Concise, Stereoselective Syntheses of (+)- and (-)-Crispine A
Alkaloid, (+)-Crispine A (1) was isolated from Carduus crispus in 2002; it is known to possess significant cytotoxic activity especially against SKOV3, KB and Hela human cancer cell lines1. For the first time, concise, linear and protecting group-free stereoselective syntheses of both antipodes of Crispine A have been achieved in 6 steps starting from commercially available Veratraldehyde. The full synthetic sequence involving asymmetric Keck allylation and Pummerer rearrangement as crucial transformations will be presented.
Acknowledgements: This study was supported in part by United States Department of Agriculture, Agricultural Research Service, Specific Cooperative Agreement No. 58 – 6408 – 02 – 1-612. References:  Zhang Q, Tu G, et al. (2002) Tetrahedron, 58: 6795 – 6798.