Tris(2-methoxymethoxyphenyl)phosphine was readily quaternized when treated with Me bromoacetate. The resulting phosphornium salt was deprotonated to give the corresponding ylide (2-MeOCH2OC6H4)3P+CH-CO2Me (I). I reacted with satd., unsatd., or a-alkoxy substituted aliph. aldehydes to produce a,b-unsatd. esters with moderate to excellent cis-selectivity when methanol was used as the solvent. Thus, I reacted with isobutyraldehyde in MeOH to give a 91:9 mixt. of cis- and trans-Me2CHCH:CHCO2Me. Similarly, aldehyde II gave a 95:5 mixt. of cis- and trans-ester III. [on SciFinder (R)]