One-pot conversion of β-aminocrotononitrile to secondary enaminonitriles including chiral ones — Application to synthesis

Abstract

A highly efficient one-pot conversion of β-aminocrotononitrile to secondary enaminonitriles including chiral ones is described. In contrast to β-aminocrotononitrile, some of these N-substituted β-enaminonitriles on reacting with acid chlorides show a unique preference for C-terminal selection allowing preparation of pyrazoles without separation of regioisomers. In addition, use of secondary enaminonitriles also provided access to pyrazoles that are not obtainable with primary enaminonitriles owing to an exclusive preference for N-terminal selection.Key words: β-aminocrotononitrile, N-substituted enaminonitriles, regioselective, pyrazoles.