Microbial transformations have been employed as a means of preparing analogues of the diterpene aphidicolin. Microbial transformation products were initially identified by thin-layer chromatography of fermentation extracts and then were prepared by larger scale incubations. Each microbial metabolite was subjected to structure elucidation employing carbon-13 and proton NMR, high-resolution mass spectrometry, and infrared analysis. ...