Scheme 2. Synthesis of the 4,5-Dihydrobenzodiazepinone-Based Compounds 2, 3, and 25–27: (A) Synthesis of the 4,5-Dihydrobenzodiazepinone Headgroup; Reagents and Conditions: (a) 12/13, DIPEA, DMF, 85 °C, 14 h, 82–99%; (b) TFA, CH₂Cl₂, rt, 2 h, then Fe, AcOH, 100 °C, 4 h, 75–83% over Two Steps; (B) Synthesis of 4,5-Dihydrobenzodiazepinone-Based Compounds 2, 3, and 25–27; (c) Pent-4-yn-1-yl Methanesulfonate, KI, DIPEA, DMF, μλ, 100 °C, 1 h, 62%; (d) HBPin, Cp₂ZrClH, DCE, 60 °C, 20 h, 72%; (e) 31/32, Pd(PPh₃)₂Cl₂, K₂CO₃, 1,4-Dioxane, H₂O, 100 °C, 89–99%; (f) Grubbs I Catalyst, HSiEt₃, Tol, 40 °C, 2 h, 69%; (g) Vinylsilane, 1 M BCl₃ in Heptane, CH₂Cl₂, 0 °C, 16 h, then 31, Pd(Amphos)₂Cl₂, K₂CO₃, Toluene, THF, EtOH, H₂O, 100 °C, 80% over Two Steps; (h) 29, Pd(OAc)₂, Cu(I)I, PPh₃, NEt₃, 100 °C, 44%; (i) 12, DIPEA, DMF, 85 °C, 14 h, 66%; (j) TFA, CH₂Cl₂, rt, 2 h, then Fe, AcOH, 100 °C, 30 min, 44%; (k) H₂, 10% Pd/C, EtOH, rt, 3 h, 78%.