Efficient Access to Oseltamivir Phosphate (Tamiflu) via the <i>O‐</i>Trimesylate of Shikimic Acid Ethyl Ester

Abstract

The same azide intermediate as that used in the current technical synthesis of Tamiflu can be prepared in only eight steps and with only three workups; protecting group manipulations and chromatographic purification are not required. This approach includes a new protocol for aziridine formation to avoid competitive aromatization.