The first convergent Clo+ Clo route for vitamin A has been developed. The double elimination reaction of p-alkoxy or &halo sulfones proceeds with excellent stereocontrol to afford the all-trans and 13-cis isomers of W95% purity. The double elimination reaction of P- alkoxy sulfones is initiated by deprotonation of an allylic hydrogen in 9, while the reaction of &halo sulfones proceeds through the Michael addition of potassium methoxide. ...