By use of new NMR techniques, in particular, long range J-resolved 2D NMR (LRJR), the structure of oxirapentyn, which is an antibiotic produced by Beauveria felina, has been established as shown in Fig. 8. LRJR has proved to be a very powerful method to analyzed ^<13>C-^1H long range couplings and will become one of the most important methods for structural elucidation of natural products.
