A STUDY OF THE REACTIVITY OF (METHYL 2-ACETAMIDOACRYLATE)-TRICARBONYLIRON(0) LEADING TO A NOVEL SYNTHESIS OF BETA,BETA,BETA-TRIALKYL ALPHA-AMINO-ACIDS

(Methyl 2-acetamidoacrylate)tricarbonyliron(0) (3) reacts with 2 equiv alents of methyllithium to give methyl N-acetylalaninate (4) and 2-ace tamido-4-oxopentanoate (5) when the reaction is quenched with trifluor oacetic acid. Production of methyl N-acetylalaninate is dependent only on the presence of trifluoroacetic acid, and the ratio of 4 to 5 gene rated in these reactions is related to the quantity of trifluoroacetic acid used to quench them. Addition of two equivalents of methyllithiu m followed by tertiary haloalkanes gives protected beta,beta,beta-tria lkyl alpha-amino acids which may be hydrolysed to give tert-leucine (1 3) and the new alpha-amino acids 2-amino-3,3-dimethylpentanoic acid (1 4) and 2-amino-3,3-dimethylhexanoic acid (15).