A. Kamimura et al. / Tetrahedron Letters 43 (2002) 6189–6191
6191
J. Org. Chem. 1999, 64, 1197; (b) Basavaiah, D.; Satya-
narayana, T. Org. Lett. 2001, 3, 3619; (c) Basavaiah, D.;
Muthukumaran, K.; Sreenivasulu, B. Synthesis 2001, 545;
(d) Basavaiah, D.; Hyma, R. S.; Muthukumaran, K.;
Kumaragurubaran, N. Synthesis 2001, 217.
TBSO
Me
O
OAc O
a - d
OBu-t
Me
NHOBn
SEt
SEt
syn-2e
4
6. (a) Perlmutter, P.; Tabone, M. Tetrahedron Lett. 1988,
29, 949; (b) Perlmutter, P.; Tabone, M. J. Org. Chem.
1995, 60, 6515; (c) Lawrence, R. M.; Perlmutter, P.
Chem. Lett. 1992, 305; (d) Guthrie-Strachan, J. J.; Kaye,
P. T.; Whittaker, R. E. Synth. Commun. 1998, 28, 2601.
7. Conversion of a methylene unit to methyl by hydrogena-
tion reaction, see: (a) Mateus, C. R.; Feltrin, M. P.;
Costa, A. M.; Coelho, F.; Almeida, W. P. Tetrahedron
2001, 57, 6901; (b) Farrington, E.; Franchini, N. C.;
Brown, J. M. Chem. Commun. 1998, 277; (c) Brown, J.
M.; Evans, P. L.; James, A. P. Org. Synth. 1990, 68, 64.
8. Preparation of 2c. To a solution of EtSH (0.32 mL, 4.32
mmol) in dry THF (distilled over potassium-benzophe-
none ketyl, 15 mL) was added BuLi (1.6 M, 0.25 mL,
0.40 mmol) at −50°C. Methyl 2-[1-(tert-butyldimethylsilyl-
oxy)ethyl]acrylate (0.923 g, 3.78 mmol) was added to the
solution at −50°C, and the resulting reaction mixture was
allowed to stir at the same temperature for 15 h. HCl aq.
(1 M, 40 mL) was added to the mixture and the organic
phase was separated. The water phase was extracted with
EtOAc (3×70 mL) and the combined organic phase was
dried over Na2SO4. After filtration, the organic solvent
was removed in vacuo and the residue was purified
through flash chromatography (hexane then hexane/ether
30:1 v/v) to give adduct 2c in 94% yield (1.08 g, 3.54
OAc
H
Me
e
N
O
OBn
5
Scheme 4. Reagents and conditions: (a) TBAF, 99%; (b)
Ac2O, DMAP, 87%; (c) TsOH (10 mol%), wet benzene,
reflux, 93%; (d) EDCI, NH2OBn, 84%; (e) AgClO4, MeI, then
K2CO3, 64%
Acknowledgements
The present work was partially supported by a Grant-
in-Aid (11640536) from the Ministry of Education,
Science, Sports and Culture, Japan.
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