A Chemistry for Incorporation of Selenium into DNA‐Encoded Libraries

Conventional direct C−H selenylation suffers from simple selenation with limited atom economy and complicated reaction system. In this work, we designed benzoselenazolone as a novel bifunctional selenide reagent for both off‐ and on‐DNA C−H selenylation under rhodium(III) catalysis. We show that using benzoselenazolone allowed production of a series of selenylation products containing an adjacent aminoacyl group in a fast and efficient way, with high atom economy. The synthetic application of this method was demonstrated by taking advantage of the amide functionality as a nucleophile, directing group, and amide coupling partner. This work shows great potential in facilitating rapid construction of selenium‐containing DNA‐encoded chemical libraries (SeDELs), and lays the foundation for the development of selenium‐containing drugs. Benzoselenazole is introduced as a bifunctional selenide reagent for both off‐ and on‐DNA C−H selenylation under rhodium(III) catalysis. The reaction shows great potential in facilitating rapid construction of selenium‐containing DNA‐encoded chemical libraries (SeDELs), and lays the foundation for the development of selenium‐containing drugs.