1: 99 percent / 1,5-diazabicyclo<5.4.0>undec-5-ene (DBU) / tetrahydrofuran / 0.5 h / 0 °C 2: 1.) N-hydroxysuccinimide, N,N-dicyclohexylcarbodiimide (DCC) / 1.) THF, 2.) RT 3: 57 percent / thiophenol, Zn-Cu complex / dimethylformamide / 1 h / 65 °C 4: 86 percent / 1N NaOH / H2O / 0.67 h / Heating 5: 43 percent / anhyd liquid ammonia, Li / Heating View Scheme

With  1,5-diazabicyclo[5.4.0]undeca-5-ene in  tetrahydrofuran T=0°C; 0.5 h;   

Multi-step reaction with 3 steps 1: DBU / tetrahydrofuran / 0 °C2: 60 percent3: 45 percent / Zn(Cu), benzenethiol / dimethylformamide