Synthesis, complete 1 H and 13 C NMR assignment and crystal structure of novel epoxide derivatives of cytochalasin B

Five novel epoxide derivatives of cytochalasin B were synthesized. Reaction of cytochalasin B with t ‐BHP and BuLi led to selective epoxidation of the C‐21/22 double bond to give a single monoepoxide, while reaction with m ‐CPBA yielded two diepoxides. Reaction of the monoepoxide with m ‐CPBA yielded two triepoxides. The relative configurations of the epoxides were elucidated by analogy with the natural product by means of spectroscopic methods; full assignment of NMR signals was achieved, and the absolute configuration was confirmed by X‐ray crystallography. Copyright © 2008 John Wiley & Sons, Ltd.