Ph<sub>3</sub>As-Catalyzed Wittig-Type Olefination of Aldehydes with Diazoacetate in the Presence of Na<sub>2</sub>S<sub>2</sub>O<sub>4</sub>

In the presence of sodium hydrosulfite and a catalytic amount of AsPh<sub>3</sub> and Fe(TCP)Cl, aldehydes react with ethyl diazoacetate to give the corresponding α,β-unsaturated esters in high yields with excellent stereoselectivities (<i>E</i>/<i>Z</i> > 50/1).