A wide variety of natural products have been isolated from Didemnum species of ascidians, and a survey of such compounds is presented. The didemnaketals are the only spiroacetal containing natural products to be elaborated by this genus, with didemnaketal A showing the greatest activity against HIV-1 protease. General synthetic approaches to the spiroacetal moiety are discussed, and then applied in retrosynthetic analyses of the spiroacetal portion of didemnaketal A. Synthesis towards this spiroacetal portion is reported, with the products being characterised by detailed 2D NMR spectroscopy and other methods. The relative stereochemistry at C12, C14, C16, C18 and C20 in the natural product is established. Further extensions of the synthesis are discussed. Two models of the E,F bicyclic portion of the shellfish poison, pinnatoxin D, are synthesised, and characterised by detailed 2D NMR analysis. The relative stereochemistry at C27, C29 and C30 is established by this synthetic work, and is in agreement with that based only on NMR analyses. This work has been published. {Suthers, B.D., Jacobs, M.F., Kitching, W. Tetrahedron Letters 39, 2621-2624 (1998)}
| Identifer | oai:union.ndltd.org:ADTP/253699 |
| Creators | Suthers, Bill Derek |
| Source Sets | Australiasian Digital Theses Program |
| Detected Language | English |
Page generated in 0.0017 seconds