New structures are being determined all the time. A recent issue of one important journal
(Tetrahedron Letters No. 14 of 1996) has a paper on Taxol but also reports the discovery and struck ture determination of the two new natural products in the margin. Both compounds were discovered in ocean sponges, one from Indonesia and one from a Fungus living in a sponge common in the Pacific and Indian oceans. Both structures were determined largely by NMR and in neither case was an X-ray structure necessary. You should feel a bit more in tune with the chemists who deduced these structures as they look much simpler than Taxol or even than penicillin. We hope you will feel by the end of this chapter that you can tackle structural problems of this order of complexity with some confidence. You will need practice, and in this area above all it is vital that you try plenty of problems. Use the examples in the text as worked problems: try to solve as much as you can before reading the answer-you can do this only the first time you read because next time you will have your memory as a prompt.