To a vial containing N-(3-(3,6-dibromo-9H-carbazol-9-yl)-2-fluoropropyl)-N-(3-methoxyphenyl)-4-nitrobenzenesulfonamide (21.0 mg, 0.030 mmol; see representative procedure 4) was added lithium hydroxide (3.2 mg, 0.134 mmol), dimethylformamide (0.5 ml, 0.06 M) and mercaptoacetic acid (4.2 ul 0.060 mmol). After stirring at rt for 1 h the reaction mixture was diluted with EtOAc and washed sequentially with water, saturated sodium bicarbonate solution, water (3×) and brine. The organic layer was dried over Na2SO4, filtered and condensed. The crude reaction mixture was purified in 30% EtOAc/hexanes (+0.2% TEA), with 13.6 mg isolated. Yield=88%
