Phosphoranes (10-P-5) bearing cyanomethyl, acetamide, and N, N-dimethylacetamide groups were examined for Wittig type reactions. All three reacted to give the corresponding olefins. The reaction of the cyanomethyl reagent with aldehydes gave alpha,beta-unsaturated cyanides with high Z-selectivity in the case of aliphatic aldehydes (Z : E = 94 : 6 to 99 : 1). On the other hand, the reactions of the two amide reagents with aldehydes yielded alpha,beta-unsaturated amides with high Z-selectivity for both aromatic and aliphatic aldehydes (Z : E = 99 : I to >99 : <1).