Abstract: Mycalamide B, a potent antitumour agent, was synthesised from cheap, readily available starting materials: ethyl lactate, ethyl isobutyrate, 4-chlorobutanal, and 4- chlorobutanoyl chloride. The trioxabicyclo [4.4. 0] decane ring system was created by reaction of a methoxymethyl ether with a silyloxyoxirane induced by phosphorus pentoxide.
