Synthesis of m-DAP Lipid II (1b)a
aReagents and conditions: (a) i. Grubbs 2nd Gen. catalyst, DCM, 12h, reflux (50%); ii. H2/Pd, MeOH, 1 h, RT (90%); (b) i. NH2-D-Ala-D-Ala-OMe, EDC, HOBt, DIEA, DCM, 2h, RT; ii. 4M HCl in dioxane, 15 min., RT; iii. Boc-L-Ala-γ-D-Glu(OH)-OMe, EDC, HOBt, DIEA, DCM, 2h, RT; iv. 4M HCl in dioxane, 15 min., RT (54%); (c) i. 3, DMTNMM, DIEPA, MeOH, RT, 2h; ii. NaOH, H2O, dioxane, 45 min., RT (48%); (d) UDP-GlcNAc, MurG, buffer, 1h, RT.