5574
T. Takeda et al. / Tetrahedron Letters 44 (2003) 5571–5574
Scheme 2. Plausible pathway for the formation of pyrrolidines by titanocene(II)-promoted intramolecular reaction of N-[3,3-
bis(phenylthio)propyl]anilides.
from the Ministry of Education, Culture, Sports, Sci-
ence and Technology, Japan. This work was carried out
under the 21st Century COE program of ‘‘Future
Nano-materials’’ in Tokyo University of Agriculture &
Technology.
2000, 56, 763; (g) Takeda, T.; Takagi, Y.; Saeki, N.;
Fujiwara, T. Tetrahedron Lett. 2000, 41, 8377; (h) Rahim,
M. A.; Sasaki, H.; Saito, J.; Fujiwara, T.; Takeda, T.
Chem. Commun. 2001, 625.
8. Compound 4c: 1H NMR (500 MHz, CDCl3) l 0.90 (d,
J=6.7 Hz, 6H), 1.68–1.76 (m, 1H), 1.95 (dd, J=7.0, 7.0
Hz, 2H), 3.09 (s, 3H), 6.01 (t, J=7.0 Hz, 1H), 6.65–6.76
(m, 3H), 7.16–7.36 (m, 7H). When the allylic proton at
1.95 ppm was irradiated, NOE was observed on the
signal of the proton at the ortho-position of the aniline
moiety near 6.70 ppm.
References
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