In contrast to cyanomethylene triphenylphosphorane, the corresponding arsorane could react with a series of ketones giving the α,β-unsaturated nitrite in fair to good yields. The products and their yields are shown in Table 1. This result shows again that the arsonium glide is more reactive than the corresponding phosphonium glide. It is worthwhile to point out that this glide also could be obtained from the arsonium salt on treating with the weak base piperidine, and reacted with a-tetralone in situ under the mild conditions. The pure egocyclic olefinic product was obtained in 33% yield. When this glide reacted with 4-cholesten-3-one, the yield of the olefinio products was 87%.Their configurations were ascertained by ¹H NMR spectra. Therefore in the above two cases, this arsonium glide seems to be superior than Horner-Wittig reagent.