1. (a) Toye, J.; Ghosez, L. J. Am. Chem. Soc. 1975, 97, 2276–2277. (b) De Kimpe, N.; Verhé, R.; De Buyck, L.; Chys, J.; Schamp, N. Org. Prep. Proced. Int. 1978, 10, 149–156. (c) Ahbrecht, H.; Pfaff, K. Synthesis 1978, 897–898. (d) De Kimpe, N.; Verhé, R.; De Buyck, L.; Chys, J.; Schamp, N. Bull. Soc. Chim. Belg. 1979, 88, 59–65. (e) De Kimpe, N.; Verhé, R.; De Buyck, L.; Schamp, N. Synthesis 1979, 741–743. (f) Lesur, B.; Toye, J.; Chantrenne, M.; Ghosez, L. Tetrahedron Lett. 1979, 28, 2835–2838. (g) De Lombaert, S.; Lesur, B.; Ghosez, L. Tetrahedron Lett. 1982, 28, 4251–4254. (h) Costisella, B.; Gross, H. Tetrahedron 1982, 38, 139–145. (i) Takahashi, K.; Shibasaki, K.; Ogura, K.; Iida, H. J. Org. Chem. 1983, 48, 3566–3569. (j) De Kimpe, N.; Verhé, R.; De Buyck, L.; Schamp, N. Chem. Ber. 1983, 116, 3846–3857. (k) Ahlbrecht, H.; Ibe, M. Synthesis 1985, 421–423. (l) Fang, J.-M.; Chang, H.-T. J. Chem. Soc., Perkin Trans. 1 1988, 1945–1948. (m) Fang, J.-M.; Chang, H.-T, Lin, C.-C. J. Chem. Soc., Chem. Commun. 1988, 1385–1386. (n) Fang, J.-M.; Yang, C.-C.; Wang, Y.-W. J. Org. Chem. 1989, 54, 477–481. (o) Fang, J.-M.; Yang, C.-C.; Wang, Y.-W. J. Org. Chem. 1989, 54, 481–484. (p) Fang, J.-M.; Chen, C.-C. J. Chem. Soc., Chem. Commun. 1990, 3365–3367. (q) Schwarz, J. B.; Devine, P. N.; Meyer, A. I. Tetrahedron 1997, 53, 8795–8806.
2. (a) De Kimpe, N.; Verhé, R.; De Buyck, L.; Chys, J.; Schamp, N. J. Org. Chem. 1978, 43, 2670–2672. (b) De Kimpe, N.; Verhé, R.; De Buyck, L.; Schamp, N. Org. Prep. Proced. Int. 1982, 14, 213–215.
3. (a) Adam, W.; Lucchi, O. D.; Quart, H.; Recktenwald, R.; Yang, F. Angew. Chem., Int. Ed. Engl. 1979, 18, 788–789. (b) Ito, Y.; Matsuura, T.; Kondo, H. J. Am. Chem. Soc. 1979, 101, 7105–7107. (c) Ito, Y.; Yokoya, H.; Kyono, K.; Yamamura, S.; Yamada, Y.; Matsuura, T. J. Chem. Soc., Chem. Commun. 1980, 898–890. (d) Breslin, D. T.; Fox, M. A. J. Am. Chem. Soc. 1993, 115, 11716–11721. (e) Jaroszewski, J. W.; Ettlinger, M. G. J. Org. Chem. 1988, 53, 4635–4637.
4. (a) Seo, Y.; Mun, K. R.; Kim, K. Synthesis 1991, 951–953. (b) Seo, Y.; Mun, K. R.; Lee, Y. Y.; Kim, K. J. Korean Chem. Soc. 1992, 36, 453–459.
5. Typical procedure: To a solution of 4a (386 mg, 1.36 mmol) in toluene (10 mL) was added Et2AlCN (8.24 mmol, 1 M solution/toluene, 8.24 mL) under a nitrogen atmosphere. The mixture was heated for 9 h at reflux, followed by addition of water (1 mL) to the cooled reaction mixture. The white solids formed were filtered and washed with CH2Cl2 (50 mL×3). The filtrate was dried over MgSO4. Evaporation of the solvent, followed by chromatography (silica gel, 70–230 mesh, 2×20 cm) of the residue with benzene gave 3-methyl-2-phenylamino-2-butenenitrile 3a (96 mg, 41%): mp 61–63°C (n-hexane); 1H NMR (CDCl3, 300 MHz) δ 1.86 (s, 3H, Me), 2.12 (s, 3H, Me), 4.87 (s, br, 1H, NH), 6.66 (d, 2H, J=8.4 Hz, ArH), 6.84 (t, 1H, J=8.0 Hz, ArH), 7.23 (t, 2H, J=8.4 Hz, ArH); 13C NMR (CDCl3, 75 MHz) δ 19.22, 22.03, 108.76, 114.23, 116.43, 119.98, 129.36, 143.81, 150.02; IR (KBr) 3360, 2208 (CN), 1633 cm−1; MS (EI) m/z 172 (M+, 100), 157 (M+−Me, 89). Anal. calcd for C11H12N2: C, 76.71; H, 7.02; N, 16.27. Found: C, 76.65; H, 7.12; N, 16.23.