Scheme 2.

Synthesis of compound 1 analogs to explore the LHS phenylpiperazine moiety.^a

^a Reagents and Conditions: (a) NaI/K₂CO₃, CH₃CN, reflux, 6 h, 50–70% yield; (b) Pd₂(dba)₃, BINAP, t-BuONa, toluene, sealed tube, 100 °C, overnight, 52–89% yield; (c) TFA, CH₂Cl₂, r.t., 1 h, 92–96% yield; (d) Pd₂(dba)₃, BINAP, t-BuONa, toluene, sealed tube, 100 °C, 4h, 56–67% yield; (e) Pd(PPh₃)₄, K₂CO₃, dioxane, H₂O, microwave, 93% yield.