Abstract N-carbomethoxy-5-ethyl, 1, 2-dihydropyridine (1) may be prepared by the bromination of N-carbomethoxy-3-ethyl-1, 2, 5, 6-tetrahydropyridine (10), and subsequent double dehydrobromination with EtAlCl 2/HMPA; this diene undergoes Diels-Alder reaction with dimethyl methylenemalonate (2) to give the isoquinuclidine (3), an intermediate in our planned approach to catharanthine.
[Keyser, Jean-Luc De; Cock, Christian J. C. De; Poupaert, Jacques H.; Dumont, Pierre Journal of Organic Chemistry, 1988 , vol. 53, # 20 p. 4859 - 4862]