Asymmetric Syntheses via Heterocyclic Intermediates; XXVII1. Enantioselective Synthesis of [2-Methoxyethoxymethyl-Protected] (R)- Homoserine Methyl Esters and (R)-α-Methyl-homoserine Methyl Esters and of the Corresponding α-Amino-γ-lactones by the Bis-lactim Ether Method