Tuning Glycosyl Donor Reactivity via Nitroarene Protecting Groups: A Semiarmed Strategy for Selective Glycosylation

Herein, a modular strategy for tuning the reactivity of glycosyl donors using nitroarene (NA) protecting groups such as 4‐nitrobenzyl, 4‐nitrobenzoyl, and 4‐nitrophenyl. The electron‐withdrawing nature of the nitro group markedly reduces donor reactivity, enabling selective activation. Notably, these NA groups can be readily transform into electron‐donating pivaloylaminoarene (PA) and methoxycarbonylaminoarene (MCA) groups via nitro reduction followed by acylation or carbamation. This chemical conversion significantly enhances donor reactivity, offering a switchable reactivity platform. Relative reactivity values (RRVs), determined through competitive glycosylation, establish the reactivity trend: NA < arene < PA < MCA. Applying this strategy, an efficient synthesis of a series of disaccharides is achieved, demonstrating its utility in extending the conventional armed–disarmed approach in glycosylation chemistry.