1: Methyltriphenylphosphonium bromide With potassium tert-butylate in tetrahydrofuran T=0 - 20°C; 1.08333 h; 2: (S)-tert-butyl 2-((tert- butoxycarbonyl)amino)-5-oxopentanoate in tetrahydrofuran T=0 - 20°C;