Highly Z-Selective Synthesis of Disubstituted α,β-Unsaturated Cyanides and Amides Using 10-P-5 Wittig Type Reagents

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 α,β-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 α,β-unsaturated amides with high Z-selectivity for both aromatic and aliphatic aldehydes (Z:E=99:1 to >99:<1).