1,4-Additions to γ-Aminoalkyl-Substituted α-Methylene γ-Butyrolactones: Synthesis of Highly Functionalized Amino Acid Derivatives

Addition of C - and O -nucleophiles to α-amino acid derived α-methylene γ-butyrolactones led to the corresponding Michael adducts. Addition of cuprates or cyanide, respectively, could be achieved with excellent selectivities. Addition of malonate anion or methanolate could be performed with good yields, but with rather poor selectivities. Hydrogenation led to methyl-substituted lactones, and ozonolysis yielded the corresponding α,β-dicarbonyls. The configuration of the products could be established by X-ray crystallographic analyses and NOE experiments.