7), 207 (68), 193
(59), 71 (100); HRMS Calc. for C19H24O4S (M)+
348.1395, found 348.1380. Anal. Calc. for C19H24O4S: C,
65.49, H, 6.94, S, 9.20. Found: C, 65.93, H, 7.38, S, 7.78.
From (3S,4R,5R)-4-(2-hydroxyethyl)-3-phenylthio-5-(2-
tert-butyl-diphenyl-silyloxy)-ethyl-dihydrofuran-2-one (1.8 g,
3.46 mmol) was obtained 16b (1.42 g, 80% yield) as an
25
oil: ½aꢀD ¼ þ7:61 (c 0.46, CHCl3); 1H NMR (CDCl3) d
1,04 (s, 9H), 1.85 (m, 2H), 2.15 (m, 1H), 2.38 (m, 2H),
3.56 (d, J = 9.6 Hz, 1H), 3.75 (m, 2H), 4.41 (m, 1H), 5.14
(m, 2H), 5.72 (m, 1H), 7.30 (m, 3H), 7.40 (m, 6H), 7.54
(m, 2H), 7.60 (m, 4H); 13C NMR (CDCl3) d 19.0 (s), 26.6
(q), 29.5 (t), 34.9 (t), 45.8 (d), 50.9 (d), 62.9 (t), 82.5 (d),
118.7 (t), 127.5 (d), 128.5 (d), 129.0 (d), 129.5 (d), 131.8
(s), 133.3 (d), 133.6 (d), 135.2(d), 174.2 (s); MS m/z (relative
intensity) 459 (M ꢁ 57)+ (27), 279 (18), 255 (100), 199 (29);
HRMS Calc. for C27H27O3SiS (M ꢁ 57)+ 459.1450, found
459.1439.
4.8.4. Preparation of (3R,3aR,7aS)-6-methyl-7a-(phen-
ylsulfonyl)-3-propyl-3a,4,7,7a-tetrahydro-iso-benzofuran-
1(3H)-one (9d)
Prepared from 10d (200 mg, 0.55 mmol) to give 9d
25
(157 mg, 85% yield) as an oil: ½aꢀD ¼ þ3:63 (c 1.9, CHCl3);
1H NMR (CDCl3) d 0.94 (t, J = 7.2 Hz, 3H), 1.44 (m, 2H),
1.62 (m, 2H), 1.72 (s, 3H), 2.18 (m, 1H), 2.29 (s, 2H), 2.55
(m, 1H), 3.24 (m, 1H), 3.88 (m, 1H), 5.63 (s, 1H), 7.59 (m,
2H), 7.73 (m, 1H), 7.93 (m, 2H); 13C NMR (CDCl3) d 13.7
(q), 18.8 (t), 23.0 (q), 29.7 (t), 31.8 (t), 36.8 (t), 41.0 (d), 73.2
(s), 84.0 (d), 121.1 (d), 128.6 (s), 128.8 (d), 131.1 (d), 134.1
(s), 134.6 (d), 172.1 (s); MS m/z (relative intensity) 334
(M)+ (10), 267 (12), 193 (100), 147 (42); HRMS Calc. for
C18H22O4S (M)+ 334.1238, found 334.1225. Anal. Calc.
for C18H22O4S: C, 64.64, H, 6.63, S, 8.76. Found: C,
65.23, H, 6.82, S, 9.05.
4.9.1. Preparation of (3S,4R,5R)-4-allyl-3-phenylthio-5-(3-
tert-butyldiphenylsilyloxy)-propyl-dihydrofuran-2-one (16c)
Prepared from 8c by the sequence outlined in Scheme 4.
From 8c (2.5 g, 4.44 mmol) was obtained (2R,3R,4S)-[5-
oxo-4-(phenylthio)-2-(3-tert-butyldiphenylsilyloxy)-propyl-
tetrahydro-furan-3-yl]acetic acid (2.19 g, 90% yield) as an
25
oil: ½aꢀD ¼ þ1:79 (c 1.73, CHCl3); 1H NMR (CDCl3) d
4.9. Preparation of (3S,4R,5R)-4-allyl-3-phenylthio-5-(2-
tert-butyldiphenylsilyloxy)-ethyl-dihydrofuran-2-one (16b)
1,03 (s, 9H), 1.63 (m, 2H), 1.78 (m, 2H), 2.37 (m, 1H),
2.64 (d, J = 5.8 Hz, 2H), 3.65 (m, 2H), 4.08 (d, J =
7.5 Hz, 1H), 4.22 (ddd, J = 8.2, 8.2, 3.8 Hz, 1H), 7.31 (m,
3H), 7.40 (m, 6H), 7.56 (m, 2H), 7.62 (m, 4H); 13C NMR
(CDCl3) d 19.2 (s), 26.8 (q), 28.0 (t), 30.5 (t), 34.2 (t), 42.6
(d), 51.2 (d), 63.0 (t), 82.2 (d), 127.7 (d), 128.7 (d), 129.0
(d), 129.3 (d), 131.0 (s), 133.7 (s), 134.4 (d), 135.5 (d),
173.6 (s), 175.9 (s); MS m/z (relative intensity) 491
(M ꢁ 57)+ (42), 413 (19), 269 (100), 199 (80); HRMS Calc.
for C27H27O5SiS (M ꢁ 57)+ 491.1348, found 491.1328.
From (2R,3R,4S)-[5-oxo-4-(phenylthio)-2-(3-tert-butyl-
diphenylsilyloxy)-propyl-tetrahydrofuran-3-yl]acetic acid
Prepared from 8b by the sequence outlined in Scheme 4:
From 8b (3 g, 5.47 mmol) was obtained (2R,3R,4S)-[5-
oxo-4-(phenylthio)-2-(2-tert-butyldiphenylsilyloxy)-ethyl-
tetrahydrofuran-3-yl]acetic acid (2.68 g, 92% yield) as an
25
1
oil: ½aꢀD ¼ þ13:81 (c 1.26, CHCl3); H NMR (CDCl3) d
1,04 (s, 9H), 1.60 (m, 2H), 1.83 (m, 2H), 2.42 (m, 1H),
2.68 (d, J = 5.7 Hz, 2H), 3.72 (m, 2H), 3.80 (d,
J = 10.2 Hz, 1H), 4.50 (ddd, J = 8.8, 8.8, 3.1 Hz, 1H),
7.31 (m, 3H), 7.39 (m, 6H), 7.55 (m, 2H), 7.62 (m, 4H);

5334
J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
(2 g, 3.64 mmol) was obtained (3S,4R,5R)-4-(2-hydroxy-
ethyl)-3-phenylthio-5-(3-tert-butyldiphenylsilyloxy)-propyl-
dihydrofuran-2-one (1.71 g, 88% yield) as an oil:
primary alcohols to obtain 12b (3S,4R,5R)-4,5-diallyl-3-
phenylthio-dihydrofuran-2-one (384.3 mg, 78% yield) as
25
1
an oil: ½aꢀD ¼ ꢁ26:0 (c 2.75, CHCl3); H NMR (CDCl3)
d 2.18 (m, 1H), 2.29 (m, 2H), 2.42 (m, 2H), 3.54 (d,
J = 9.5 Hz, 1H), 4.16 (ddd, J = 7.2, 7.2, 5.0 Hz, 1H), 5.14
(m, 4H), 5.68 (m, 2H), 7.32 (m, 3H), 7.56 (m, 2H); 13C
NMR (CDCl3) d 34.8 (t), 37.9 (t), 44.5 (d), 50.7 (d), 81.4
(d), 118.7 (t), 118.8 (t), 128.5 (d), 129.0 (d), 131.6 (s),
132.8 (d),133.2 (d), 133.9(d), 174.1 (s); MS m/z (relative
intensity) 274 (M)+ (83), 233 (20), 168 (71), 123 (47);
HRMS Calc. for C16H18O2S (M)+ 274.1028 , found
274.1033.
25
1
½aꢀD ¼ þ9:23 (c 1.95, CHCl3); H NMR (CDCl3) d 1,04
(s, 9H), 1.57 (m, 2H), 1.82 (m, 5H), 2.15 (m, 1H), 3.60 (d,
J = 10.1 Hz, 1H), 3.64 (m, 2H), 3.80 (m, 2H), 4.12 (ddd,
J = 8.1, 8.1, 3.1 Hz, 1H), 7.32 (m, 3H), 7.41 (m, 6H), 7.58
(m, 2H), 7.63 (m, 4H); 13C NMR (CDCl3) d 19.2 (s), 26.8
(q), 28.1 (t), 30.7 (t), 34.5 (t), 43.5 (d), 52.2 (d), 60.0 (t),
63.0 (t), 83.3 (d), 126.6 (d), 128.8 (d), 129.3 (d), 129.6 (d),
131.5 (s), 133.7 (s), 133.9 (d), 135.5 (d), 174.6 (s); MS m/z
(relative intensity) 477 (M ꢁ 57)+ (9), 399 (61), 269 (50),
199 (100); HRMS Calc. for C27H29O4SiS (M ꢁ 57)+
477.1556, found 477.1558.
4.10.1. Preparation of (3S,4R,5R)-4-allyl-5-(3-butenyl)-3-
phenylthio-dihydrofuran-2-one (12c)
Prepared from 16c by the sequence outlined in Scheme
4.
From (3S,4R,5R)-4-(2-hydroxyethyl)-3-phenylthio-5-(3-
tert-butyldiphenylsilyloxy)-propyl-dihydrofuran-2-one (1.5 g,
2.8 mmol) was obtained 16c (1.16 g, 78% yield) as an oil:
25
1
½aꢀD ¼ ꢁ3:65 (c 0.82, CHCl3); H NMR (CDCl3) d 1,03
(s, 9H), 1.64 (m, 2H), 1.81 (m, 2H), 2.13 (m, 1H), 2.38
(m, 2H), 3.56 (d, J = 9.7 Hz, 1H), 3.69 (m, 2H), 4.15
(ddd, J = 8.0, 8.0, 3.6 Hz, 1H), 5.12 (m, 2H), 5.76 (m,
1H), 7.34 (m, 3H), 7.43 (m, 6H), 7.59 (m, 2H), 7.66 (m,
4H); 13C NMR (CDCl3) d 19.0 (s), 26.7 (q), 28.0 (t), 30.8
(t), 34.9 (t), 45.7 (d), 50.9 (d), 62.9 (t), 82.5 (d), 118.7 (t),
127.5 (d), 128.5 (d), 129.0 (d), 129.5 (d), 131.8 (s), 132.9
(d), 133.3 (s), 133.8 (d), 135.3 (d), 174.2 (s); MS m/z (rela-
tive intensity) 473 (M ꢁ 57)+ (58), 269 (100), 199 (39);
HRMS Calc. for C28H29O3SiS (M ꢁ 57)+ 473.1607, found
473.1604.
From 16c (1 g, 1.88 mmol) was obtained (3S,4R,5R)-4-
allyl-5-(3-hydroxypropyl)-3-phenylthio-dihydrofuran-2-one
25
(507 mg, 92% yield) as an oil: ½aꢀD ¼ ꢁ4:92 (c 0.61,
CHCl3); 1H NMR (CDCl3) d 1.48 (br s, 1H), 1.55 (m,
2H), 1.64 (m, 2H), 2.04 (m, 1H), 2.39 (m, 2H), 3.53 (d,
J = 9.7 Hz, 1H), 3.63 (m, 2H), 4.15 (ddd, J = 8.1, 8.1,
3.2 Hz, 1H), 5.14 (m, 2H), 5.73 (m, 1H), 7.33 (m, 3H),
7.57 (m, 2H); 13C NMR (CDCl3) d 28.2 (t), 30.7 (t), 34.7
(t), 45.8 (d), 50.8 (d), 61.8 (t), 82.4 (d), 118.7 (t), 128.5
(d), 129.0 (d), 131.6 (s), 133.1 (d), 133.8 (d), 174.3 (s);
MS m/z (relative intensity) 292 (M)+ (100), 207 (9), 168
(12), 123 (18); HRMS Calc. for C16H20O3S (M)+
292.1133, found 292.1137.
4.10. Preparation of (3S,4R,5R)-4,5-diallyl-3-phenylthio-
dihydrofuran-2-one (12b)
From(3S,4R,5R)-4-allyl-5-(3-hydroxypropyl)-3-phenyl-
thio-dihydrofuran-2-one (400 mg, 1.36 mmol) was obtained
25
12c (315 mg, 80% yield) as an oil: ½aꢀD ¼ ꢁ5:67 (c 3.63,
1
Prepared from 16b by the sequence outlined in Scheme
4.
CHCl3); H NMR (CDCl3) d 1.68 (m, 1H), 1.71 (m, 1H),
2.12 (m, 3H), 2.35 (m, 2H), 3.54 (d, J = 9.6 Hz, 1H), 4.12
(ddd, J = 8.1, 8.1, 3.4 Hz, 1H), 5.0 (m, 2H), 5.12 (m,
2H), 5.72 (m, 2H), 7.34 (m, 3H), 7.56 (m, 2H); 13C NMR
(CDCl3) d 29.2 (t), 33.5 (t), 34.8 (t), 45.7 (d), 50.8 (d),
81.7 (d), 115.5 (t), 118.8 (t), 128.5 (d), 129.0 (d), 131.7 (s),
133.1 (d),133.8 (d), 136.7 (d), 174.2 (s); MS m/z (relative
intensity) 288 (M)+ (76), 247 (13), 168 (31), 149 (42), 123
(79); HRMS Calc. for C17H20O2S (M)+ 288.1184, found
288.1182.
To a stirred solution of 16b (1.3 g, 2.5 mmol) in dry
THF (12.5 mL, 0.2 M) was added tetra-butylammonium
fluoride 1 M in THF (3.02 mL, 3.02 mmol) at 0 °C. The
reaction was allowed to warm to room temperature and
stirred for 1 h, until TLC showed the end. The reaction
was extracted with ether and washed with brine, dried
and concentrated. The residue was purified by silica gel col-
umn chromatography to obtain (3S,4R,5R)-4-allyl-5-(2-
hydroxyethyl)-3-phenylthio-dihydrofuran-2-one (630.3 mg,
25
90% yield) as an oil: ½aꢀD ¼ ꢁ2:25 (c 0.8, CHCl3); 1H
4.11. Preparation of (3S,3aR,7aR)-3-phenylthio-3a,4,7,7a-
tetrahydro-isobenzofuran-2(3H)-one (11b)
NMR (CDCl3) d 1.66 (m, 2H), 1.91 (m, 1H), 2.14 (m,
1H), 2.40 (m, 2H), 3.54 (d, J = 9.7 Hz, 1H), 3.73 (t,
J = 5.1 Hz, 2H), 4.32 (ddd, J = 9.2, 9.2, 3.0 Hz, 1H), 5.15
(m, 2H), 5.75 (m, 1H), 7.33 (m, 3H), 7.56 (m, 2H); 13C
NMR (CDCl3) d 34.6 (t), 36.9 (t), 45.9 (d), 50.6 (d), 58.8
(t), 79.8 (d), 118.9 (t), 128.6 (d), 129.0 (d), 131.7 (s), 133.1
(d), 133.8(d), 174.3 (s); MS m/z (relative intensity) 278
(M)+ (100), 193 (18), 149 (29), 123 (33); HRMS Calc. for
C15H18O3S (M)+ 278.0977, found 278.0982.
The general experimental procedure for RCM of dienes
tethered to c-lactones was applied to 12b on a 200 mg
(0.72 mmol) scale yielding 11b (152 mg, 85% yield) as an
25
oil: ½aꢀD ¼ ꢁ27:5 (c 2.6, CHCl3); 1H NMR (CDCl3) d
2.07 (m, 2H), 2.21 (m, 1H), 2.31 (m, 1H), 2.57 (m, 1H),
3.63 (d, J = 12.1 Hz, 1H), 4.10 (ddd, J = 10.2, 10.2,
5.5 Hz, 1H), 5.65 (m, 2H), 7.32 (m, 3H), 7.56 (m, 2H);
13C NMR (CDCl3) d 28.5 (t), 30.4 (t), 45.4 (d), 52.3 (d),
78.6 (d), 123.7 (d), 126.4 (d), 128.3 (d), 128.9 (d), 131.6
(s), 133.5 (d), 174.0 (s); MS m/z (relative intensity) 246
Prepared from (3S,4R,5R)-4-allyl-5-(2-hydroxyethyl)-3-
phenylthio-dihydrofuran-2-one (500 mg, 1.79 mmol) using
the general procedure for the preparation of alkenes from

J.L. Ravelo et al. / Journal of Organometallic Chemistry 691 (2006) 5326–5335
5335
(M)+ (97), 149 (6), 109 (15), 93 (100); HRMS Calc. for
C14H14O2S (M)+ 246.0715, found 246.0714.
[4] W. Herz, H. Watanabe, M. Miyazaki, Y. Kishida, J. Am. Chem. Soc.
84 (1962) 2601–2610.
[5] S.M. Kupchan, R.J. Hemingway, D. Werner, A. Karim, A.T.
McPhail, G.A. Sim, J. Am. Chem. Soc. 90 (1968) 3596–3597.
[6] S.M. Kupchan, Y. Aynehchi, J.M. Cassady, H.K. Schnoes, A.
Burlingame, J. Org. Chem. 34 (1969) 3867–3875.
4.11.1. Preparation of (3S,3aR,8aR)-3-phenylthio-3a,4,8,8a-
tetrahydro-cycloheptenfuran-2(3H)-one (11c)
[7] (a) P.A. Grieco, Synthesis (1975) 67–82;
The general experimental procedure for RCM of dienes
tethered to c-lactones was applied to 12c on a 200 mg
(0.69 mmol) to give 11c (160 mg, 89% yield) as an oil:
(b) H.W.R. Hoffmann, J. Rabe, Angew. Chem. 97 (1985) 96–112;
(c) N. Petragnani, H.M.C. Ferraz, G.V.J. Silva, Synthesis (1986)
157–183;
25
1
½aꢀD ¼ ꢁ8:65 (c 2.38, CHCl3); H NMR (CDCl3) d 1.43
(m, 1H), 1.86 (m, 1H), 2.03 (m, 2H), 2.24 (m, 2H), 2.64
(m, 1H), 3.50 (d, J = 12.4 Hz, 1H), 4.02 (ddd, J = 9.7,
9.7, 2.6 Hz, 1H), 5.78 (m, 2H), 7.31 (m, 3H), 7.56 (m,
2H); 13C NMR (CDCl3) d 23.4 (t), 27.7 (t), 30.6 (t), 48.1
(d), 53.3 (d), 85.6 (d), 128.3 (d), 128.7 (d), 129.0 (d),
130.8 (d), 131.7 (s),133.5 (d), 173.9 (s); MS m/z (relative
intensity) 260 (M)+ (100), 162 (63), 149 (21), 107 (34);
HRMS Calc. for C15H16O2S (M)+ 260.0871, found
260.0866.
(d) , For precedents in the synthesis of carbocycles fused to c-lactones
´
using RCM, see:L.A. Paquette, J. Mendez-Andino, Tetrahedron Lett.
40 (1999) 4301–4304;
(e) M.E. Krafft, Y.Y. Cheung, S.A. Kerrigan, K.A. Abboud,
Tetrahedron Lett. 44 (2003) 839–843.
´
´
´
[8] C.M. Rodriguez, T. Martın, M.A. Ramırez, V.S. Martın, J. Org.
Chem. 59 (1994) 4461–4472.
´
´
´
[9] C.M. Rodriguez, T. Martın, M.A. Ramırez, V.S. Martın, J. Org.
Chem. 59 (1994) 8081–8091.
[10] (a) R.H. Grubbs, S. Chang, Tetrahedron 54 (1998) 4413–4450;
(b) S.K. Armstrong, J. Chem. Soc. Perkin Trans. 1 (1998) 371–388;
(c) M.E. Maier, Angew. Chem., Int. Ed. 39 (2000) 2073–2077;
(d) A. Furstner, Angew. Chem., Int. Ed. 39 (2000) 3012–3043.
¨
Acknowledgements
[11] (a) S.T. Diver, A.J. Giessert, Chem. Rev. 104 (2004) 1317–1382;
(b) K.C. Nicolaou, S.A. Snyder, in: Classics in Total Synthesis II,
Wiley–VCH, Weinheim, 2003;
(c) L. Yet, Chem. Rev. 100 (2000) 2963–3007.
[12] For a preliminary communication regarding the synthesis of a,b-fused
This research was supported by the Ministerio de Edu-
´
cacion y Ciencia of Spain, co-financed by the European Re-
gional Development Fund (CTQ2005-09074-C02-01/BQU)
and the Canary Islands Government.
´
´
systems, see: C.M. Rodrıguez, J.L. Ravelo, V.S. Martın, Org. Lett. 6
(2004) 4787–4789.
[13] R = C3H7 ꢁ n: Y. Gao, R.M. Hanson, J.M. Kluder, S.Y. Ko, H.
Masamune, K.B. Sharpless, J. Am. Chem. Soc. 109 (1987) 5765–
5780;
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[1] The Merck Index, 13th ed., Merck & CO., Inc. Whitehouse Station,
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´
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˜
2 3
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