4,5-Didehydro-7-silyloxymethyl-2-oxepanone and formal total syntheses of Hagen's gland lactones and trans-kumausynes

Article abstract of DOI:10.1016/j.tetlet.2006.08.059

A concise and enantiospecific route to the 2,6-dioxabicyclo[3.3.0]octan-3-one ring system from commercially available (R)-(+)- and (S)-(-)-glycidols is described. The key features involve ring closing metathesis to construct the 7-substituted-4,5-dehydro-

Full text of DOI:10.1016/j.tetlet.2006.08.059

Tetrahedron Letters 47 (2006) 7615–7618
4,5-Didehydro-7-silyloxymethyl-2-oxepanone and formal
total syntheses of Hagen’s gland lactones and trans-kumausynes
Divya Agrawal, Vardhineedi Sriramurthy and Veejendra K. Yadav*
Department of Chemistry, Indian Institute of Technology, Kanpur 208 016, India
Received 18 July 2006; revised 5 August 2006; accepted 17 August 2006
Available online 7 September 2006
Abstract—A concise and enantiospecific route to the 2,6-dioxabicyclo[3.3.0]octan-3-one ring system from commercially available
(R)-(+)- and (S)-(ꢀ)-glycidols is described. The key features involve ring closing metathesis to construct the 7-substituted-4,5-de-
hydro-2-oxepanone and its base-catalyzed single-step rearrangement into the 2,6-dioxabicyclo[3.3.0]octan-3-one skeleton. Using
this strategy, formal total syntheses of (7R)-cis-Hagen’s gland lactones and (+)- and (ꢀ)-trans-kumausynes have been achieved.
Ó 2006 Elsevier Ltd. All rights reserved.
H
H
H
The 2,6-dioxabicyclo[3.3.0]octan-3-one skeleton is pres-
ent in a number of natural products possessing diverse
biological activities. It serves also as a useful synthon
for several other compounds of this type. In particular,
plakortones, 1, represent a new family of drugs of sub-
stantial pharmacological interest that are relevant in
the correction of cardiac relaxation irregularities and
exhibit in vitro cytotoxic activity on the murine fibro-
sarcoma cell line.1 (+)-Goniofufurone, 2, is an antitumor
styryl-lactone.2 These lactones have generated consider-
able synthetic interest.3,4 The Hagen’s glands of some
parasitic wasps contain fragrant volatile biological
control agents that are rich in c-lactones including bicy-
clic materials 3a and 3b.5 There has been some interest in
the study of their biological roles.6
OH
H
O
O
O
O
O
R
Ph
O
O
OH
(+)-Goniofufurone (2)
Plakortones (1)
H
O
AcO
(CH2)nCH3
H
O
O
H
H
H
3a: n=3
3b: n=5
Br
trans-kumausyne (4a)
cis-Hagen's gland lactones
AcO
O
C
Br
O
O
H
H
H
H
Br
Br
cis-kumausyne (4b)
kumausallene (5)
The related kumausynes 4 and kumausallene 5 are struc-
turally diverse nonisoprenoid compounds, isolated from
the red algae of the genus Laurencia,7 which belong to a
growing family of halogenated natural products.8 These
materials have been demonstrated to exhibit diverse bio-
logical properties such as antitumor, antimicrobial,
immunosuppressant, antifeedant, and pesticidal activity.
Several syntheses of 49 and 510 have appeared. Most of
these approaches are based on a unified strategy that in-
Figure 1. Biologically active natural products containing the 2,6-
dioxabicyclo[3.3.0]octan-3-one skeleton.
volves the 2,6-dioxabicyclo[3.3.0]octan-3-one skeleton
as the single most important intermediate (Fig. 1).5e,11
The unique structural features and a wide range of
biological activities of the above natural products have
stimulated considerable synthetic interest aimed toward
the synthesis of the 2,6-dioxabicyclo[3.3.0]octan-3-
one skeleton. We have previously reported a racemic
synthesis of this bicyclic framework starting from 2-
carbomethoxycyclohexanone.12 This protocol, however,
was poor yielding. We report, herein, a new concise and
Keywords: Ring closing metathesis; Rearrangement; Natural products;
Bicyclic framework; Epoxidation.
*
Corresponding author. Tel.: +91 512 259 7439; fax: +91 512 259
7436; e-mail: vijendra@iitk.ac.in
0040-4039/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2006.08.059

7616
D. Agrawal et al. / Tetrahedron Letters 47 (2006) 7615–7618
Table 1. Diastereoselectivity in the epoxidation of 9 with different
reagents
O
OH
O
H
b
a
O
OH
OTBDPS
Epoxidation reagents
Products
Yield (%) (10:11)a
(
R
)-(+)-6
7
OTBDPS
m-CPBA
10 + 11
10 + 11
10 + 11
85 (2:1)
90 (1:1.5)
85b (1:3)
8
OxoneÒ/acetone
OxoneÒ/Shi’s diester
O
O
c
O
a Isolated yields. The diastereomeric ratios were determined from
integration of the relative 1H NMR signals.
b Yield is based on 55% conversion.
e
O
H
H
O
O
OTBDPS
O
10
TBDPSO
O
d
(+)-12a
O
O
O
OTBDPS
O
9
O
O
5% HF in CH3CN
rt, 90%
O
O
H
H
H
H
f
H
H
O
O
O
O
OTBDPS
11
OTBDPS
(+)-12a
OH
(+)-13
TBDPSO
(-)-12b
Scheme 2. Transformation of (+)-12a into (+)-13.
Scheme 1. Reagents and conditions: (a) (i) TBDPSCl, imidazole,
CH2Cl2, 0–25 °C, 3 h, 99% and (ii) vinylmagnesium bromide, Cu2I2,
THF, ꢀ20 °C, 45 min, 95%. (b) vinylacetic acid, DCC, DMAP,
CH2Cl2, 0–25 °C, 6 h, 89%; (c) 5 mol % of Grubbs’ second generation
catalyst, CH2Cl2, 25 °C, 10 h, 72%. (d) epoxidation; (e) DBU, CHCl3,
0–25 °C, 6 h, 85% and (f) K2CO3, DMF, 25 °C, 6 h, 90%.
12a. On screening suitable conditions for this transfor-
mation, DBU in CHCl3 offered the best result and
(+)-12a was formed in 85% yield after chromatographic
purification.
The spectral data of (ꢀ)-12b and its optical rotation
were consistent with those reported in the literature.11d
The elaboration of (ꢀ)-12b into (+)-trans-kumausyne
has been reported previously by Boukouvalas et al.11c
The diastereomer (+)-12a gave alcohol (+)-13 on cleav-
age of the TBDPS-ether with 5% HF in CH3CN in 90%
yield, Scheme 2. The spectral data of (+)-13 were in
agreement with those reported by Mereyala and Gadi-
kota.5d The elaboration of (+)-13 into (7R)-cis-Hagen’s
gland lactones has also been reported previously by
these authors.5d
enantiospecific route to this skeleton from commercially
available chiral glycidols by exploiting ring closing
metathesis13 to construct the 7-substituted-4,5-dide-
hydro-2-oxepanone followed by
a base-promoted
single-step rearrangement to the 7-substituted-2,6-dioxa-
bicyclo[3.3.0]octan-3-one skeleton to achieve formal
total syntheses of (7R)-cis-Hagen’s gland lactones and
(+)- and (ꢀ)-trans-kumausynes.
The syntheses of 7-tert-butyldiphenylsilyloxymethyl-
2,6-dioxabicyclo[3.3.0]octan-3-ones, (+)-12a and (ꢀ)-
12b, are illustrated in Scheme 1. It commences with
imidazole-promoted protection of the carbinol function
in (R)-(+)-glycidol 6 with TBDPSCl, followed by a reac-
tion with vinylmagnesium bromide (1.0 M in THF) in
Following a similar protocol with (S)-glycidol, we have
achieved the syntheses of (ꢀ)-12a and (+)-12b. The spec-
tral data of (+)-12b and its optical rotation were in
agreement with those reported in the literature.5d The
elaboration of (+)-12b into (ꢀ)-trans- kumausyne has
been reported previously by Osumi and Sugimura.11a
The enantiomeric purities of (+)-12a, (ꢀ)-12a, (+)-12b,
and (ꢀ)-12b were assessed by chiral HPLC (chiralcel-
ODH) using a 97.5:2.5 mixture of n-hexanes and i-PrOH
as solvent.
14
the presence of Cu2I2 to furnish 7 in 94% yield over
two steps. The oxirane ring cleavage took place with full
regiocontrol, giving a single product, as shown, in ac-
cord with the literature.14 Acylation with vinylacetic
acid in the presence of DCC and DMAP gave, after
chromatographic purification, the ring closing metathe-
sis precursor 8 in 89% yield. RCM of 8, catalyzed by
Grubbs’ second generation catalyst, proceeded well
under dilute conditions and the desired seven-membered
ring lactone 9 was isolated in 72% yield.
Mereyala and Gadikota have synthesized (+)-12b dur-
ing a formal total synthesis of (ꢀ)-trans-kumausyne over
10 steps in a 10.9% overall yield.5d The synthesis of (+)-
12b by Osumi and Sugimura proceeded in 11 steps in
11.3% overall yield.11a The synthesis of (+)-12b by Bou-
kouvalas et al. required only six steps and proceeded in a
30.9% overall yield11c and, thus, from comparable to the
present protocol. Lee et al. have synthesized the corre-
sponding aldehyde (replace CH2OSiPh2t-Bu by CHO)
over thirteen steps in a 10.7% overall yield.11b Gadikota
et al. have also achieved the synthesis of (ꢀ)-12b in a
projected formal total synthesis of (+)-trans-kumausyne
over 12 steps in 20.3% overall yield.11d Pradilla et al.
The exposure of 9 to m-CPBA in CH2Cl2 at 0 °C fur-
nished an easily separable mixture of oxiranes 10 and
11 in a 2:1 ratio and a combined 85% yield. This ratio
changed to 1:1.5 and 1:3 on oxidation with, respectively,
acetone dioxirane15 and the oxirane formed from Shi’s
diester.16 These oxidation results are collected in Table
1. The treatment of 11 with anhydrous K2CO3 in
DMF12 generated (ꢀ)-12b in 90% yield after chromato-
graphic purification. However, under these conditions,
10 did not undergo a complete conversion into (+)-

D. Agrawal et al. / Tetrahedron Letters 47 (2006) 7615–7618
7617
Kitching, W. J. Am. Chem. Soc. 2002, 124, 9718; (f)
Kowashi, S.; Ogamino, T.; Kamei, J.; Ishikawa, Y.;
Nishiyama, S. Tetrahedron Lett. 2004, 45, 4393; (g) Hayes,
P. Y.; Kitching, W. Heterocycles 2004, 62, 173.
have prepared the alcohol corresponding to (ꢀ)-12b in
five steps; the overall yield, however, was only 6.6%.9c
Mereyala and Gadikota have prepared (+)-13 for the
synthesis of (7R)-cis-Hagen’s gland lactones in a 12.8%
overall yield in nine steps.5d Our synthesis proceeds in
seven steps and generates (+)-13 in a 27% overall yield.
The synthesis of (ꢀ)-12a, a potential candidate for the
synthesis of (7S)-Hagen’s gland lactones, has not been
reported previously.
4. For syntheses of gonifufurone, see: (a) Gracza, T.; Jaeger,
V. Synlett 1992, 3, 191; (b) Murphy, P. J.; Dennison, S. T.
Tetrahedron 1993, 49, 6695; (c) Mukai, C.; Kim, I. J.;
Hanaoka, M. Tetrahedron Lett. 1993, 34, 6081; (d)
Gracza, T.; Jaeger, V. Synthesis 1994, 1359; (e) Shing, T.
K. M.; Tsui, H.-C.; Zhou, Z.-H. J. Org. Chem. 1995, 60,
3121; (f) Mereyala, H. B.; Gadikota, R. R.; Krishnan, R.
K. J. Chem. Soc., Perkin Trans. 1 1997, 23, 3567; (g) Yi,
X.-H.; Meng, Y.; Hua, X.-G.; Li, C.-J. J. Org. Chem.
1998, 63, 7472; (h) Su, Y.-L.; Yang, C.-S.; Teng, S.-J.;
Zhao, G.; Ding, Y. Tetrahedron 2001, 57, 2147; (i)
Popsavin, V.; Grabez, S.; Popsavin, M.; Krstic, I.; Kojic,
V.; Bogdanovic, G.; Divjakovic, V. Tetrahedron Lett.
2004, 51, 9409; (j) Ruiz, P.; Murga, J.; Carda, M.; Marco,
J. A. J. Org. Chem. 2005, 70, 713; (k) Prasad, K. R.;
Gholap, S. L. Synlett 2005, 19, 3018.
5. For characterization of 3a and 3b, see: Williams, H. J.;
Wong, M.; Wharton, R. A.; Vinson, S. B. J. Chem. Ecol.
1988, 14, 1727; For the syntheses of 3a and 3b, see: (a)
Paddon-Jones, G. C.; Moore, C. J.; Brecknell, D. J.;
Ko¨nig, W. A.; Kitching, W. Tetrahedron Lett. 1997, 38,
3479; (b) Mereyala, H. B.; Gadikota, R. R. Chem. Lett.
1999, 3, 273; (c) Mereyala, H. B.; Gadikota, R. R.;
Sunder, K. S.; Shailaja, S. Tetrahedron 2000, 56, 3021; (d)
Mereyala, H. B.; Gadikota, R. R. Tetrahedron: Asymme-
try 2000, 11, 743; (e) Paddon-Jones, G. C.; McErlean, C.
S. P.; Hayes, P.; Moore, C. J.; Ko¨nig, W. A.; Kitching, W.
J. Org. Chem. 2001, 66, 7487.
In summary, facile enantiospecific syntheses of 7-t-butyl-
diphenylsilyloxymethyl-2,6-dioxabicyclo[3.3.0]octan-3-
ones, (+)-12a, (ꢀ)-12a, (+)-12b, and (ꢀ)-12b have been
achieved from commercially available chiral glycidols in
30%, 31%, 35% and 36% overall yields, respectively,
over six steps. The yields of (+)-12a and (ꢀ)-12a are
based on the oxidation results obtained from m-CPBA
and those of (+)-12b and (ꢀ)-12b are based on the
oxidation results obtained from application of the
dioxirane formed from Shi’s diester.
The key features of our strategy are ring closing meta-
thesis to construct the 7-t-butyldiphenylsilyloxymethyl-
4,5-didehydro-2-oxepanone 9 and a base-promoted
one-step rearrangement of 7-t-butyldiphenylsilyloxym-
ethyl-4,5-epoxy-2-oxepanones 10/11 into the requisite
bicyclic skeleton. We have demonstrated the utility of
this approach for the formal total syntheses of (7R)-
cis-Hagen’s gland lactones and (+)- and (ꢀ)-trans kum-
ausynes herein.17 A similar application to the synthesis
of goniofufurone is currently under investigation.
6. (a) Hagen, K. L. Proc. Hawaii Entamol. Soc. 1953, 15, 115;
(b) Buckingham, G. R. Ann. Entamol. Soc. Am. 1968, 61,
233.
7. Suzuki, T.; Koizumi, K.; Suzuki, M.; Kurosawa, E. Chem.
Lett. 1983, 1639, 1643.
8. Faulkner, D. J. Nat. Prod. Rep. 1999, 16, 155.
9. (a) Brown, M. J.; Harrison, T.; Overman, L. E. J. Am.
Chem. Soc. 1991, 113, 5378; (b) Olivier, A.; Cecile, G.;
Yannick, L.; Liliana, P.-R. Tetrahedron 1997, 53, 2835; (c)
de la Pradilla, R. F.; Montero, C.; Priego, J.; Martinez-
Cruz, L. A. J. Org. Chem. 1998, 63, 9612; (d) Garcia, C.;
Martin, T.; Martin, V. S. J. Org. Chem. 2001, 66, 1420; (e)
Chandler, C. L.; Phillips, A. J. Org. Lett. 2005, 16, 3493;
(f) de la Pradilla, R. F.; Carolina, A.; Alejandro, C.; Jorge,
F.; Pilar, M.; Carlos, M.; Mercedes, U.; Alma, V. J. Org.
Chem. 2005, 70, 10693.
10. (a) Grese, T. A.; Hutchinson, K. D.; Overman, L. E. J.
Org. Chem. 1993, 58, 2468; (b) Lee, E.; Yoo, S.; Choo, H.;
Song, H. Y. Tetrahedron Lett. 1998, 39, 317; (c) Andrew,
E. P.; Srinivasa, M. V.; Jamie, D. R.; Arnold, L. R.
Angew. Chem., Int. Ed. 1999, 38, 3175.
Acknowledgments
V.K.Y. thanks CSIR, Government of India, for funding
the research. D.A. and V.S. thank the CSIR and IIT
Kanpur for a JRF and an SRF, respectively.
References and notes
1. (a) Stierle, D. B.; Faulkner, D. J. J. Org. Chem. 1980, 45,
3396; (b) Patil, A. D.; Freyer, A. J.; Bean, M. F.; Carte, B.
K.; Westley, J. W.; Johnson, R. K.; Lahouratate, P.
Tetrahedron 1996, 52, 377; (c) Caffierei, F.; Fattorusso, E.;
Taglialatela-Scafati, O.; Ianaro, A. Tetrahedron 1999, 53,
7045; (d) Caffierei, F.; Fattorusso, E.; Taglialatela-Scafati,
O.; Rosa, M. D.; Ianaro, A. Tetrahedron 1999, 55, 13831;
(e) Gochfeld, D. J.; Hamann, M. T. J. Nat. Prod. 2001, 64,
1477.
2. (a) Fang, X. P.; Anderson, J. E.; Chang, C. J.; Fanwick, P.
E.; McLaughlin, J. L. J. Chem. Soc., Perkin Trans. 1 1990,
1655; (b) Mereyala, H. B.; Gadikota, R. R.; Joe, M.;
Arora, S. K.; Dastidar, S. G.; Agarwal, S. Bioorg. Med.
Chem. 1999, 7, 2095.
11. (a) Osumi, K.; Sugimura, H. Tetrahedron Lett. 1995, 36,
5789; (b) Lee, E.; Yoo, S.; Choo, Y. S.; Cheon, H. S.;
Chong, Y. H. Tetrahedron Lett. 1997, 38, 7757; (c)
Boukouvalas, J.; Fortier, G.; Radu, I.-I. J. Org. Chem.
1998, 63, 916; (d) Gadikota, R. R.; Callam, C. S.; Lowary,
T. L. J. Org. Chem. 2001, 66, 9046.
12. Jeyaraj, D. A.; Kapoor, K. K.; Yadav, V. K.; Gauniyal,
H. M.; Parvez, M. J. Org. Chem. 1998, 63, 287.
13. For reviews on ring closing metathesis, see: (a) Grubbs, R.
H.; Miller, S. J.; Fu, G. C. Acc. Chem. Res. 1995, 28, 446; (b)
Schuster, M.; Blechert, S. Angew. Chem., Int. Ed. 1997, 36,
2036; (c) Grubbs, R. H.; Chang, S. Tetrahedron 1998, 54,
3. For the reported approaches to and syntheses of plakor-
tones, see: (a) Paddon-Jones, G. C.; Hungerford, N. L.;
Hayes, P.; Kitching, W. Org. Lett. 1999, 1, 1905; (b)
Bittner, C.; Burgo, A.; Murphy, P. J.; Sung, C. H.;
Thornhill, A. J. Tetrahedron Lett. 1999, 40, 3455; (c)
Semmelhack, M. F.; Shanmugam, P. Tetrahedron Lett.
2000, 41, 3567; (d) Lee, H. K.; Wong, H. N. C. J. Chem.
Soc., Chem. Commun. 2002, 18, 2114; (e) Hayes, P.;
4413; (d) Furstner, A. Angew. Chem., Int. Ed. 2000, 39, 3013.
¨
14. Bonini, C.; Chiummiento, L.; Lopardo, M. T.; Pullez, M.;
Colobert, F.; Solladie, G. Tetrahedron Lett. 2003, 44,
2695.

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D. Agrawal et al. / Tetrahedron Letters 47 (2006) 7615–7618
15. (a) Curci, R.; Fiorentino, M.; Troisi, L.; Edwards, J. O.;
Pater, R. H. J. Org. Chem. 1980, 45, 4758; (b) Murray, R.
W. Chem. Rev. 1989, 89, 1187.
16. (a) Tu, Y.; Wang, Z.-X.; Shi, Y. J. Am. Chem. Soc. 1996,
118, 9806; (b) Nieto, N.; Molas, P.; Benet-Buchholz, J.;
Vidal-Ferran, A. J. Org. Chem. 2005, 70, 10143.
Anal. Calcd for C23H28O4Si: C, 69.66; H, 7.12. Found: C,
69.60; H, 7.10.
Spectral data of 11. 1H NMR (400 MHz, CDCl3):
d = 7.66–7.64 (m, 4H), 7.47–7.38 (m, 6H), 4.52–4.47 (m,
1H), 3.78 (dd, J = 10.5, 5.1 Hz, 1H), 3.58 (dd, J = 10.5,
6.6 Hz, 1H), 3.39–3.22 (m, 4H), 2.39–2.25 (m, 2H), 1.07 (s,
9H). 13C NMR (100 MHz, CDCl3): d 168.0, 135.5, 132.82,
132.77, 130.0, 127.8, 76.1, 65.4, 52.6, 50.7, 35.4, 28.8, 26.8,
19.2. IR (KBr) 2928, 2857, 1741, 1426, 1110 cmꢀ1. Anal.
Calcd for C23H28O4Si: C, 69.66; H, 7.12. Found: C, 69.56;
H, 7.15.
17. Spectral data of tert-butyldiphenylsilyl ether of (S)-gly-
1
cidol: H NMR (400 MHz, CDCl3): d 7.70–7.67 (m, 4H),
7.44–7.36 (m, 6H), 3.86 (dd, J = 12.0, 3.2 Hz, 1H), 3.70
(dd, J = 12.0, 4.9 Hz, 1H), 3.14–3.10 (m, 1H), 2.73 (dd,
J = 5.1, 4.2 Hz, 1H), 2.60 (dd, J = 5.1, 2.7 Hz, 1H), 1.06 (s,
9H). 13C NMR (100 MHz, CDCl3): d 135.59, 135.54, 133.3,
129.7, 127.7, 64.3, 52.3, 44.4, 26.7, 19.2. IR (neat) 2931,
1467, 1110, 823, 704 cmꢀ1. Anal. Calcd for C19H24O2Si: C,
73.03; H, 7.74. Found: C, 72.90; H, 7.80.
Spectral data of (1R,5R,7S)-7-tert-butyldiphenylsilyl-
oxymethyl-2,6-dioxabicyclo[3.3.0]octan-3-one,
(+)-12a.
½aꢁD +24.7 (c 1.0, CHCl3) [lit.5e ½aꢁD25 +25.0 (c 0.8, CHCl3)],
ee 98%. 1H NMR (400 MHz, CDCl3): d 7.66–7.62 (m, 4H),
7.43–7.35 (m, 6H), 5.11 (dd, J = 4.6 Hz, 1H), 4.82–4.79 (m,
1H), 4.31–4.26 (m, 1H), 3.80 (dd, J = 11.0, 3.4 Hz, 1H),
3.63 (dd, J = 11.0, 3.6 Hz, 1H), 2.71–2.69 (m, 2H), 2.34
(dd, J = 14.2, 6.4 Hz, 1H), 2.21–2.14 (m, 1H), 1.04 (s, 9H).
13C NMR (100 MHz, CDCl3): d 175.8, 135.5, 133.1,
129.81, 129.76, 127.7, 85.1, 79.4, 78.6, 65.4, 36.9, 34.4,
26.8, 19.2. IR (KBr) 2927, 1785, 1429, 1110 cmꢀ1. Anal.
Calcd for C23H28O4Si: C, 69.66; H, 7.12. Found: C, 69.70;
H, 7.10.
25
Spectral data of (S)-1-(tert-butyldiphenylsilyloxy)-4-
1
penten-2-ol (7). H NMR (400 MHz, CDCl3): d 7.67–7.65
(m,4H), 7.45–7.36 (m, 6H), 5.82–5.75 (m, 1H), 5.09–5.03
(m, 2H), 3.80–3.75 (m, 1H), 3.67 (dd, J = 10.2, 3.9 Hz, 1H),
3.55 (dd, J = 10.2, 6.8 Hz, 1H), 2.26–2.22 (m, 2H), 1.07
(s, 9H). 13C NMR (100 MHz, CDCl3): d 135.5, 134.3,
133.1, 129.7, 129.4, 127.7, 127.5, 117.3, 71.2, 67.3, 37.5,
26.8, 19.2. IR (neat) 3071, 2931, 1428 cmꢀ1. Anal. Calcd
for C21H28O2Si: C, 74.07; H, 8.29. Found: C, 74.10;
H, 8.30.
Spectral data of (S)-1-(tert-butyldiphenylsilyloxy)pent-4-
en-2-yl-3-butenoate (8). 1H NMR (400 MHz, CDCl3): d
7.68–7.64 (m, 4H), 7.45–7.35 (m, 6H), 5.94–5.86 (m, 1H),
5.75–5.68 (m, 1H), 5.17–5.03 (m, 5H), 3.74–3.67 (m, 2H),
3.11–3.00 (m, 2H), 2.48–2.42 (m, 1H), 2.39–2.32 (m, 1H),
1.05 (s, 9H). 13C NMR (100 MHz, CDCl3): d 170.9, 135.6,
135.5, 133.3, 133.2, 130.3, 129.9, 129.6, 127.6, 118.4, 117.9,
73.7, 64.3, 39.2, 35.0, 26.7, 19.2. IR (neat) 3073, 2933, 1738,
1428 cmꢀ1. Anal. Calcd for C25H32O3Si: C, 73.49; H, 7.89.
Found: C, 73.40; H, 7.90.
Spectral data of (1S,5S,7S)-7-tert-butyldiphenylsilyloxy-
25
methyl-2,6-dioxabicyclo[3.3.0]octan-3-one, (ꢀ)-12b. ½aꢁD
25
–25.8 (c 0.67, CHCl3) [lit.14d ½aꢁD –26.0 (c 1.5, CHCl3)],
ee 97.4%. 1H NMR (400 MHz, CDCl3): d 7.67–7.64 (m,
4H), 7.45–7.36 (m, 6H), 5.03–5.01 (m, 1H), 4.59–4.57 (m,
1H), 4.15–4.12 (m, 1H), 3.76–3.67 (m, 2H), 2.71 (d,
J = 4.1 Hz, 2H), 2.40–2.33 (m, 1H), 2.24–2.18 (m, 1H),
1.05 (s, 9H). 13C NMR (100 MHz, CDCl3): d 175.2, 135.6,
133.33, 133.26, 129.7, 127.7, 84.3, 80.6, 78.9, 65.5, 36.4,
34.6, 26.8, 19.2. IR (KBr) 3071, 2928, 1783, 1428,
1113 cmꢀ1. Anal. Calcd for C23H28O4Si: C, 69.66; H,
7.12. Found: C, 69.60; H, 7.15.
Spectral data of (S)-7-((tert-butyldiphenylsilyloxy)methyl)-
4,5-dehydro-oxepan-2-one (9). 1H NMR (400 MHz,
CDCl3): d 7.66–7.64 (m, 4H), 7.44–7.36 (m, 6H), 5.73–
5.68 (m, 1H), 5.54–5.50 (m, 1H), 4.73–4.67 (m, 1H), 3.84
(dd, J = 10.8, 5.6 Hz, 1H), 3.67 (dd, J = 10.8, 6.1 Hz, 1H),
3.60 (dd, J = 16.6, 3.0 Hz, 1H), 3.01 (dd, J = 16.6, 8.5 Hz,
1H), 2.57–2.52 (m, 1H), 2.42–2.34 (m, 1H), 1.05 (s, 9H).
13C NMR (100 MHz, CDCl3): d 172.1, 135.6, 133.0, 129.9,
128.8, 127.8, 127.7, 118.6, 65.5, 33.9, 32.2, 29.7, 26.8, 19.2.
IR (neat) 3042, 2932, 1742, 1428 cmꢀ1. Anal. Calcd for
C23H28O3Si: C, 72.59; H, 7.42. Found: C, 72.45; H, 7.35.
Spectral data of 10. 1H NMR (400 MHz, CDCl3): d 7.67–
7.65 (m, 4H), 7.46–7.37 (m, 6H), 4.16–4.11 (m, 1H), 3.79
(dd, J = 11.2, 5.4 Hz, 1H), 3.69 (dd, J = 10.7, 5.4 Hz, 1H),
3.31–3.27 (m, 1H), 3.22–3.21 (m, 1H), 3.14 (dd, J = 15.4,
8.1 Hz, 1H), 2.91 (dd, J = 15.4, 2.4 Hz, 1H), 2.51 (d,
J = 16.1 Hz, 1H), 2.20–2.13 (ddd, J = 16.1, 11.2, 2.4 Hz,
1H), 1.06 (s, 9H). 13C NMR (100 MHz, CDCl3): d 169.6,
135.6, 132.8, 129.9, 127.8, 73.6, 65.0, 52.6, 48.6, 34.1, 30.4,
Spectral data of (ꢀ)-12a. The 1H and 13C spectral data
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were identical to that of (+)-12a. ½aꢁD ꢀ25.0 (c 0.8, CHCl3),
ee 98%. Anal. Calcd for C23H28O4Si: C, 69.66% H, 7.12.
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Found: C, 69.55; H, 7.10. Spectral data of (+)-12b. ½aꢁD
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+25.0 (c 0.7, CHCl3), [lit.5d ½aꢁD +25.4 (c 0.8, CHCl3)], ee
98%. The 1H and 13C spectral data were identical to that of
(ꢀ)-12b. Anal. Calcd for C23H28O4Si: C, 69.66; H, 7.12.
Found: C, 69.50; H, 7.04.
Spectral data of (1R,5R,7S)-7-hydroxymethyl-2,6-dioxabi-
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cyclo[3.3.0]octan-3-one, (+)-13. ½aꢁD +41.5 (c 1.0, CHCl3),
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[lit.5d ½aꢁD +41.7 (c 1.4, CHCl3)], ee 98%. 1H NMR
(400 MHz, CDCl3): d 5.15 (dd, J = 4.6 Hz, 1H), 4.85–4.83
(m, 1H), 4.32–4.26 (m, 1H), 3.86 (dd, J = 12.0, 2.7 Hz, 1H),
3.56 (dd, J = 12.0, 4.6 Hz, 1H), 2.81–2.67 (m, 2H), 2.32
(dd, J = 14.2, 5.6 Hz, 1H), 2.12–2.05 (m, 1H), 1.87 (br s,
1H). 13C NMR (100 MHz, CDCl3): d 175.6, 85.0, 79.0,
78.4, 63.3, 36.8, 33.8. IR (neat) 3367, 2925, 1750,
1040 cmꢀ1. Anal. Calcd for C7H10O4: C, 53.16; H, 6.37.
Found: C, 53.10; H, 6.40.
26.8, 19.2. IR (KBr) 2928, 2850, 1730, 1426, 1109 cmꢀ1
.