Abstract
Use of a microwave-labile leaving group, 2,4-dinitrophenyl (2,4-DNP), leads to O-glycosylation in 70-80% yields with high α-selectivity. The 2,4-DNP glycosyl donors, protected with electron-donating benzyl ethers, gave the best results under controlled microwave conditions, which were all conducted in polar aprotic solvents, such as DMF, and were all conducted in the absence of any reagent-activating additives such as a Lewis acid/base or Brønsted-Lowry acid/base. This method represents concerted efforts towards reagent-free neutral glycosylation.