1,4-additions to gamma-aminoalkyl-substituted alpha-methylene gamma-butyrolactones: Synthesis of highly functionalized amino acid derivatives

[GRAPHICS] Addition of C and O-nucleophiles to alpha-amino acid derived alpha-methylen e gamma-butyrolactones led to the corresponding Michael adducts, Addition o f cuprates or cyanide, respectively, could be achieved with excellent selec tivities. Addition of malonate anion or methanolate could be performed with good yields, but with rather poor selectivities. Hydrogenation led to meth yl-substituted lactones, and ozonolysis yielded the corresponding alpha,bet a-dicarbonyis. The configuration of the products could be established by X ray crystallographic analyses and NOE experiments.