“…1a-d Several recent reviews have been published covering pharmaceutically active compounds, 2 spiro-derivatives, 3a-b marine alkaloids, 4 iminosugar di-and oligosaccharides, 5a-b and alkaloid lipids. 6 Advances in synthetic methods include catalytic asymmetric aza Diels-Alder reactions, 7 benzotriazole mediated syntheses, 8 asymmetric synthesis, 9a-b and cyclization of allylsilyl-substituted N-acyliminium and iminium ions. 10 A special case of the preparation of n-membered non-aromatic azacycles is a ring expansion of (n-1) cyclic precursors fused to aziridine ring.…”