A new and convenient method for the synthesis of dehydroamino acids starting from ethyl N-Boc- and N-Z-α-tosylglycinates and various nitro compounds

Ethyl N-Boc- and N-Z-alpha-tosylglycinates, which were readily available from t-butyl or benzyl carbamate, ethyl glyoxylate, and sodium p-toluenesulfinate in formic acid, were reacted with a variety of nitro compounds in the presence of a base to afford the corresponding alpha,beta-didehydroamino acid derivatives in good yields. Eventually, it was found that the (Z)-isomer was predominantly formed in the present method.