Total synthesis of MAG 4. Reagents and conditions: (a) Boc-Gly-OH, EDCI, HOBt, DIPEA (66%); (b) TFA, CH2Cl2 (98%); (c) see ref. ; (d) acrylic acid, 5% Grubbs' second-generation catalyst (92%); (e) H2, Pd/C, MeOH (97%); (f) 6, EDCI, HOBt, DIPEA (97%); (g) Fmoc-Gly-OH, (COCl)2, DMF; (h) piperidine, DMF (43%, over two steps); (i) 1.0 M LiOH H2O/THF, 0 °C (80%); (j) N-methoxycarbonylmaleimide, NaHCO3, THF/H2O (71%) and (k) HCl-saturated EtOAc (87%). Boc, t-butoxycarbonyl; CH2Cl2, dichloromethane; (COCl)2, oxalyl chloride; DIPEA, diisopropylethylamine; DMF, N,N-dimethylformamide; EDCI, N-ethyl-N′-(3-dimethyldiaminopropyl)-carbodiimide HCl; EtOAc, ethyl acetate; Fmoc, 9-fluorenylmethoxycarbonyl; HOBt, 1-hydroxybenzotriazole hydrate; MeOH, methanol; Pd/C, palladium on carbon; TFA, trifluoroacetic acid; THF, tetrahydrofuran.