N. Brosse, B. Jamart-Gre´goire / Tetrahedron Letters 43 (2002) 249–251
251
3. For recent reviews about nitrogen protecting groups, see:
Theodoridis, G. Tetrahedron 2000, 56, 2339–2358; Jarow-
icki, K.; Kocienski, P. J. Chem. Soc., Perkin Trans. 1
1999, 1589–1615.
4. (a) Brosse, N.; Pinto, M.-F.; Jamart-Gre´goire, B. J. Org.
Chem. 2000, 65, 4370–4374; (b) Brosse, N.; Pinto, M.-F.;
Bodiguel, J.; Jamart-Gre´goire, B. J. Org. Chem. 2001, 66,
2869–2873.
5. (a) Osby, J. O.; Michael, M. G.; Martin, G.; Ganem, B.
Tetrahedron Lett. 1984, 25, 2093–2096; (b) Merricks, D.;
Sammes, P. G.; Walker, E. R. H.; Henrick, K.;
McPartlin, M. M. J. Chem. Soc., Perkin Trans. 1 1991,
2169–2176; (c) Stocksdale, M. G.; Ramurthy, S.; Miller,
M. J. J. Org. Chem. 1998, 63, 1221–1225.
6. Kotsuki, H.; Ohishi, T.; Araki, T.; Arimura, K. Tetra-
hedron Lett. 1998, 39, 4869–4870 and references cited
therein.
2H), 4.67 (s, 2H), 1.36, 1.29 (2s, 18H); 13C NMR: l
155.5, 150.3, 136.3, 135.4, 130.6, 130.2, 128.8, 128.7,
128.6, 128.4, 84.0, 68.7, 68.3, 54.9, 53.9, 28.1. 3 R=
OCH2Ph, R%=CH(CH3)COOEt: 1H NMR (CDCl3): l
7.38–7.26 (m, 5H), 5.29–5.17 (m, 2H), 4.58 (q, J=7 Hz,
1H), 4.20 (t, J=7 Hz, 3H), 1.51, 1.47, 1.45, 1.40 (4s,
18H), 1.36 (d, J=7 Hz, 3H), 1.26 (t, J=7 Hz, 3H). 13C
NMR: l 155.5, 150.3, 136.3, 135.4, 130.6, 130.2, 128.8,
128.7, 128.6, 128.4, 84.0, 68.7, 68.3, 54.9, 53.9, 28.1.4
R=Ph, R%=CH3: 1H NMR (CDCl3): l 7.44–7.22 (m,
5H), 3.23 (s, 3H), 1.35 (s, 9H); 13C NMR: l 134.9, 130.6,
1
128.3, 127.6, 82.0, 28.4. 4 R=Ph, R%=CH2Ph: H NMR
(CDCl3): l 7.62–7.22 (m, 10H), 6.75 (s, 1H), 6.61–4.07
(m, 2H), 1.31 (s, 9H). 13C NMR: l 154.4, 136.2, 135.3,
130.5, 129.1, 129.0, 128.3, 128.0, 127.7, 82.0, 28.6. 4
R=CH3, R%=CH3: 1H NMR (CDCl3): l 7.71 (s, 1H),
3.05 (s, 3H), 2.01 (s, 3H), 1.12 (s, 9H).13C NMR: l 174.3,
7. (a) Motawia, M. S.; Wengel, J.; Abdel-Medig, A. E.-S.;
Peterson, E. B. Synthesis 1989, 384–387; (b) Sen, S. E.;
Roach, S. L. Synthesis 1995, 756–758.
8. Burk, C. M. J.; Allen, J. G. J. Org. Chem. 1997, 62,
7054–7057.
1
154.7, 82.0, 36.0, 28.5, 20.7. 4 R=CH3, R%=CH2Ph: H
NMR (CDCl3): l 7.34–7.12 (m, 5H), 5.36–4.27 (m, 2H),
2.02 (s, 3H), 1.37 (s, 9H). 13C NMR: l 174.0, 154.6,
136.2, 129.3, 129.1, 128.1, 81.9, 50.8, 28.4, 20.1 4 R=
1
OCH2Ph, R%=CH3: H NMR (CDCl3): l 7.39–7.24 (m,
9. Merck silica gel 60 was used for all chromatographic
separations. The separation of compounds
3
was
5H), 5.14 (s, 2H), 3.17 (s, 3H), 1.42 (s, 9H). 13C NMR: l
156.8, 136.5, 128.8, 128.5, 128.3, 81.8, 68.2, 38.3, 28.6. 4
R=OCH2Ph, R%=CH2Ph: 1H NMR (CDCl3): l 7.57–
7.06 (m, 10H), 6.68–6.17 (m, 1H), 5.23 (s, 2H), 4.75 (s,
2H), 1.44 (s, 9H); 13C NMR: l 156.7, 136.9, 136.4, 129.2,
129.0, 128.6, 128.3, 128.2, 128.1, 82.0, 68.6, 54.0, 28.5. 4
R=OCH2Ph, R%=CH(CH3)COOEt: 1H NMR (CDCl3):
l 7.39–7.26 (m, 5H), 6.69–6.52 (m, 1H), 5.22 (pd, 1H),
5.10 (pd, 1H), 5.05–4.95, 4.85–4.73 (2m, 1H), 4.23–4.03
(m, 2H), 1.47 (d, J=7 Hz, 3H), 1.39, 1.35 (2s, 9H),
1.29–1.14 (m, 3H). 13C NMR: l 172.6, 156.4, 155.5,
136.1, 128.8, 128.5, 128.1, 81.6, 68.7, 61.8, 28.4, 14.5. For
the other compounds, see Ref. 12.
achieved by using a column chromatography (¥=3 cm)
and a mixture EtOAc/hexane as eluant. As an indication:
Rf (methylphthalimide)=0.45 with hexane/EtOAc 4/1.
10. 1H and 13C NMR spectra of all new compounds: 3
R=Ph, R%=CH3: 1H NMR (CDCl3): l 7.32–7.10 (m,
5H), 3.06 (s, 3H), 1.36 and 1.25 (2s, 18H); 13C NMR: l
172.7, 149.9, 134.8, 130.7, 128.2, 126.8, 84.6, 35.5, 28.1. 3
1
R=Ph, R%=CH2Ph: H NMR (CDCl3): l 7.57–7.22 (m,
10H), 4.89 (s, 2H), 1.43 and 1.29 (2s, 18H); 13C NMR: l
172.8, 135.2, 135.1, 131.1, 130.7, 128.8, 128.6, 128.3,
128.2, 84.7, 52.6, 28.2. 3 R=CH3 R%=CH3: 1H NMR
(CDCl3): l 3.06 (s, 3H), 1.93 (s, 3H), 1.50 (s, 18H); 13C
NMR: l 172.4, 150.0, 84.9, 34.9, 28.3, 20.2. 3 R=CH3
R%=CH2Ph: 1H NMR (CDCl3): l 7.27–7.16 (m, 5H),
4.61 (s, 2H), 1.91 (s, 3H), 1.27 (s, 18H); 13C NMR: l
172.6, 150.0, 135.3, 130.7, 128.7, 128.2, 54.6, 51.4, 28.1,
11. Stafford, J. A.; Brackeen, M. F.; Karanewsky, D. S.;
Valvano, N. L. Tetrahedron Lett. 1993, 34, 7873–7876.
12. (a) Maeorg, U.; Pehk, T.; Ragnarsson, U. Acta Chem.
Scand. 1999, 53 (12), 1127–1133; (b) Maeorg, U.; Grehn,
L.; Ragnarsson, U. Angew. Chem., Int. Ed. Engl. 1996, 35
(22), 2626–2627; (c) Seung-Hoi, K.; Rieke, R. D. J. Org.
Chem. 2000, 65, 2322–2330.
1
20.5. 3 R=OCH2Ph, R%=CH3: H NMR (CDCl3): l 13C
NMR: l 155.3, 150.2, 136.4, 128.8, 128.6, 128.3, 84.1,
68.4 and 68.1, 37.4 and 36.7, 28.2. 3 R=OCH2Ph, R%=
CH2Ph: 1H NMR (CDCl3): l 7.45–7.24 (m, 10H), 5.20 (s,