Dihalomethylation of N-protected phenylalanine esters
Dihalomethylation of several N-protected amino acid esters gave N-protected α-aminoalkyl-α′-dihalomethylketones, which are useful intermediates for the synthesis of erythro β-amino-α-hydroxycarboxylic acids, in good yield. The dihalomethylketones were successfully converted to N-protected α-aminoalkyl-α′-halomethylketones by selective catalytic hydrogenation.
Practical synthesis of α-aminoalkyl-α′-chloromethylketone derivatives. Part 2: Chloromethylation of N-imine-protected amino acid esters
Chloromethylation of N-imine-protected amino acid esters followed by acid hydrolysis gave α-aminoalkyl-α′-chloromethylketone as a HCl salt form in good yield without racemization. The amino group was conveniently protected with carbamate protecting reagents to give various useful intermediates for the protease inhibitors.