a(i) MgCl2, Me2NEt, CH2Cl2, RT; (ii) SeO2, dioxane, 100 °C; (iii) 0.5 mol. equiv. ethylenediamine, MeOH, RT; (iv) NaBH4, (v) Zn(OTf)2, 1:1 MeCN:H2O, RT – diastereomers of Zn•4 separated by RP-HPLC; (vi) excess DTPA, pH 5.0; (vii) glyoxylic acid, NaBH3CN, NaHCO3, MeOH. bJED was prepared from the (R,R/S,S) diastereomer of 4; (S,S) 4 and JED are depicted here.