Reagents and conditions: (a) dl-proline (10 mol %), NCS, CH2CI2, 0 °C; (b) NaBH4, MeOH; 86%; (c) Tf2O, lutidine, DCM, −78 °C; (d) BnNHCH2CH2OH, DCM, −78 °C → rt; 78%; (e) KOfBu, CH3CN, −20 °C; 54%; (f) H2, Pd/C, MeOH; (g) R-Br, K2CO3, CH3CN, rt; (h) DIPEA, acid chloride, DMF, rt, 1 h; (i) Pd2(dba)3, XANTPHOS, Cs2CO3, aryl bromide, 1,4-dioxane, 100 °C, 18 h; (j) aryl isocyanate, THF, rt, 1 h; (k) DIPEA, sulfonyl chloride, DMF, 40 °C, 1 h