With abundant quantities of 6 and 7 in hand, their halogenating potential was explored on the antifungal agent voriconazole (3), a substrate identified as being particularly difficult to halogenate under a variety of conditions (Table ). Indeed, 23 different chlorinating and brominating reagents/conditions were explored. A small selection of the most potent of these combinations are depicted with the highest yields ranging from 27-36%. In these optimal known conditions, the yields were determined by NMR; many of these reactions produced a number of other impurities aside from recovered starting material. In contrast, reagents 6 and 7 cleanly provided the desired chlorinated (3-Cl, 52% isolated) and brominated (3-Br, 79% isolated) products respectively, along with re-covered starting material without the use of exotic solvents or acidic additives. The optimal conditions (generally 0.1 to 0.15M in MeCN at room temperature-60°C, 1-40 h) were arrived upon after extensive screening (see SI for solvent effect). Notably, unlike many other halogenating agents and conditions, the reaction workup is extremely simple involving only solvent removal followed by purification with no aqueous wash needed. A number of other anomeric amide derivatives were also explored (Table ) by varying the N-and O-substituents however no improvement was observed. Increasing the steric hindrance around either atom substantially decreased reactivity. Finally, considering that the starting material (4-nitrobenzoyl chloride) for preparing 6 is less expensive than 4-cyanobenzoly chloride for making was chosen as the optimal chlorinating reagent.