A practical and azide-free synthetic approach to oseltamivir from diethyl D-tartrate.

A short and practical synthesis of oseltamivir was accomplished in 11 steps from inexpensive and abundant diethyl D-tartrate starting material. This azide-free route featured an asymmetric aza-Henry reaction and a domino nitro-Michael/Horner-Wadsworth-Emmons (HWE) reaction as the key steps to construct the relevant cyclohexene ring of the product, which provided an economical and practical alternative for the synthesis of oseltamivir.