Enabling Modular Click Chemistry Library through Sequential Ligations of Carboxylic Acids and Amines.

High-throughput synthesis and screening of chemical libraries play pivotal roles in drug discovery. Click chemistry has emerged as a powerful strategy for constructing highly modular chemical libraries. However, the development of new click reactions and unlocking new click able building blocks remain exceedingly challenging. Here in , we describe a double-click strategy that enables the sequential ligation of widely available carboxylic acids and amines with fluorosulfuryl isocyanate (FSO 2 NCO) via a modular amidation/SuFEx process. This method provides facile access to chemical libraries of N-fluorosulfonyl amides (RCONHSO 2 F) and N-acylsulfamides (RCONHSO 2 NR ´ R ´´ ) in near-quantitative yields under simple and practical conditions. The robustness and efficiency of this double click strategy is showcased by the facile construction of chemical libraries in 96-well microtiter plates from a large number of carboxylic acids and amines. Preliminary biological activity screening reveals that some compound s  exhibit high antimicrobial activities against Gram-positive bacterium  S. aureus and drug-resistant MRSA (MIC up to 6.25·μg mL-1). These results provide compelling evidence for the potential application of modular click chemistry library as an enabling technology in high-throughput medicinal chemistry.