Amino esters, such as Tamiflu, are known to have antiviral activity. Using a [3+3] annulation, several different amino esters have been concisely synthesized. The annulation is achieved using a Horner-Wadsworth Emmons type reagent and an α,β-unsaturated aldehyde or ketone in the presence of  1,8-diazobicyclo[5.4.0]-undec-7-ene.