Regioselective enzymatic undecylenoylation of 8-chloroadenosine and its analogs with biomass-based 2-methyltetrahydrofuran as solvent

► Use of MeTHF as a promising alternative to THF for enzymatic acylation. ► Much better enzyme performance in MeTHF than in other media. ► Excellent regioselectivities (94->99%) of the enzymatic approach for nucleosides acylation. ► Revealing nucleoside substrate recognition of Penicillium expansum lipase for the first time.