Marine alkaloids possessing a perhydropyrrolo[2,1j]quinoline or perhydropyrido[2,1-j]quinoline skeleton have gained significant interest from the synthetic chemistry community for more than two decades because of their synthetically intriguing tricyclic structures. This family of alkaloid natural products include cylindricines, fasicularin, and lepadiformines (Figure ). Cylindricines were isolated by Blackman and co-workers from the ascidian Clavelina cylindrica collected in Tasmania. The gross structure and relative configuration of cylindricines A (1) and B (2) were determined by single crystal X-ray crystallographic analysis. These compounds were shown to exist as an equilibrating mixture in solution, possibly via generation of the corresponding aziridinium ion. Cylindricines C-J (3-10) were structurally characterized mainly by NMR spectroscopic analysis in comparison with 1 and 2. However, the specific rotation values of 1-10 were not reported, and the absolute configuration was left unassigned. While the absolute configuration of 1-10 cannot be determined unequivocally without re-isolation of authentic material, it is quite likely to be the same as that of lepadiformine A (11), which was isolated by Biard et al. from the Tunisian tunicate Clavelina lepadiformis Müller as a cytotoxic constituent (IC50 16.8 µg/mL against KB cells). The absolute configuration of 11 has been established through enantioselective total syntheses by Kibayashi 6 and Weinreb. A number of asymmetric and racemic total syntheses of cylindricines, fasicularin, and lepadiformines have been described to date. 8 Nonetheless, the synthetic development and biological evaluation of a collection of marine tricyclic alkaloids are yet to be achieved. Moreover, the biological activity of cylindricines has not been described so far except that a mixture of 1 and 2 was found toxic in brine shrimp bioassay. Here we describe total syntheses of cylindricines A-H (1-8) and the proposed structures of cylindricines I and J (9 and 10) from a single common spirocyclic pyrrolidine derivative.