(a) HCl, MeOH. (b) BH3-Me2S, Anhydrous THF, 0
°C. (c) EDCI, DMAP, NH3 in dioxane (0.5M), THF. (d) EDCI,
DMAP, (E)-4-methoxy-4-oxobut-2-enoic acid. (e) Anhydrous THF,
(E)-methyl 4-chloro-4-oxobut-2-enoate, 4Å molecular
sieves, 165 °C, µW. (f) methyl 4-oxobutanoate,
BH3-Me2S, THF. (g) EDCI, DMAP, 4-fluorobutanoic acid,
DCM (h) NaOH, EtOH:H2O.