Modular Chemoenzymatic Synthesis of Terpenes and their Analogues.

Non-natural terpenoids offer potential as pharmaceuticals and agrochemicals. However, their chemical syntheses are often long, complex, and not easily amenable to large-scale production. Herein, we report a modular chemoenzymatic approach to synthesize terpene analogues from diphosphorylated precursors produced in quantitative yields. Through the addition of prenyl transferases, farnesyl diphosphates, (2E,6E)-FDP and (2Z,6Z)-FDP, were isolated in greater than 80 % yields. The synthesis of 14,15-dimethyl-FDP, 12-methyl-FDP, 12-hydroxy-FDP, homo-FDP, and 15-methyl-FDP was also achieved. These modified diphosphates were used with terpene synthases to produce the unnatural sesquiterpenoid semiochemicals (S)-14,15-dimethylgermacrene D and (S)-12-methylgermacrene D as well as dihydroartemisinic aldehyde. This approach is applicable to the synthesis of many non-natural terpenoids, offering a scalable route free from repeated chain extensions and capricious chemical phosphorylation reactions.